Three-dimensional data encoding method, three-dimensional data decoding method, and program

Abstract

To provide a three-dimensional data encoding method or the like capable of improving encoding efficiency.SOLUTION: Provided is a three-dimensional encoding method for encoding point cloud data indicating a plurality of three-dimensional positions in a three-dimensional space, including: moving the point cloud data by a common movement amount (S6871); dividing the point cloud data into a plurality of sub point cloud datasets by dividing the three-dimensional space into a plurality of subspaces (S6872); moving each sub point cloud dataset by an individual movement amount based on a position of a subspace that includes the sub point cloud data for each of the plurality of sub point cloud data included in the point cloud data after being moved by the common movement amount (S6873); and generating a bit stream by encoding the plurality of sub point cloud datasets after the movement (S6874), wherein the bit stream includes common movement information for calculating a common movement amount and a plurality of pieces of individual movement information for respectively calculating a plurality of individual movement amounts by which the plurality of sub point cloud datasets are moved.SELECTED DRAWING: Figure 120

Description

[Technical field]

[0001] The present disclosure relates to a three-dimensional data encoding method, a three-dimensional data decoding method, and a program. [Background technology]

[0002] In the future, devices and services that utilize 3D data are expected to become widespread in a wide range of fields, such as computer vision for autonomous operation of automobiles or robots, map information, monitoring, infrastructure inspection, video distribution, etc. 3D data is acquired in various ways, such as distance sensors such as range finders, stereo cameras, or a combination of multiple monocular cameras.

[0003] One method of expressing three-dimensional data is a method called a point cloud, which represents the shape of a three-dimensional structure using a group of points in a three-dimensional space. In a point cloud, the positions and colors of the points are stored. Point clouds are expected to become the mainstream method of expressing three-dimensional data, but point clouds have a very large amount of data. Therefore, when storing or transmitting three-dimensional data, it is essential to compress the amount of data by encoding, just like two-dimensional video images (examples include MPEG-4 AVC or HEVC standardized by MPEG).

[0004] In addition, compression of point clouds is partially supported by public libraries (Point Cloud Library) that perform point cloud-related processing.

[0005] Furthermore, a technique is known that uses three-dimensional map data to search for and display facilities located around a vehicle (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2014 / 020663 Summary of the Invention [Problem to be solved by the invention]

[0007] In the encoding and decoding of three-dimensional data, it is desirable to be able to improve the encoding efficiency.

[0008] An object of the present disclosure is to provide a three-dimensional data encoding method, a three-dimensional data decoding method, a three-dimensional data encoding device, or a three-dimensional data decoding device that can improve encoding efficiency. [Means for solving the problem]

[0009] A three-dimensional data encoding method according to one aspect of the present disclosure is a three-dimensional data encoding method for encoding point cloud data indicating a plurality of three-dimensional positions in a three-dimensional space, the method comprising: dividing the three-dimensional space into a plurality of sub-spaces to divide the point cloud data into a plurality of sub-point cloud data; calculating a common movement amount for the plurality of sub-point cloud data, the common movement amount being a movement of the same distance between the plurality of sub-point cloud data and indicating a movement in a direction toward a predetermined point in the three-dimensional space; moving the plurality of sub-point cloud data by the common movement amount; calculating a plurality of individual movement amounts corresponding to the plurality of sub-point cloud data moved by the common movement amount, the plurality of individual movement amounts being movements of different distances between the plurality of sub-point cloud data moved by the common movement amount and indicating a movement in a direction toward the predetermined point; for each of the plurality of sub-point cloud data moved by the common movement amount, moving the sub-point cloud data by an individual movement amount corresponding to the sub-point cloud data; and encoding the plurality of sub-point cloud data each moved by the corresponding individual movement amount.

[0010] A three-dimensional data decoding method according to one aspect of the present disclosure includes: decoding, from a bit stream, a plurality of sub-point cloud data obtained by dividing point cloud data indicating a plurality of three-dimensional positions by dividing a three-dimensional space into a plurality of subspaces, each of the sub-point cloud data being moved by a common movement amount and a corresponding individual movement amount; common movement information for calculating the common movement amount; and a plurality of individual movement information for calculating each of the plurality of individual movement amounts by which the plurality of sub-point cloud data were moved; the common movement amount is a movement of the same distance between the plurality of sub-point cloud data and indicates a movement in a direction toward a specified point in the three-dimensional space; the plurality of individual movement amounts by which the plurality of sub-point cloud data are moved are movement of different distances between the plurality of sub-point cloud data moved by the common movement amount and indicate a movement in a direction toward the specified point; and restoring the point cloud data by moving each of the plurality of sub-point cloud data by an amount obtained by adding the common movement amount and the individual movement amount corresponding to the sub-point cloud data.

[0011] A three-dimensional data encoding method according to one embodiment of the present disclosure is a three-dimensional data encoding method for encoding point cloud data indicating a plurality of three-dimensional positions in a three-dimensional space, comprising the steps of: moving the point cloud data by a first movement amount; dividing the three-dimensional space into a plurality of sub-spaces, dividing the point cloud data into a plurality of sub-point cloud data; moving each of the plurality of sub-point cloud data included in the point cloud data after moving the first movement amount by a second movement amount based on the position of the sub-space in which the sub-point cloud data is included; and encoding the plurality of sub-point cloud data after movement to generate a bit stream, wherein the bit stream includes first movement information for calculating the first movement amount and a plurality of second movement information for calculating each of the plurality of second movement amounts by moving the plurality of sub-point cloud data.

[0012] A three-dimensional data decoding method according to one embodiment of the present disclosure decodes from a bit stream a plurality of sub-point cloud data obtained by dividing a three-dimensional space into a plurality of subspaces to divide point cloud data indicating a plurality of three-dimensional positions, each of the sub-point cloud data being moved by a first movement amount and a corresponding second movement amount, first movement information for calculating the first movement amount, and a plurality of second movement information for calculating each of the plurality of second movement amounts by which the plurality of sub-point cloud data have been moved, and restores the point cloud data by moving each of the plurality of sub-point cloud data by an amount obtained by adding up the first movement amount and the corresponding second movement amount. Effect of the Invention

[0013] The present disclosure can provide a three-dimensional data encoding method, a three-dimensional data decoding method, a three-dimensional data encoding device, or a three-dimensional data decoding device that can improve encoding efficiency. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a diagram showing a configuration of a three-dimensional data encoding / decoding system according to the first embodiment. [Diagram 2] FIG. 2 is a diagram illustrating an example of a configuration of point cloud data according to the first embodiment. [Diagram 3] FIG. 3 is a diagram showing an example of a configuration of a data file in which point cloud data information according to the first embodiment is described. [Figure 4] FIG. 4 is a diagram showing types of point cloud data according to the first embodiment. [Diagram 5] FIG. 5 is a diagram showing a configuration of a first encoding unit according to the first embodiment. [Figure 6] FIG. 6 is a block diagram of a first encoding unit according to the first embodiment. [Figure 7] FIG. 7 is a diagram showing a configuration of a first decoding unit according to the first embodiment. [Figure 8] FIG. 8 is a block diagram of a first decoding unit according to the first embodiment. [Figure 9]FIG. 9 is a diagram showing a configuration of a second encoding unit according to the first embodiment. [Figure 10] FIG. 10 is a block diagram of a second encoding unit according to the first embodiment. [Figure 11] FIG. 11 is a diagram illustrating a configuration of a second decoding unit according to the first embodiment. [Figure 12] FIG. 12 is a block diagram of a second decoding unit according to the first embodiment. [Figure 13] FIG. 13 is a diagram showing a protocol stack related to PCC encoded data according to the first embodiment. [Figure 14] FIG. 14 is a diagram showing a basic structure of the ISOBMFF according to the second embodiment. [Figure 15] FIG. 15 is a diagram illustrating a protocol stack according to the second embodiment. [Figure 16] FIG. 16 is a diagram showing an example in which the NAL unit according to the second embodiment is stored in a file for codec 1. In FIG. [Figure 17] FIG. 17 is a diagram showing an example in which the NAL unit according to the second embodiment is stored in a file for codec 2. In FIG. [Figure 18] FIG. 18 is a diagram illustrating a configuration of a first multiplexing unit according to the second embodiment. In FIG. [Figure 19] FIG. 19 is a diagram showing a configuration of a first demultiplexing unit according to the second embodiment. In FIG. [Figure 20] FIG. 20 is a diagram illustrating a configuration of a second multiplexing unit according to the second embodiment. In FIG. [Figure 21] FIG. 21 is a diagram showing a configuration of a second demultiplexing unit according to the second embodiment. In FIG. [Figure 22] FIG. 22 is a flowchart of a process performed by the first multiplexing unit according to the second embodiment. [Figure 23] FIG. 23 is a flowchart of a process by the second multiplexing unit according to the second embodiment. [Figure 24] FIG. 24 is a flowchart of processing by the first demultiplexing unit and the first decoding unit according to the second embodiment. [Diagram 25]FIG. 25 is a flowchart of processing by the second demultiplexing unit and the second decoding unit according to the second embodiment. [Figure 26] FIG. 26 is a diagram showing configurations of an encoding unit and a third multiplexing unit according to the third embodiment. In FIG. [Figure 27] FIG. 27 is a diagram showing configurations of a third demultiplexing unit and a decoding unit according to the third embodiment. In FIG. [Figure 28] FIG. 28 is a flowchart of a process by the third multiplexing unit according to the third embodiment. [Figure 29] FIG. 29 is a flowchart of a process performed by a third demultiplexing unit and a decoding unit according to the third embodiment. [Diagram 30] FIG. 30 is a flowchart of a process performed by the three-dimensional data storage device according to the third embodiment. [Diagram 31] FIG. 31 is a flowchart of a process performed by the three-dimensional data acquisition device according to the third embodiment. [Diagram 32] FIG. 32 is a diagram showing configurations of an encoding unit and a multiplexing unit according to the fourth embodiment. In FIG. [Diagram 33] FIG. 33 is a diagram showing an example of a structure of encoded data according to the fourth embodiment. In FIG. [Diagram 34] FIG. 34 is a diagram showing an example of the structure of coded data and an NAL unit according to the fourth embodiment. [Diagram 35] FIG. 35 is a diagram illustrating an example of the semantics of pcc_nal_unit_type according to the fourth embodiment. [Diagram 36] FIG. 36 is a diagram showing an example of a transmission order of NAL units according to the fourth embodiment. [Figure 37] FIG. 37 is a diagram showing an example of division into slices and tiles according to the fifth embodiment. [Figure 38] FIG. 38 is a diagram showing an example of a division pattern of slices and tiles according to the fifth embodiment. [Figure 39] FIG. 39 is a block diagram of a first encoding unit according to the sixth embodiment. [Diagram 40]FIG. 40 is a block diagram of a first decoding unit according to the sixth embodiment. [Diagram 41] FIG. 41 is a diagram showing examples of the shape of tiles according to the sixth embodiment. [Diagram 42] FIG. 42 is a diagram showing examples of tiles and slices according to the sixth embodiment. In FIG. [Diagram 43] FIG. 43 is a block diagram of a division unit according to the sixth embodiment. [Diagram 44] FIG. 44 is a diagram showing an example of a map in which the point cloud data according to the sixth embodiment is viewed from above. [Diagram 45] FIG. 45 is a diagram showing an example of tile division according to the sixth embodiment. [Figure 46] FIG. 46 is a diagram showing an example of tile division according to the sixth embodiment. [Figure 47] FIG. 47 is a diagram showing an example of tile division according to the sixth embodiment. [Figure 48] FIG. 48 is a diagram showing an example of tile data stored in the server according to the sixth embodiment. [Figure 49] FIG. 49 is a diagram showing a system relating to tile division according to the sixth embodiment. [Figure 50] FIG. 50 is a diagram showing an example of slice division according to the sixth embodiment. [Figure 51] FIG. 51 is a diagram showing an example of a dependency relationship according to the sixth embodiment. In FIG. [Figure 52] FIG. 52 is a diagram showing an example of a data decoding order according to the sixth embodiment. [Diagram 53] FIG. 53 is a diagram showing an example of coded data of a tile according to the sixth embodiment. In FIG. [Figure 54] FIG. 54 is a block diagram of a coupling unit according to the sixth embodiment. [Figure 55] FIG. 55 is a diagram showing an example of the structure of coded data and a NAL unit according to the sixth embodiment. [Figure 56] FIG. 56 is a flowchart of the encoding process according to the sixth embodiment. [Figure 57]FIG. 57 is a flowchart of the decoding process according to the sixth embodiment. [Figure 58] FIG. 58 is a diagram illustrating an example of the syntax of the tile additional information according to the sixth embodiment. [Figure 59] FIG. 59 is a block diagram of a coding / decoding system according to the sixth embodiment. [Figure 60] FIG. 60 is a diagram showing an example of the syntax of slice additional information according to the sixth embodiment. [Figure 61] FIG. 61 is a flowchart of the encoding process according to the sixth embodiment. [Figure 62] FIG. 62 is a flowchart of the decoding process according to the sixth embodiment. [Figure 63] FIG. 63 is a flowchart of the encoding process according to the sixth embodiment. [Figure 64] FIG. 64 is a flowchart of the decoding process according to the sixth embodiment. [Figure 65] FIG. 65 is a diagram showing an example of a division method according to the seventh embodiment. [Figure 66] FIG. 66 is a diagram illustrating an example of division of point cloud data according to the seventh embodiment. [Figure 67] FIG. 67 is a diagram illustrating an example of the syntax of the tile additional information according to the seventh embodiment. [Figure 68] FIG. 68 is a diagram showing an example of index information according to the seventh embodiment. [Figure 69] FIG. 69 is a diagram showing an example of a dependency relationship according to the seventh embodiment. In FIG. [Figure 70] FIG. 70 is a diagram showing an example of transmission data according to the seventh embodiment. In FIG. [Figure 71] FIG. 71 is a diagram showing an example of the structure of a NAL unit according to the seventh embodiment. [Figure 72] FIG. 72 is a diagram showing an example of a dependency relationship according to the seventh embodiment. In FIG. [Figure 73] FIG. 73 is a diagram showing an example of a data decoding order according to the seventh embodiment. [Figure 74]FIG. 74 is a diagram showing an example of a dependency relationship according to the seventh embodiment. In FIG. [Figure 75] FIG. 75 is a diagram showing an example of a data decoding order according to the seventh embodiment. [Figure 76] FIG. 76 is a flowchart of the encoding process according to the seventh embodiment. [Figure 77] FIG. 77 is a flowchart of the decoding process according to the seventh embodiment. [Figure 78] FIG. 78 is a flowchart of the encoding process according to the seventh embodiment. [Figure 79] FIG. 79 is a flowchart of the encoding process according to the seventh embodiment. [Figure 80] FIG. 80 is a diagram showing an example of transmission data and reception data according to the seventh embodiment. In FIG. [Figure 81] FIG. 81 is a flowchart of the decoding process according to the seventh embodiment. [Figure 82] FIG. 82 is a diagram showing an example of transmission data and reception data according to the seventh embodiment. In FIG. [Figure 83] FIG. 83 is a flowchart of the decoding process according to the seventh embodiment. [Figure 84] FIG. 84 is a flowchart of the encoding process according to the seventh embodiment. [Figure 85] FIG. 85 is a diagram showing an example of index information according to the seventh embodiment. [Figure 86] FIG. 86 is a diagram showing an example of a dependency relationship according to the seventh embodiment. In FIG. [Figure 87] FIG. 87 is a diagram showing an example of transmission data according to the seventh embodiment. In FIG. [Figure 88] FIG. 88 is a diagram showing an example of transmission data and reception data according to the seventh embodiment. In FIG. [Figure 89] FIG. 89 is a flowchart of the decoding process according to the seventh embodiment. [Figure 90] FIG. 90 is a flowchart of the encoding process according to the seventh embodiment. [Figure 91]FIG. 91 is a flowchart of the decoding process according to the seventh embodiment. [Figure 92] FIG. 92 is a block diagram showing an example of the configuration of a three-dimensional data encoding device according to the eighth embodiment. As shown in FIG. [Figure 93] FIG. 93 is a diagram for explaining an outline of the encoding method performed by the three-dimensional data encoding device according to the eighth embodiment. [Figure 94] FIG. 94 is a diagram for explaining a first example of the position shift according to the eighth embodiment. In FIG. [Figure 95] FIG. 95 is a diagram for explaining a second example of the position shift according to the eighth embodiment. In FIG. [Figure 96] FIG. 96 is a flowchart showing an example of a coding method according to the eighth embodiment. [Figure 97] FIG. 97 is a flowchart showing an example of a decoding method according to the eighth embodiment. [Figure 98] FIG. 98 is a diagram for explaining a third example of the position shift according to the eighth embodiment. In FIG. [Figure 99] FIG. 99 is a flowchart showing an example of a coding method according to the eighth embodiment. [Figure 100] FIG. 100 is a flowchart showing an example of a decoding method according to the eighth embodiment. [Figure 101] FIG. 101 is a diagram for explaining a fourth example of the position shift according to the eighth embodiment. In FIG. [Figure 102] FIG. 102 is a flowchart showing an example of a coding method according to the eighth embodiment. [Figure 103] FIG. 103 is a diagram for explaining a fifth example of the position shift according to the eighth embodiment. In FIG. [Figure 104] FIG. 104 is a diagram illustrating the coding method according to the eighth embodiment. In FIG. [Figure 105] FIG. 105 is a diagram illustrating an example of the syntax of the GPS according to the eighth embodiment. [Fig. 106] FIG. 106 is a diagram illustrating an example of the syntax of a header of location information according to the eighth embodiment. [Figure 107] FIG. 107 is a flowchart showing an example of a coding method for switching processes according to the eighth embodiment. [Figure 108] FIG. 108 is a flowchart showing an example of a decoding method for switching processes according to the eighth embodiment. [Figure 109] FIG. 109 is a diagram showing an example of a data structure of a bit stream according to the eighth embodiment. [Figure 110] FIG. 110 shows an example in which the divided data in FIG. 109 according to the eighth embodiment is organized into frames. [Figure 111] FIG. 111 is a diagram showing another example of the divided regions according to the eighth embodiment. In FIG. [Figure 112] FIG. 112 is a diagram showing another example of the divided regions according to the eighth embodiment. In FIG. [Figure 113] FIG. 113 is a diagram showing another example of the divided regions according to the eighth embodiment. In FIG. [Fig. 114] FIG. 114 is a diagram showing another example of the divided regions according to the eighth embodiment. In FIG. [Figure 115] FIG. 115 is a diagram showing another example of a data structure according to the eighth embodiment. In FIG. [Fig. 116] FIG. 116 is a diagram showing another example of a data structure according to the eighth embodiment. In FIG. [Figure 117] FIG. 117 is a diagram showing another example of a data structure according to the eighth embodiment. In FIG. [Fig. 118] FIG. 118 is a diagram showing another example of a data structure according to the eighth embodiment. In FIG. [Figure 119] FIG. 119 is a diagram showing another example of a data structure according to the eighth embodiment. In FIG. [Figure 120] FIG. 120 is a flowchart of the encoding process according to the eighth embodiment. [Figure 121] FIG. 121 is a flowchart of the decoding process according to the eighth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] A three-dimensional data encoding method according to one embodiment of the present disclosure is a three-dimensional data encoding method for encoding point cloud data indicating a plurality of three-dimensional positions in a three-dimensional space, comprising the steps of: moving the point cloud data by a first movement amount; dividing the three-dimensional space into a plurality of sub-spaces, dividing the point cloud data into a plurality of sub-point cloud data; moving each of the plurality of sub-point cloud data included in the point cloud data after moving the first movement amount by a second movement amount based on the position of the sub-space in which the sub-point cloud data is included; and encoding the plurality of sub-point cloud data after movement to generate a bit stream, wherein the bit stream includes first movement information for calculating the first movement amount and a plurality of second movement information for calculating each of the plurality of second movement amounts by moving the plurality of sub-point cloud data.

[0016] According to this, since the divided sub-point cloud data is moved and then encoded, the amount of information of the position information of each sub-point cloud data can be reduced, and encoding efficiency can be improved.

[0017] For example, the plurality of subspaces may have equal sizes, and each of the plurality of second movement information may include the number of the plurality of subspaces and first identification information for identifying the corresponding subspace.

[0018] This makes it possible to reduce the amount of information in the second movement information, thereby improving the coding efficiency.

[0019] For example, the first identification information may be a Morton order corresponding to each of the plurality of subspaces.

[0020] For example, each of the multiple subspaces may be a space obtained by dividing a single three-dimensional space using an octree, and the bit stream may include second identification information indicating that the multiple subspaces are spaces divided using an octree, and depth information indicating the depth of the octree.

[0021] Therefore, since the point cloud data in a three-dimensional space is divided using an octree, the amount of information of the position information of each sub-point cloud data can be reduced, and the coding efficiency can be improved.

[0022] For example, the division may be performed after the point cloud data is moved by the first movement amount.

[0023] In addition, a three-dimensional data decoding method according to one embodiment of the present disclosure may include decoding from a bit stream a plurality of sub-point cloud data into which point cloud data indicating a plurality of three-dimensional positions is divided by dividing a three-dimensional space into a plurality of subspaces, each of the sub-point cloud data being moved by a first movement amount and a corresponding second movement amount, first movement information for calculating the first movement amount, and a plurality of second movement information for calculating each of the plurality of second movement amounts by which the plurality of sub-point cloud data are moved, and restoring the point cloud data by moving each of the plurality of sub-point cloud data by an amount obtained by adding up the first movement amount and the corresponding second movement amount.

[0024] This makes it possible to correctly decode the point group data using a bitstream with improved coding efficiency.

[0025] For example, the plurality of subspaces may have equal sizes, and each of the plurality of second movement information may include the number of the plurality of subspaces and first identification information for identifying the corresponding subspace.

[0026] For example, the first identification information may be a Morton order corresponding to each of the plurality of subspaces.

[0027] For example, each of the multiple subspaces may be a space obtained by dividing a single three-dimensional space using an octree, and the bit stream may include second identification information indicating that the multiple subspaces are spaces divided using an octree, and depth information indicating the depth of the octree.

[0028] Moreover, a three-dimensional data encoding device according to one embodiment of the present disclosure is a three-dimensional data encoding device that encodes point cloud data indicating a plurality of three-dimensional positions in a three-dimensional space, and includes a processor and a memory, wherein the processor uses the memory to move the point cloud data by a first movement amount, and divides the three-dimensional space into a plurality of sub-spaces to divide the point cloud data into a plurality of sub-point cloud data, and for each of the plurality of sub-point cloud data included in the point cloud data after moving by the first movement amount, moves the sub-point cloud data by a second movement amount based on the position of the sub-space in which the sub-point cloud data is included, and generates a bit stream by encoding the plurality of sub-point cloud data after movement, and the bit stream includes first movement information for calculating the first movement amount and a plurality of second movement information for calculating each of the plurality of second movement amounts by which the plurality of sub-point cloud data is moved.

[0029] According to this, since the divided sub-point cloud data is moved and then encoded, the amount of information of the position information of each sub-point cloud data can be reduced, and encoding efficiency can be improved.

[0030] In addition, a three-dimensional data decoding device according to one embodiment of the present disclosure includes a processor and a memory, and the processor may use the memory to decode from a bit stream a plurality of sub-point cloud data obtained by dividing a three-dimensional space into a plurality of subspaces to divide point cloud data indicating a plurality of three-dimensional positions, each of the sub-point cloud data being moved by a first movement amount and a corresponding second movement amount, first movement information for calculating the first movement amount, and a plurality of second movement information for calculating each of the plurality of second movement amounts by which the plurality of sub-point cloud data has been moved, and restore the point cloud data by moving each of the plurality of sub-point cloud data by an amount obtained by adding the first movement amount and the corresponding second movement amount.

[0031] This makes it possible to correctly decode the point group data using a bitstream with improved coding efficiency.

[0032] These comprehensive or specific aspects may be realized as a system, a method, an integrated circuit, a computer program, or a recording medium such as a computer-readable CD-ROM, or may be realized as any combination of a system, a method, an integrated circuit, a computer program, and a recording medium.

[0033] Hereinafter, the embodiments will be described in detail with reference to the drawings. Note that each of the embodiments described below shows a specific example of the present disclosure. The numerical values, shapes, materials, components, arrangement and connection forms of the components, steps, and order of steps shown in the following embodiments are merely examples and are not intended to limit the present disclosure. In addition, among the components in the following embodiments, components that are not described in an independent claim showing a top concept are described as optional components.

[0034] (Embodiment 1) When using the encoded data of a point cloud in an actual device or service, it is desirable to transmit and receive the necessary information according to the purpose in order to reduce the network bandwidth. However, until now, such a function has not existed in the encoding structure of three-dimensional data, and there has been no encoding method for this purpose.

[0035] In this embodiment, we describe a three-dimensional data encoding method and a three-dimensional data encoding device for providing the function of transmitting and receiving necessary information depending on the application in encoded data of a three-dimensional point cloud, as well as a three-dimensional data decoding method and a three-dimensional data decoding device for decoding the encoded data, a three-dimensional data multiplexing method for multiplexing the encoded data, and a three-dimensional data transmission method for transmitting the encoded data.

[0036] In particular, the first and second encoding methods are currently being considered as methods (encoding schemes) for encoding point cloud data; however, the structure of the encoded data and the method for storing the encoded data in a system format have not been defined, and as things stand, there is a problem that MUX processing (multiplexing) in the encoding unit, or transmission or storage, is not possible.

[0037] Also, there has been no method to date that supports a format in which two codecs, the first encoding method and the second encoding method, are mixed, such as PCC (Point Cloud Compression).

[0038] In this embodiment, a structure of PCC encoded data in which two codecs, a first encoding method and a second encoding method, are mixed, and a method of storing the encoded data in a system format will be described.

[0039] First, the configuration of a three-dimensional data (point cloud data) encoding / decoding system according to this embodiment will be described. Fig. 1 is a diagram showing an example of the configuration of a three-dimensional data encoding / decoding system according to this embodiment. As shown in Fig. 1, the three-dimensional data encoding / decoding system includes a three-dimensional data encoding system 4601, a three-dimensional data decoding system 4602, a sensor terminal 4603, and an external connection unit 4604.

[0040] The three-dimensional data encoding system 4601 generates encoded data or multiplexed data by encoding point cloud data, which is three-dimensional data. The three-dimensional data encoding system 4601 may be a three-dimensional data encoding device realized by a single device, or may be a system realized by multiple devices. The three-dimensional data encoding device may include some of the multiple processing units included in the three-dimensional data encoding system 4601.

[0041] The three-dimensional data encoding system 4601 includes a point cloud data generation system 4611, a presentation unit 4612, an encoding unit 4613, a multiplexing unit 4614, an input / output unit 4615, and a control unit 4616. The point cloud data generation system 4611 includes a sensor information acquisition unit 4617 and a point cloud data generation unit 4618.

[0042] The sensor information acquisition unit 4617 acquires sensor information from the sensor terminal 4603, and outputs the sensor information to the point cloud data generation unit 4618. The point cloud data generation unit 4618 generates point cloud data from the sensor information, and outputs the point cloud data to the encoding unit 4613.

[0043] The presentation unit 4612 presents the sensor information or the point cloud data to the user. For example, the presentation unit 4612 displays information or an image based on the sensor information or the point cloud data.

[0044] The encoding unit 4613 encodes (compresses) the point cloud data, and outputs the obtained encoded data, control information obtained in the encoding process, and other additional information to the multiplexing unit 4614. The additional information includes, for example, sensor information.

[0045] The multiplexing unit 4614 generates multiplexed data by multiplexing the coded data, control information, and additional information input from the coding unit 4613. The format of the multiplexed data is, for example, a file format for storage, or a packet format for transmission.

[0046] The input / output unit 4615 (e.g., a communication unit or an interface) outputs the multiplexed data to the outside. Alternatively, the multiplexed data is stored in a storage unit such as an internal memory. The control unit 4616 (or an application execution unit) controls each processing unit. In other words, the control unit 4616 controls encoding, multiplexing, etc.

[0047] The sensor information may be input to the encoding unit 4613 or the multiplexing unit 4614. Furthermore, the input / output unit 4615 may output the point cloud data or the encoded data directly to the outside.

[0048] The transmission signal (multiplexed data) output from the three-dimensional data encoding system 4601 is input to the three-dimensional data decoding system 4602 via the external connection unit 4604.

[0049] The three-dimensional data decoding system 4602 generates point cloud data, which is three-dimensional data, by decoding the encoded data or multiplexed data. The three-dimensional data decoding system 4602 may be a three-dimensional data decoding device realized by a single device, or may be a system realized by multiple devices. The three-dimensional data decoding device may also include some of the multiple processing units included in the three-dimensional data decoding system 4602.

[0050] The three-dimensional data decoding system 4602 includes a sensor information acquisition unit 4621 , an input / output unit 4622 , a demultiplexing unit 4623 , a decoding unit 4624 , a presentation unit 4625 , a user interface 4626 , and a control unit 4627 .

[0051] The sensor information acquisition unit 4621 acquires sensor information from the sensor terminal 4603 .

[0052] The input / output unit 4622 acquires a transmission signal, decodes multiplexed data (file format or packets) from the transmission signal, and outputs the multiplexed data to the demultiplexer 4623.

[0053] The demultiplexer 4623 obtains the coded data, control information, and additional information from the multiplexed data, and outputs the coded data, control information, and additional information to the decoder 4624.

[0054] The decoding unit 4624 reconstructs the point cloud data by decoding the encoded data.

[0055] The presentation unit 4625 presents the point cloud data to the user. For example, the presentation unit 4625 displays information or an image based on the point cloud data. The user interface 4626 acquires an instruction based on a user's operation. The control unit 4627 (or the application execution unit) controls each processing unit. That is, the control unit 4627 controls demultiplexing, decoding, presentation, etc.

[0056] The input / output unit 4622 may obtain the point cloud data or the encoded data directly from the outside. The presentation unit 4625 may obtain additional information such as sensor information and present information based on the additional information. The presentation unit 4625 may present information based on a user instruction obtained by the user interface 4626.

[0057] The sensor terminal 4603 generates sensor information obtained by a sensor. The sensor terminal 4603 is a terminal equipped with a sensor or a camera, and examples of the sensor terminal include a moving body such as an automobile, a flying object such as an airplane, a mobile terminal, and a camera.

[0058] The sensor information that can be acquired by the sensor terminal 4603 is, for example, (1) the distance between the sensor terminal 4603 and an object, or the reflectance of the object, obtained from a LIDAR, millimeter wave radar, or an infrared sensor, and (2) the distance between a camera and an object, or the reflectance of the object, obtained from a plurality of monocular camera images or stereo camera images. The sensor information may also include the attitude, direction, gyro (angular velocity), position (GPS information or altitude), speed, acceleration, etc. of the sensor. The sensor information may also include temperature, air pressure, humidity, magnetism, etc.

[0059] The external connection unit 4604 is realized by an integrated circuit (LSI or IC), an external storage unit, communication with a cloud server via the Internet, broadcasting, or the like.

[0060] Next, the point cloud data will be described. Fig. 2 is a diagram showing the configuration of the point cloud data. Fig. 3 is a diagram showing an example of the configuration of a data file in which information on the point cloud data is written.

[0061] Point cloud data includes data on multiple points. The data on each point includes position information (three-dimensional coordinates) and attribute information for that position information. A collection of multiple points is called a point cloud. For example, a point cloud may represent the three-dimensional shape of an object.

[0062] Position information such as three-dimensional coordinates is sometimes called geometry. Data for each point may include attribute information of multiple attribute types. The attribute types may be, for example, color or reflectance.

[0063] One piece of attribute information may be associated with one piece of location information, or multiple pieces of attribute information having different attribute types may be associated with one piece of location information, or multiple pieces of attribute information of the same attribute type may be associated with one piece of location information.

[0064] The configuration example of the data file shown in FIG. 3 is an example in which position information and attribute information correspond one-to-one, and shows the position information and attribute information of N points that make up the point cloud data.

[0065] The position information is, for example, information on three axes, x, y, and z. The attribute information is, for example, RGB color information. A typical data file is a ply file.

[0066] Next, the types of point cloud data will be described. Fig. 4 is a diagram showing the types of point cloud data. As shown in Fig. 4, point cloud data includes static objects and dynamic objects.

[0067] A static object is 3D point cloud data at any time (a certain time). A dynamic object is 3D point cloud data that changes over time. Hereinafter, 3D point cloud data at a certain time will be referred to as a PCC frame, or a frame.

[0068] The object may be a point cloud whose area is restricted to a certain extent, such as ordinary video data, or a large-scale point cloud whose area is not restricted, such as map information.

[0069] Also, there may be point cloud data of various densities, and there may be sparse point cloud data and dense point cloud data.

[0070] The details of each processing unit will be described below. The sensor information is acquired by various methods such as a distance sensor such as a LIDAR or a range finder, a stereo camera, or a combination of multiple monocular cameras. The point cloud data generation unit 4618 generates point cloud data based on the sensor information acquired by the sensor information acquisition unit 4617. The point cloud data generation unit 4618 generates position information as point cloud data, and adds attribute information for the position information to the position information.

[0071] The point cloud data generating unit 4618 may process the point cloud data when generating the position information or adding the attribute information. For example, the point cloud data generating unit 4618 may reduce the amount of data by deleting point clouds with overlapping positions. In addition, the point cloud data generating unit 4618 may convert the position information (position shift, rotation, normalization, etc.) or render the attribute information.

[0072] In FIG. 1, the point cloud data generation system 4611 is included in the three-dimensional data encoding system 4601, but it may be provided independently outside the three-dimensional data encoding system 4601.

[0073] The encoding unit 4613 generates encoded data by encoding the point cloud data based on a predefined encoding method. There are two main types of encoding methods: the first is an encoding method using position information, and this encoding method will be referred to as the first encoding method hereinafter; the second is an encoding method using a video codec, and this encoding method will be referred to as the second encoding method hereinafter.

[0074] The decoding unit 4624 decodes the encoded data based on a predefined encoding method to decode the point group data.

[0075] The multiplexing unit 4614 generates multiplexed data by multiplexing the encoded data using an existing multiplexing method. The generated multiplexed data is transmitted or stored. In addition to the PCC encoded data, the multiplexing unit 4614 multiplexes other media such as video, audio, subtitles, applications, and files, or reference time information. The multiplexing unit 4614 may further multiplex attribute information related to sensor information or point cloud data.

[0076] Multiplexing methods or file formats include ISOBMFF, MPEG-DASH, which is an ISOBMFF-based transmission method, MMT, MPEG-2 TS Systems, and RMP.

[0077] The demultiplexer 4623 extracts the PCC encoded data, other media, time information, and the like from the multiplexed data.

[0078] The input / output unit 4615 transmits the multiplexed data using a method suited to a transmission medium or a storage medium, such as broadcasting or communication. The input / output unit 4615 may communicate with other devices via the Internet, or may communicate with a storage unit such as a cloud server.

[0079] The communication protocol used may be http, ftp, TCP, UDP, etc. A PULL type communication method or a PUSH type communication method may be used.

[0080] Either wired transmission or wireless transmission may be used. For wired transmission, Ethernet (registered trademark), USB, RS-232C, HDMI (registered trademark), coaxial cable, etc. are used. For wireless transmission, wireless LAN, Wi-Fi (registered trademark), Bluetooth (registered trademark), millimeter wave, etc. are used.

[0081] As a broadcasting system, for example, DVB-T2, DVB-S2, DVB-C2, ATSC3.0, or ISDB-S3 is used.

[0082] Fig. 5 is a diagram showing a configuration of a first encoding unit 4630 which is an example of the encoding unit 4613 that performs encoding using the first encoding method. Fig. 6 is a block diagram of the first encoding unit 4630. The first encoding unit 4630 generates encoded data (encoded stream) by encoding point cloud data using the first encoding method. The first encoding unit 4630 includes a position information encoding unit 4631, an attribute information encoding unit 4632, an additional information encoding unit 4633, and a multiplexing unit 4634.

[0083] The first encoding unit 4630 has a feature of performing encoding in consideration of a three-dimensional structure. Also, the first encoding unit 4630 has a feature that the attribute information encoding unit 4632 performs encoding using information obtained from the position information encoding unit 4631. The first encoding method is also called GPCC (Geometry based PCC).

[0084] The point cloud data is PCC point cloud data such as a PLY file, or PCC point cloud data generated from sensor information, and includes position information (Position), attribute information (Attribute), and other additional information (MetaData). The position information is input to a position information encoding unit 4631, the attribute information is input to an attribute information encoding unit 4632, and the additional information is input to an additional information encoding unit 4633.

[0085] The position information encoding unit 4631 generates encoded position information (Compressed Geometry) that is encoded data by encoding the position information. For example, the position information encoding unit 4631 encodes the position information using an N-ary tree structure such as an octet tree. Specifically, in the octet tree, the target space is divided into eight nodes (subspaces), and 8-bit information (occupancy code) indicating whether or not a point cloud is included in each node is generated. In addition, the node that includes the point cloud is further divided into eight nodes, and 8-bit information indicating whether or not a point cloud is included in each of the eight nodes is generated. This process is repeated until the number of point clouds included in a predetermined hierarchy or node is equal to or less than a threshold value.

[0086] The attribute information encoding unit 4632 generates encoded attribute information (Compressed Attribute) that is encoded data by encoding using the configuration information generated by the position information encoding unit 4631. For example, the attribute information encoding unit 4632 determines a reference point (reference node) to be referenced in encoding a target point (target node) to be processed based on the octree structure generated by the position information encoding unit 4631. For example, the attribute information encoding unit 4632 refers to a node, among peripheral nodes or adjacent nodes, whose parent node in the octree is the same as that of the target node. Note that the method of determining the reference relationship is not limited to this.

[0087] Furthermore, the encoding process of the attribute information may include at least one of a quantization process, a prediction process, and an arithmetic coding process. In this case, the reference means using a reference node to calculate a predicted value of the attribute information, or using a state of the reference node (e.g., occupancy information indicating whether or not a point group is included in the reference node) to determine a parameter of the encoding. For example, the parameter of the encoding is a quantization parameter in the quantization process, or a context in the arithmetic coding.

[0088] The additional information encoding unit 4633 generates encoded additional information (Compressed MetaData) that is encoded data by encoding compressible data from the additional information.

[0089] The multiplexing unit 4634 multiplexes the encoding position information, the encoding attribute information, the encoding additional information, and other additional information to generate an encoded stream (Compressed Stream) that is encoded data. The generated encoded stream is output to a processing unit of a system layer (not shown).

[0090] Next, a first decoding unit 4640 which is an example of the decoding unit 4624 that performs decoding of the first encoding method will be described. FIG. 7 is a diagram showing a configuration of the first decoding unit 4640. FIG. 8 is a block diagram of the first decoding unit 4640. The first decoding unit 4640 generates point group data by decoding, by the first encoding method, encoded data (encoded stream) encoded by the first encoding method. The first decoding unit 4640 includes a demultiplexing unit 4641, a position information decoding unit 4642, an attribute information decoding unit 4643, and an additional information decoding unit 4644.

[0091] A coded stream (compressed stream), which is coded data, is input to the first decoding unit 4640 from a processing unit in a system layer (not shown).

[0092] The demultiplexer 4641 separates the encoded position information (Compressed Geometry), the encoded attribute information (Compressed Attribute), the encoded additional information (Compressed MetaData), and other additional information from the encoded data.

[0093] The position information decoding unit 4642 generates position information by decoding the encoded position information. For example, the position information decoding unit 4642 restores the position information of a point group represented by three-dimensional coordinates from the encoded position information represented by an N-ary tree structure such as an octree.

[0094] The attribute information decoding unit 4643 decodes the encoded attribute information based on the configuration information generated by the position information decoding unit 4642. For example, the attribute information decoding unit 4643 determines a reference point (reference node) to be referenced in decoding a target point (target node) to be processed based on the octree structure obtained by the position information decoding unit 4642. For example, the attribute information decoding unit 4643 refers to a node, among peripheral nodes or adjacent nodes, whose parent node in the octree is the same as that of the target node. Note that the method of determining the reference relationship is not limited to this.

[0095] In addition, the decoding process of the attribute information may include at least one of an inverse quantization process, a prediction process, and an arithmetic decoding process. In this case, the reference means using a reference node to calculate a predicted value of the attribute information, or using a state of the reference node (e.g., occupancy information indicating whether or not a point group is included in the reference node) to determine a parameter of the decoding. For example, the parameter of the decoding is a quantization parameter in the inverse quantization process, or a context in the arithmetic decoding.

[0096] The additional information decoding unit 4644 generates additional information by decoding the encoded additional information. The first decoding unit 4640 uses the additional information required for decoding the position information and attribute information during decoding, and outputs the additional information required for an application to the outside.

[0097] Next, a second encoding unit 4650, which is an example of the encoding unit 4613 that performs encoding by the second encoding method, will be described. Fig. 9 is a diagram showing a configuration of the second encoding unit 4650. Fig. 10 is a block diagram of the second encoding unit 4650.

[0098] The second encoding unit 4650 generates encoded data (encoded stream) by encoding the point cloud data by a second encoding method. The second encoding unit 4650 includes an additional information generating unit 4651, a position image generating unit 4652, an attribute image generating unit 4653, a video encoding unit 4654, an additional information encoding unit 4655, and a multiplexing unit 4656.

[0099] The second encoding unit 4650 has a feature of generating a position image and an attribute image by projecting a three-dimensional structure onto a two-dimensional image, and encoding the generated position image and attribute image using an existing video encoding method. The second encoding method is also called VPCC (Video based PCC).

[0100] The point cloud data is PCC point cloud data such as a PLY file, or PCC point cloud data generated from sensor information, and includes position information (Position), attribute information (Attribute), and other additional information (MetaData).

[0101] The additional information generating unit 4651 generates map information of a plurality of two-dimensional images by projecting a three-dimensional structure onto the two-dimensional images.

[0102] The position image generating unit 4652 generates a position image (Geometry Image) based on the position information and the map information generated by the additional information generating unit 4651. This position image is, for example, a distance image in which distance (Depth) is indicated as a pixel value. Note that this distance image may be an image in which a plurality of point clouds are viewed from one viewpoint (an image in which a plurality of point clouds are projected onto one two-dimensional plane), a plurality of images in which a plurality of point clouds are viewed from multiple viewpoints, or a single image in which these multiple images are integrated.

[0103] The attribute image generating unit 4653 generates an attribute image based on the attribute information and the map information generated by the additional information generating unit 4651. This attribute image is, for example, an image in which the attribute information (for example, color (RGB)) is indicated as pixel values. Note that this image may be an image in which multiple point clouds are viewed from one viewpoint (an image in which multiple point clouds are projected onto one two-dimensional plane), or multiple images in which multiple point clouds are viewed from multiple viewpoints, or a single image in which these multiple images are integrated.

[0104] The video encoding unit 4654 generates an encoded position image (Compressed Geometry Image) and an encoded attribute image (Compressed Attribute Image), which are encoded data, by encoding the position image and the attribute image using a video encoding method. Note that any known encoding method may be used as the video encoding method. For example, the video encoding method is AVC, HEVC, or the like.

[0105] The additional information encoding unit 4655 generates encoded additional information (Compressed MetaData) by encoding the additional information and map information included in the point cloud data.

[0106] The multiplexing unit 4656 multiplexes the encoding position image, the encoding attribute image, the encoding additional information, and other additional information to generate an encoded stream (Compressed Stream) that is encoded data. The generated encoded stream is output to a processing unit of a system layer (not shown).

[0107] Next, a second decoding unit 4660 which is an example of the decoding unit 4624 that performs decoding of the second encoding method will be described. FIG. 11 is a diagram showing a configuration of the second decoding unit 4660. FIG. 12 is a block diagram of the second decoding unit 4660. The second decoding unit 4660 generates point group data by decoding, by the second encoding method, encoded data (encoded stream) encoded by the second encoding method. The second decoding unit 4660 includes a demultiplexing unit 4661, a video decoding unit 4662, an additional information decoding unit 4663, a position information generating unit 4664, and an attribute information generating unit 4665.

[0108] A compressed stream, which is encoded data, is input to the second decoding unit 4660 from a processing unit in a system layer (not shown).

[0109] The demultiplexer 4661 separates the encoded position image (Compressed Geometry Image), the encoded attribute image (Compressed Attribute Image), the encoded additional information (Compressed MetaData), and other additional information from the encoded data.

[0110] The video decoding unit 4662 generates a position image and an attribute image by decoding the encoded position image and the encoded attribute image using a video encoding method. Note that any known encoding method may be used as the video encoding method. For example, the video encoding method is AVC or HEVC.

[0111] The additional information decoding unit 4663 decodes the encoded additional information to generate additional information including map information and the like.

[0112] The position information generating unit 4664 generates position information using the position image and map information. The attribute information generating unit 4665 generates attribute information using the attribute image and map information.

[0113] The second decoding unit 4660 uses the additional information necessary for decoding during decoding, and outputs the additional information necessary for an application to the outside.

[0114] The problems with the PCC encoding method will be described below. Fig. 13 is a diagram showing a protocol stack related to PCC encoded data. Fig. 13 shows an example in which other media data such as video (e.g., HEVC) or audio is multiplexed with the PCC encoded data and transmitted or stored.

[0115] The multiplexing method and file format have the function of multiplexing various encoded data and transmitting or storing them. In order to transmit or store the encoded data, the encoded data must be converted into the format of the multiplexing method. For example, HEVC specifies a technology for storing encoded data in a data structure called a NAL unit and storing the NAL unit in ISOBMFF.

[0116] Meanwhile, a first encoding method (Codec1) and a second encoding method (Codec2) are currently being considered as methods for encoding point cloud data. However, the structure of the encoded data and the method for storing the encoded data in a system format have not been defined, which poses the problem that MUX processing (multiplexing) in the encoding unit, transmission, and storage cannot be performed as is.

[0117] In the following description, unless a specific encoding method is specified, it refers to either the first encoding method or the second encoding method.

[0118] (Embodiment 2) In this embodiment, a method for storing NAL units in an ISOBMFF file will be described.

[0119] ISOBMFF (ISO based media file format) is a file format standard defined in ISO / IEC 14496-12. ISOBMFF specifies a format that can store multiplexed media such as video, audio, and text, and is a media-independent standard.

[0120] The basic structure (file) of ISOBMFF is explained. The basic unit in ISOBMFF is a box. A box consists of type, length, and data, and a file is a collection of boxes of various types.

[0121] 14 is a diagram showing the basic structure (file) of ISOBMFF. An ISOBMFF file mainly includes boxes such as ftyp, which indicates the brand of the file with 4CC (4-character code), moov, which stores metadata such as control information, and mdat, which stores data.

[0122] A method of storing each medium in an ISOBMFF file is specified separately, and for example, a method of storing AVC video and HEVC video is specified in ISO / IEC14496-15. Here, it is considered that the function of ISOBMFF is extended and used to accumulate or transmit PCC encoded data, but there is no provision yet for storing PCC encoded data in an ISOBMFF file. Therefore, in this embodiment, a method of storing PCC encoded data in an ISOBMFF file will be described.

[0123] 15 is a diagram showing a protocol stack when a NAL unit common to PCC codecs is stored in an ISOBMFF file. Here, a NAL unit common to PCC codecs is stored in an ISOBMFF file. Although the NAL unit is common to PCC codecs, since multiple PCC codecs are stored in the NAL unit, it is desirable to define a storage method (Carriage of Codec1, Carriage of Codec2) according to each codec.

[0124] Next, a method of storing a common PCC NAL unit that supports multiple PCC codecs in an ISOBMFF file will be described. Fig. 16 is a diagram showing an example of storing a common PCC NAL unit in an ISOBMFF file in a storage method for codec 1 (Carriage of Codec1). Fig. 17 is a diagram showing an example of storing a common PCC NAL unit in an ISOBMFF file in a storage method for codec 2 (Carriage of Codec2).

[0125] Here, ftyp is important information for identifying the file format, and a different identifier is defined for ftyp for each codec. When PCC encoded data encoded with a first encoding method (encoding format) is stored in a file, ftyp=pcc1 is set. When PCC encoded data encoded with a second encoding method is stored in a file, ftyp=pcc2 is set.

[0126] Here, pcc1 indicates that PCC codec 1 (first encoding method) is used. pcc2 indicates that PCC codec 2 (second encoding method) is used. In other words, pcc1 and pcc2 indicate that the data is PCC (coded data of three-dimensional data (point cloud data)), and indicate PCC codecs (first and second encoding methods).

[0127] A method of storing NAL units in an ISOBMFF file will be described below. The multiplexing unit analyzes the NAL unit header, and if pcc_codec_type=Codec1, writes pcc1 in ftyp of ISOBMFF.

[0128] In addition, the multiplexing unit analyzes the NAL unit header, and if pcc_codec_type=Codec2, writes pcc2 in the ftyp of ISOBMFF.

[0129] Furthermore, if pcc_nal_unit_type is metadata, the multiplexing unit stores the NAL unit in a predetermined manner, for example, in moov or mdat. If pcc_nal_unit_type is data, the multiplexing unit stores the NAL unit in a predetermined manner, for example, in moov or mdat.

[0130] For example, the multiplexing unit may store the NAL unit size in the NAL unit in the same manner as in HEVC.

[0131] This storage method makes it possible to determine whether the PCC encoded data has been encoded by the first encoding method or the second encoding method by analyzing the ftyp included in the file in the demultiplexer (system layer). Furthermore, as described above, by determining whether the PCC encoded data has been encoded by the first encoding method or the second encoding method, it is possible to extract encoded data encoded by one of the encoding methods from data in which encoded data encoded by both encoding methods are mixed. This makes it possible to reduce the amount of data transmitted when transmitting encoded data. Furthermore, this storage method makes it possible to use a common data format for the first encoding method and the second encoding method without setting different data (file) formats.

[0132] In addition, when codec identification information is indicated in metadata of the system layer, such as ftyp in ISOBMFF, the multiplexing unit may store the NAL unit from which pcc_nal_unit_type has been deleted in the ISOBMFF file.

[0133] Next, the configuration and operation of the multiplexing unit provided in the three-dimensional data encoding system (three-dimensional data encoding device) of this embodiment, and the demultiplexing unit provided in the three-dimensional data decoding system (three-dimensional data decoding device) of this embodiment will be described.

[0134] Fig. 18 is a diagram showing a configuration of the first multiplexing unit 4710. The first multiplexing unit 4710 includes a file conversion unit 4711 that generates multiplexed data (file) by storing the coded data and control information (NAL units) generated by the first coding unit 4630 in an ISOBMFF file. This first multiplexing unit 4710 is included in the multiplexing unit 4614 shown in Fig. 1, for example.

[0135] Fig. 19 is a diagram showing a configuration of the first demultiplexing unit 4720. The first demultiplexing unit 4720 includes a file inverse conversion unit 4721 that acquires coded data and control information (NAL units) from multiplexed data (file) and outputs the acquired coded data and control information to the first decoding unit 4640. This first demultiplexing unit 4720 is included in the demultiplexing unit 4623 shown in Fig. 1, for example.

[0136] Fig. 20 is a diagram showing a configuration of the second multiplexing unit 4730. The second multiplexing unit 4730 includes a file conversion unit 4731 that generates multiplexed data (file) by storing the coded data and control information (NAL units) generated by the second coding unit 4650 in an ISOBMFF file. This second multiplexing unit 4730 is included in the multiplexing unit 4614 shown in Fig. 1, for example.

[0137] Fig. 21 is a diagram showing a configuration of the second demultiplexing unit 4740. The second demultiplexing unit 4740 includes a file inverse conversion unit 4741 that acquires coded data and control information (NAL units) from multiplexed data (file) and outputs the acquired coded data and control information to the second decoding unit 4660. This second demultiplexing unit 4740 is included in the demultiplexing unit 4623 shown in Fig. 1, for example.

[0138] 22 is a flowchart of the multiplexing process by the first multiplexing unit 4710. First, the first multiplexing unit 4710 analyzes pcc_codec_type included in the NAL unit header to determine whether the codec being used is the first encoding method or the second encoding method (S4701).

[0139] If pcc_codec_type indicates the second encoding method (second encoding method in S4702), the first multiplexing unit 4710 does not process the NAL unit (S4703).

[0140] On the other hand, if pcc_codec_type indicates the second encoding method (first encoding method in S4702), the first multiplexing unit 4710 writes pcc1 in ftyp (S4704). That is, the first multiplexing unit 4710 writes information indicating that data encoded by the first encoding method is stored in the file in ftyp.

[0141] Next, the first multiplexing unit 4710 analyzes pcc_nal_unit_type included in the NAL unit header, and stores the data in a box (moov, mdat, or the like) in a predetermined method according to the data type indicated by pcc_nal_unit_type (S4705).Then, the first multiplexing unit 4710 creates an ISOBMFF file including the ftyp and the box (S4706).

[0142] 23 is a flowchart of the multiplexing process by the second multiplexing unit 4730. First, the second multiplexing unit 4730 analyzes pcc_codec_type included in the NAL unit header to determine whether the codec being used is the first encoding method or the second encoding method (S4711).

[0143] When pcc_unit_type indicates the second encoding method (second encoding method in S4712), the second multiplexing unit 4730 writes pcc2 in ftyp (S4713). That is, the second multiplexing unit 4730 writes information indicating that data encoded by the second encoding method is stored in the file in ftyp.

[0144] Next, the second multiplexing unit 4730 analyzes pcc_nal_unit_type included in the NAL unit header, and stores the data in a box (moov, mdat, or the like) in a predetermined method according to the data type indicated by pcc_nal_unit_type (S4714).Then, the second multiplexing unit 4730 creates an ISOBMFF file including the ftyp and the box (S4715).

[0145] On the other hand, if pcc_unit_type indicates the first encoding method (first encoding method in S4712), the second multiplexing unit 4730 does not process the NAL unit (S4716).

[0146] The above process shows an example of encoding the PCC data by either the first encoding method or the second encoding method. The first multiplexing unit 4710 and the second multiplexing unit 4730 store the desired NAL unit in a file by identifying the codec type of the NAL unit. If the PCC codec identification information is included in addition to the NAL unit header, the first multiplexing unit 4710 and the second multiplexing unit 4730 may identify the codec type (the first encoding method or the second encoding method) in steps S4701 and S4711 using the PCC codec identification information included in addition to the NAL unit header.

[0147] Furthermore, when storing the data in a file in steps S4706 and S4714, the first multiplexing unit 4710 and the second multiplexing unit 4730 may delete pcc_nal_unit_type from the NAL unit header before storing the data in the file.

[0148] 24 is a flowchart showing the processing by the first demultiplexing unit 4720 and the first decoding unit 4640. First, the first demultiplexing unit 4720 analyzes ftyp included in the ISOBMFF file (S4721). If the codec indicated by ftyp is the second encoding method (pcc2) (second encoding method in S4722), the first demultiplexing unit 4720 determines that the data included in the payload of the NAL unit is data encoded by the second encoding method (S4723). In addition, the first demultiplexing unit 4720 conveys the result of the determination to the first decoding unit 4640. The first decoding unit 4640 does not process the NAL unit (S4724).

[0149] On the other hand, if the codec indicated by ftyp is the first encoding method (pcc1) (first encoding method in S4722), the first demultiplexing unit 4720 determines that the data included in the payload of the NAL unit is data encoded by the first encoding method (S4725). In addition, the first demultiplexing unit 4720 conveys the result of the determination to the first decoding unit 4640.

[0150] The first decoding unit 4640 identifies the data by determining that the pcc_nal_unit_type included in the NAL unit header is an identifier of the NAL unit for the first encoding method (S4726).Then, the first decoding unit 4640 decodes the PCC data using the decoding process of the first encoding method (S4727).

[0151] 25 is a flowchart showing the processing by the second demultiplexing unit 4740 and the second decoding unit 4660. First, the second demultiplexing unit 4740 analyzes ftyp included in the ISOBMFF file (S4731). If the codec indicated by ftyp is the second encoding method (pcc2) (second encoding method in S4732), the second demultiplexing unit 4740 determines that the data included in the payload of the NAL unit is data encoded by the second encoding method (S4733). In addition, the second demultiplexing unit 4740 conveys the result of the determination to the second decoding unit 4660.

[0152] The second decoding unit 4660 identifies the data by determining that the pcc_nal_unit_type included in the NAL unit header is an identifier of a NAL unit for the second encoding method (S4734).Then, the second decoding unit 4660 decodes the PCC data using the decoding process for the second encoding method (S4735).

[0153] On the other hand, if the codec indicated by ftyp is the first encoding method (pcc1) (first encoding method in S4732), the second demultiplexing unit 4740 determines that the data included in the payload of the NAL unit is data encoded by the first encoding method (S4736). In addition, the second demultiplexing unit 4740 conveys the result of the determination to the second decoding unit 4660. The second decoding unit 4660 does not process the NAL unit (S4737).

[0154] In this way, for example, by identifying the codec type of the NAL unit in the first demultiplexing unit 4720 or the second demultiplexing unit 4740, the codec type can be identified at an early stage. Furthermore, the desired NAL unit can be input to the first decoding unit 4640 or the second decoding unit 4660, and unnecessary NAL units can be removed. In this case, the process of analyzing the codec identification information in the first decoding unit 4640 or the second decoding unit 4660 may become unnecessary. Note that the first decoding unit 4640 or the second decoding unit 4660 may perform the process of analyzing the codec identification information by referring to the NAL unit type again.

[0155] In addition, if the first multiplexing unit 4710 or the second multiplexing unit 4730 removes pcc_nal_unit_type from the NAL unit header, the first demultiplexing unit 4720 or the second demultiplexing unit 4740 may add pcc_nal_unit_type to the NAL unit and then output it to the first decoding unit 4640 or the second decoding unit 4660.

[0156] (Embodiment 3) This embodiment will describe a multiplexing unit and a demultiplexing unit corresponding to the encoding unit 4670 and the decoding unit 4680 that support a plurality of codecs, as described in Embodiment 1. Fig. 26 is a diagram showing configurations of the encoding unit 4670 and the third multiplexing unit 4750 according to this embodiment.

[0157] The encoding unit 4670 encodes the point cloud data using either one or both of the first and second encoding methods. The encoding unit 4670 may switch the encoding method (the first and second encoding methods) in units of point cloud data or in units of frames. The encoding unit 4670 may also switch the encoding method in units that can be encoded.

[0158] The encoding unit 4670 generates encoded data (encoded stream) including identification information of the PCC codec.

[0159] The third multiplexing unit 4750 includes a file conversion unit 4751. The file conversion unit 4751 converts the NAL units output from the encoding unit 4670 into a PCC data file. The file conversion unit 4751 analyzes the codec identification information included in the NAL unit header, and determines whether the PCC encoded data is data encoded by a first encoding method, data encoded by a second encoding method, or data encoded by both methods. The file conversion unit 4751 writes a brand name capable of identifying the codec in ftyp. For example, when indicating that the data is encoded by both methods, pcc3 is written in ftyp.

[0160] If the encoding unit 4670 describes identification information of the PCC codec outside the NAL unit, the file conversion unit 4751 may determine the PCC codec (encoding method) using the identification information.

[0161] FIG. 27 is a diagram showing the configuration of the third demultiplexing unit 4760 and the decoding unit 4680 according to the present embodiment.

[0162] The third demultiplexing unit 4760 includes a file inverse conversion unit 4761. The file inverse conversion unit 4761 analyzes the ftyp included in the file, and determines whether the PCC encoded data is data encoded by the first encoding method, data encoded by the second encoding method, or data encoded by both methods.

[0163] When the PCC encoded data is encoded by one of the encoding methods, the data is input to the corresponding decoding unit of the first decoding unit 4640 or the second decoding unit 4660, and the data is not input to the other decoding unit. When the PCC encoded data is encoded by both encoding methods, the data is input to the decoding unit 4680 that supports both methods.

[0164] The decoding unit 4680 decodes the PCC encoded data using either or both of the first encoding method and the second encoding method.

[0165] FIG. 28 is a flowchart showing processing by the third multiplexing section 4750 according to this embodiment.

[0166] First, the third multiplexing unit 4750 analyzes the pcc_codec_type included in the NAL unit header to determine whether the codec being used is the first encoding method, the second encoding method, or both the first encoding method and the second encoding method (S4741).

[0167] If the second encoding method is used (Yes in S4742 and the second encoding method in S4743), the third multiplexing unit 4750 writes pcc2 in ftyp (S4744). That is, the third multiplexing unit 4750 writes information indicating that data encoded by the second encoding method is stored in the file in ftyp.

[0168] Next, the third multiplexing unit 4750 analyzes pcc_nal_unit_type included in the NAL unit header, and stores the data in a box (moov, mdat, or the like) in a predetermined method according to the data type indicated by pcc_unit_type (S4745).Then, the third multiplexing unit 4750 creates an ISOBMFF file including the above ftyp and the above box (S4746).

[0169] On the other hand, if the first encoding method is used (Yes in S4742 and the first encoding method in S4743), the third multiplexing unit 4750 writes pcc1 in ftyp (S4747). That is, the third multiplexing unit 4750 writes information indicating that data encoded by the first encoding method is stored in the file in ftyp.

[0170] Next, the third multiplexing unit 4750 analyzes pcc_nal_unit_type included in the NAL unit header, and stores the data in a box (moov, mdat, or the like) in a predetermined method according to the data type indicated by pcc_unit_type (S4748).Then, the third multiplexing unit 4750 creates an ISOBMFF file including the above ftyp and the above box (S4746).

[0171] On the other hand, when both the first encoding method and the second encoding method are used (No in S4742), the third multiplexing unit 4750 writes pcc3 in ftyp (S4749). That is, the third multiplexing unit 4750 writes information indicating that data encoded by both encoding methods is stored in the file in ftyp.

[0172] Next, the third multiplexing unit 4750 analyzes pcc_nal_unit_type included in the NAL unit header, and stores the data in a box (moov, mdat, or the like) in a predetermined method according to the data type indicated by pcc_unit_type (S4750).Then, the third multiplexing unit 4750 creates an ISOBMFF file including the above ftyp and the above box (S4746).

[0173] 29 is a flowchart showing the processing by the third demultiplexing unit 4760 and the decoding unit 4680. First, the third demultiplexing unit 4760 analyzes ftyp included in the ISOBMFF file (S4761). If the codec indicated by ftyp is the second encoding method (pcc2) (Yes in S4762 and the second encoding method in S4763), the third demultiplexing unit 4760 determines that the data included in the payload of the NAL unit is data encoded by the second encoding method (S4764). In addition, the third demultiplexing unit 4760 conveys the result of the determination to the decoding unit 4680.

[0174] The decoding unit 4680 identifies the data by determining that the pcc_nal_unit_type included in the NAL unit header is an identifier of a NAL unit for the second encoding method (S4765). Then, the decoding unit 4680 decodes the PCC data using the decoding process for the second encoding method (S4766).

[0175] On the other hand, if the codec indicated by ftyp is the first encoding method (pcc1) (Yes in S4762 and the first encoding method in S4763), the third demultiplexing unit 4760 determines that the data included in the payload of the NAL unit is data encoded by the first encoding method (S4767). In addition, the third demultiplexing unit 4760 conveys the result of the determination to the decoding unit 4680.

[0176] The decoding unit 4680 identifies the data by determining that pcc_nal_unit_type included in the NAL unit header is an identifier of a NAL unit for the first encoding method (S4768). Then, the decoding unit 4680 decodes the PCC data using the decoding process for the first encoding method (S4769).

[0177] On the other hand, if ftyp indicates that both encoding methods are used (pcc3) (No in S4762), the third demultiplexing unit 4760 determines that the data included in the payload of the NAL unit is data encoded by both the first encoding method and the second encoding method (S4770). In addition, the third demultiplexing unit 4760 conveys the result of the determination to the decoding unit 4680.

[0178] The decoding unit 4680 identifies the data by determining that pcc_nal_unit_type included in the NAL unit header is an identifier of the NAL unit for the codec described in pcc_codec_type (S4771). Then, the decoding unit 4680 decodes the PCC data using the decoding processes of both encoding methods (S4772). That is, the decoding unit 4680 decodes data encoded by a first encoding method using the decoding process of the first encoding method, and decodes data encoded by a second encoding method using the decoding process of the second encoding method.

[0179] A modified example of this embodiment will be described below. As the type of brand indicated in ftyp, the following types may be indicated by the identification information. Also, a combination of the following types may be indicated by the identification information.

[0180] The identification information may indicate whether an object in the original data before PCC encoding is a point cloud with a restricted area or a large-scale point cloud with no restricted area such as map information.

[0181] The identification information may indicate whether the original data before PCC encoding is a static object or a dynamic object.

[0182] As described above, the identification information may indicate whether the PCC encoded data is data encoded using a first encoding method or data encoded using a second encoding method.

[0183] The identification information may indicate an algorithm used in the PCC encoding, where the algorithm is, for example, an encoding method that can be used in the first encoding method or the second encoding method.

[0184] The identification information may indicate different storage methods of the PCC encoded data in the ISOBMFF file, for example, the identification information may indicate whether the storage method used is a storage method for storage or a storage method for real-time transmission such as dynamic streaming.

[0185] Although the second and third embodiments have been described with reference to an example in which ISOBMFF is used as the file format, other formats may be used. For example, the same method as in the present embodiment may be used when storing PCC encoded data in MPEG-2 TS Systems, MPEG-DASH, MMT, or RMP.

[0186] In the above example, metadata such as identification information is stored in ftyp, but the metadata may be stored in a location other than ftyp. For example, the metadata may be stored in moov.

[0187] As described above, the three-dimensional data storage device (or the three-dimensional data multiplexing device, or the three-dimensional data encoding device) performs the process shown in FIG.

[0188] First, the three-dimensional data storage device (including, for example, the first multiplexing unit 4710, the second multiplexing unit 4730, or the third multiplexing unit 4750) acquires one or more units (for example, NAL units) in which an encoded stream in which point cloud data is encoded is stored (S4781). Next, the three-dimensional data storage device stores the one or more units in a file (for example, an ISOBMFF file) (S4782). In addition, in the storage (S4782), the three-dimensional data storage device stores information (for example, pcc1, pcc2, or pcc3) indicating that the data stored in the file is data in which point cloud data is encoded, in control information (for example, ftyp) of the file.

[0189] According to this, in a device that processes a file generated by the three-dimensional data storage device, it is possible to refer to the control information of the file and quickly determine whether the data stored in the file is encoded data of point cloud data or not, thereby realizing a reduction in the amount of processing of the device or an increase in the processing speed.

[0190] For example, the information further indicates which of the first and second encoding methods was used to encode the point cloud data. Note that the fact that the data stored in the file is data obtained by encoding the point cloud data and which of the first and second encoding methods was used to encode the point cloud data may be indicated by a single piece of information or may be indicated by different pieces of information.

[0191] According to this, a device that processes a file generated by the three-dimensional data storage device can refer to the control information of the file and quickly determine the codec used for the data stored in the file, thereby reducing the amount of processing of the device and speeding up the processing.

[0192] For example, the first encoding method is a method (GPCC) that encodes position information representing the positions of point cloud data as an N-ary tree (N is an integer equal to or greater than 2) and encodes attribute information using the position information, and the second encoding method is a method (VPCC) that generates a two-dimensional image from the point cloud data and encodes the two-dimensional image using a video encoding method.

[0193] For example, the file conforms to ISOBMFF (ISO based media file format).

[0194] For example, the three-dimensional data storage device includes a processor and a memory, and the processor uses the memory to perform the above-mentioned processing.

[0195] As described above, the three-dimensional data acquisition device (or the three-dimensional data demultiplexing device, or the three-dimensional data decoding device) performs the process shown in FIG.

[0196] The three-dimensional data acquisition device (including, for example, the first demultiplexing unit 4720, the second demultiplexing unit 4740, or the third demultiplexing unit 4760) acquires a file (for example, an ISOBMFF file) that stores one or more units (for example, NAL units) in which an encoded stream in which point cloud data is encoded is stored (S4791). Next, the three-dimensional data acquisition device acquires one or more units from the file (S4792). In addition, the control information of the file (for example, ftyp) includes information (for example, pcc1, pcc2, or pcc3) that indicates that the data stored in the file is data in which point cloud data is encoded.

[0197] For example, the three-dimensional data acquisition device refers to the information and determines whether the data stored in the file is data obtained by encoding point cloud data. When the three-dimensional data acquisition device determines that the data stored in the file is data obtained by encoding point cloud data, the three-dimensional data acquisition device generates point cloud data by decoding the data obtained by encoding point cloud data included in one or more units. When the three-dimensional data acquisition device determines that the data stored in the file is data obtained by encoding point cloud data, the three-dimensional data acquisition device outputs (notifies) information indicating that the data included in one or more units is data obtained by encoding point cloud data to a downstream processing unit (for example, the first decoding unit 4640, the second decoding unit 4660, or the decoding unit 4680).

[0198] According to this, the three-dimensional data acquisition device can refer to the control information of the file and quickly determine whether the data stored in the file is encoded data of point cloud data or not, thereby reducing the amount of processing or speeding up the processing of the three-dimensional data acquisition device or a downstream device.

[0199] For example, the information further indicates the encoding method used for the encoding, either the first encoding method or the second encoding method. Note that the fact that the data stored in the file is data obtained by encoding point cloud data and the encoding method used for encoding the point cloud data, either the first encoding method or the second encoding method, may be indicated by a single piece of information or may be indicated by different pieces of information.

[0200] This allows the 3D data acquisition device to refer to the control information of the file and quickly determine the codec used for the data stored in the file, thereby reducing the amount of processing or speeding up the processing of the 3D data acquisition device or a downstream device.

[0201] For example, based on the information, the three-dimensional data acquisition device acquires data encoded by one of the encoding methods from encoded point cloud data which includes data encoded by a first encoding method and data encoded by a second encoding method.

[0202] For example, the first encoding method is a method (GPCC) that encodes position information representing the positions of point cloud data as an N-ary tree (N is an integer equal to or greater than 2) and encodes attribute information using the position information, and the second encoding method is a method (VPCC) that generates a two-dimensional image from the point cloud data and encodes the two-dimensional image using a video encoding method.

[0203] For example, the file conforms to ISOBMFF (ISO based media file format).

[0204] For example, the three-dimensional data acquisition device includes a processor and a memory, and the processor uses the memory to perform the above-mentioned processing.

[0205] (Embodiment 4) In this embodiment, the types of encoded data (position information (Geometry), attribute information (Attribute), additional information (Metadata)) generated by the above-mentioned first encoding unit 4630 or second encoding unit 4650, a generation method of the additional information (metadata), and multiplexing processing in the multiplexing unit will be described. Note that the additional information (metadata) may also be referred to as a parameter set or control information.

[0206] In this embodiment, the dynamic object (three-dimensional point cloud data that changes over time) described in Figure 4 will be used as an example, but a similar method may also be used in the case of a static object (three-dimensional point cloud data at any time).

[0207] 32 is a diagram showing configurations of an encoding unit 4801 and a multiplexing unit 4802 included in the three-dimensional data encoding device according to this embodiment. The encoding unit 4801 corresponds to, for example, the above-mentioned first encoding unit 4630 or the second encoding unit 4650. The multiplexing unit 4802 corresponds to the above-mentioned multiplexing unit 4634 or 4656.

[0208] The encoding unit 4801 encodes point cloud data of multiple PCC (Point Cloud Compression) frames, and generates encoded data (Multiple Compressed Data) of multiple pieces of position information, attribute information, and additional information.

[0209] The multiplexing unit 4802 converts data of multiple data types (position information, attribute information, and additional information) into NAL units, thereby converting the data into a data structure that takes into consideration data access in the decoding device.

[0210] 33 is a diagram showing an example of the structure of coded data generated by the coding unit 4801. The arrows in the diagram indicate dependencies related to the decoding of coded data, with the source of the arrow depending on the data at the tip of the arrow. In other words, the decoding device decodes the data at the tip of the arrow, and uses the decoded data to decode the data at the tip of the arrow. In other words, dependency means that the data at the destination of dependency is referenced (used) in the processing (encoding, decoding, etc.) of the data at the source of dependency.

[0211] First, the process of generating encoded data of position information will be described. The encoding unit 4801 generates encoded position data (compressed geometry data) for each frame by encoding the position information of each frame. The encoded position data is represented as G(i), where i indicates the frame number, the time of the frame, etc.

[0212] The encoding unit 4801 also generates a position parameter set (GPS(i)) corresponding to each frame. The position parameter set includes parameters that can be used to decode the encoded position data. The encoded position data for each frame depends on the corresponding position parameter set.

[0213] Moreover, encoded position data consisting of multiple frames is defined as a position sequence (Geometry Sequence). The encoding unit 4801 generates a position sequence parameter set (Geometry Sequence PS: also written as position SPS) that stores parameters commonly used in decoding processes for multiple frames in the position sequence. The position sequence depends on the position SPS.

[0214] Next, a process for generating encoded data of attribute information will be described. Encoding unit 4801 generates encoded attribute data (Compressed Attribute Data) for each frame by encoding the attribute information of each frame. The encoded attribute data is represented as A(i). Fig. 33 shows an example in which attribute X and attribute Y exist, and the encoded attribute data of attribute X is represented as AX(i) and the encoded attribute data of attribute Y is represented as AY(i).

[0215] The encoding unit 4801 also generates an attribute parameter set (APS(i)) corresponding to each frame. The attribute parameter set for attribute X is represented as AXPS(i), and the attribute parameter set for attribute Y is represented as AYPS(i). The attribute parameter set includes parameters that can be used to decode the encoded attribute information. The encoded attribute data depends on the corresponding attribute parameter set.

[0216] Moreover, encoded attribute data consisting of multiple frames is defined as an attribute sequence. The encoding unit 4801 generates an attribute sequence parameter set (Attribute Sequence PS: also referred to as attribute SPS) that stores parameters commonly used in decoding processes for multiple frames in the attribute sequence. The attribute sequence depends on the attribute SPS.

[0217] Furthermore, in the first encoding method, the encoded attribute data depends on the encoded position data.

[0218] Also, Fig. 33 shows an example in which two types of attribute information (attribute X and attribute Y) exist. When there are two types of attribute information, for example, two encoding units generate respective data and metadata. Also, for example, an attribute sequence is defined for each type of attribute information, and an attribute SPS is generated for each type of attribute information.

[0219] In addition, while FIG. 33 shows an example in which there is one type of position information and two types of attribute information, the present invention is not limited to this, and there may be one type of attribute information, or three or more types. In this case, encoded data can be generated in a similar manner. In addition, in the case of point cloud data that does not have attribute information, the attribute information may not be necessary. In this case, the encoding unit 4801 does not need to generate a parameter set related to the attribute information.

[0220] Next, a process of generating additional information (metadata) will be described. The encoding unit 4801 generates a PCC stream PS (also written as stream PS), which is a parameter set for the entire PCC stream. The encoding unit 4801 stores parameters that can be commonly used in decoding processes for one or more position sequences and one or more attribute sequences in the stream PS. For example, the stream PS includes identification information indicating the codec of the point cloud data, information indicating the algorithm used for encoding, and the like. The position sequence and the attribute sequence depend on the stream PS.

[0221] Next, an access unit and a GOF will be described. In this embodiment, the concept of an access unit (AU) and a group of frames (GOF) are newly introduced.

[0222] An access unit is a basic unit for accessing data during decoding, and is composed of one or more pieces of data and one or more pieces of metadata. For example, an access unit is composed of position information at the same time and one or more pieces of attribute information. A GOF is a random access unit, and is composed of one or more access units.

[0223] The encoding unit 4801 generates an access unit header (AU Header) as identification information indicating the beginning of an access unit. The encoding unit 4801 stores parameters related to the access unit in the access unit header. For example, the access unit header includes the configuration or information of the encoded data included in the access unit. The access unit header also includes parameters commonly used for data included in the access unit, such as parameters related to the decoding of the encoded data.

[0224] Alternatively, instead of an access unit header, the encoding unit 4801 may generate an access unit delimiter that does not include parameters related to the access unit. This access unit delimiter is used as identification information indicating the beginning of the access unit. The decoding device identifies the beginning of the access unit by detecting the access unit header or the access unit delimiter.

[0225] Next, generation of identification information for the start of a GOF will be described. The encoding unit 4801 generates a GOF header as identification information indicating the start of a GOF. The encoding unit 4801 stores parameters related to the GOF in the GOF header. For example, the GOF header includes the configuration or information of the encoded data included in the GOF. The GOF header also includes parameters commonly used for data included in the GOF, such as parameters related to the decoding of the encoded data.

[0226] Instead of a GOF header, the encoding unit 4801 may generate a GOF delimiter that does not include parameters related to the GOF. This GOF delimiter is used as identification information indicating the beginning of the GOF. The decoding device identifies the beginning of the GOF by detecting the GOF header or the GOF delimiter.

[0227] In PCC encoded data, for example, an access unit is defined as a PCC frame unit, and a decoding device accesses a PCC frame based on identification information at the beginning of the access unit.

[0228] Also, for example, GOF is defined as one random access unit. The decoding device accesses the random access unit based on the identification information at the beginning of the GOF. For example, if PCC frames are not dependent on each other and can be decoded independently, the PCC frames may be defined as the random access unit.

[0229] Note that two or more PCC frames may be assigned to one access unit, and multiple random access units may be assigned to one GOF.

[0230] Furthermore, the encoding unit 4801 may define and generate parameter sets or metadata other than those described above. For example, the encoding unit 4801 may generate SEI (Supplemental Enhancement Information) that stores parameters (optional parameters) that may not necessarily be used during decoding.

[0231] Next, the structure of the coded data and the method of storing the coded data in the NAL unit will be described.

[0232] For example, a data format is defined for each type of encoded data. Figure 34 shows an example of encoded data and NAL units.

[0233] For example, as shown in Fig. 34, the encoded data includes a header and a payload. The encoded data may include length information indicating the length (amount of data) of the encoded data, the header, or the payload. The encoded data may not include a header.

[0234] The header includes, for example, identification information for identifying the data, which indicates, for example, the data type or the frame number.

[0235] The header includes, for example, identification information indicating a reference relationship. This identification information is stored in the header when, for example, there is a dependency between data, and is information for referring to the reference destination from the reference source. For example, the header of the reference destination includes identification information for identifying the data. The header of the reference source includes identification information indicating the reference destination.

[0236] In addition, when the reference destination or the reference source can be identified or derived from other information, the identification information for specifying the data or the identification information indicating the reference relationship may be omitted.

[0237] The multiplexing unit 4802 stores the encoded data in the payload of the NAL unit. The NAL unit header includes pcc_nal_unit_type, which is identification information of the encoded data. Figure 35 shows an example of the semantics of pcc_nal_unit_type.

[0238] 35, when pcc_codec_type is codec 1 (Codec1: first encoding method), values ​​0 to 10 of pcc_nal_unit_type are assigned to the encoded position data (Geometry), encoded attribute X data (AttributeX), encoded attribute Y data (AttributeY), position PS (Geom.PS), attribute XPS (AttrX.PS), attribute YPS (AttrX.PS), position SPS (Geometry Sequence PS), attribute XSPS (AttributeX Sequence PS), attribute YSPS (AttributeY Sequence PS), AU header (AU Header), and GOF header (GOF Header) in codec 1. Values ​​11 and above are assigned as spares for codec 1.

[0239] When pcc_codec_type is Codec2 (Codec2: second encoding method), values ​​0 to 2 of pcc_nal_unit_type are assigned to codec data A (DataA), metadata A (MetaDataA), and metadata B (MetaDataB). Values ​​3 and above are assigned as spares for Codec2.

[0240] Next, the data transmission order will be described. The following describes the constraints on the transmission order of NAL units.

[0241] The multiplexing unit 4802 collectively transmits NAL units in units of GOF or AU. The multiplexing unit 4802 places a GOF header at the beginning of a GOF, and places an AU header at the beginning of an AU.

[0242] The multiplexing unit 4802 may allocate a sequence parameter set (SPS) for each AU so that the decoding device can decode from the next AU even if data is lost due to packet loss or the like.

[0243] If there is a dependency relationship related to decoding in the encoded data, the decoding device decodes the reference data after decoding the reference data. In order to enable the decoding device to decode the data in the order in which it was received without rearranging the data, the multiplexing unit 4802 sends out the reference data first.

[0244] Fig. 36 is a diagram showing examples of the transmission order of NAL units, showing three examples: position information priority, parameter priority, and data integration.

[0245] The position information priority transmission order is an example in which information related to position information and information related to attribute information are transmitted together. In this transmission order, the transmission of information related to position information is completed earlier than the transmission of information related to attribute information.

[0246] For example, by using this transmission order, a decoding device that does not decode attribute information may be able to set a time during which it does not process the attribute information by ignoring the decoding of the attribute information. Also, for example, in the case of a decoding device that wishes to decode position information quickly, it may be able to decode the position information more quickly by obtaining the encoded data of the position information quickly.

[0247] In FIG. 36, the attributes XSPS and YSPS are integrated and written as the attribute SPS, but the attributes XSPS and YSPS may be arranged separately.

[0248] In a parameter set priority sending order, the parameter sets are sent first and the data is sent later.

[0249] As described above, as long as the constraints on the NAL unit transmission order are met, the multiplexing unit 4802 may transmit the NAL units in any order. For example, order identification information may be defined, and the multiplexing unit 4802 may have a function for transmitting the NAL units in a number of different orders. For example, the NAL unit order identification information may be stored in the stream PS.

[0250] The three-dimensional data decoding device may perform decoding based on the order identification information. The three-dimensional data decoding device may instruct the three-dimensional data encoding device of a desired transmission order, and the three-dimensional data encoding device (multiplexing unit 4802) may control the transmission order according to the instructed transmission order.

[0251] The multiplexing unit 4802 may generate coded data in which multiple functions are merged, as long as the data is transmitted in a certain order, such as in the transmission order of the integrated data. For example, as shown in FIG. 36, the GOF header and the AU header may be integrated, or the AXPS and the AYPS may be integrated. In this case, an identifier indicating that the data has multiple functions is defined in the pcc_nal_unit_type.

[0252] A modified example of this embodiment will be described below. If the PS has levels, such as a frame-level PS, a sequence-level PS, and a PCC sequence-level PS, and the PCC sequence level is the higher level and the frame level is the lower level, the following method may be used to store parameters.

[0253] The default PS value is indicated in the higher PS. Also, if the value of the lower PS differs from the value of the higher PS, the PS value is indicated in the lower PS. Or, the PS value is not written in the higher PS, and is written in the lower PS. Or, information on whether the PS value is to be written in the lower PS, the higher PS, or both is indicated in either or both of the lower PS and the higher PS. Or, the lower PS may be merged into the higher PS. Or, if the lower PS and the higher PS overlap, the multiplexing unit 4802 may omit sending one of them.

[0254] The encoding unit 4801 or the multiplexing unit 4802 may divide data into slices or tiles, and transmit the divided data. The divided data includes information for identifying the divided data, and parameters used for decoding the divided data are included in the parameter set. In this case, an identifier indicating that the data stores data or parameters related to tiles or slices is defined in pcc_nal_unit_type.

[0255] (Embodiment 5) A method for dividing point cloud data will be described below. Fig. 37 is a diagram showing an example of division into slices and tiles.

[0256] First, a method of dividing into slices will be described. The three-dimensional data encoding device divides the three-dimensional point group data into arbitrary point groups in slice units. In the slice division, the three-dimensional data encoding device does not divide the position information and attribute information constituting a point, but divides the position information and attribute information together. That is, the three-dimensional data encoding device divides into slices so that the position information and attribute information at an arbitrary point belong to the same slice. In addition, according to these, the number of divisions and the division method may be any method. In addition, the minimum unit of division is a point. For example, the number of divisions of the position information and the attribute information are the same. For example, the three-dimensional point corresponding to the position information after the slice division and the three-dimensional point corresponding to the attribute information are included in the same slice.

[0257] Furthermore, the 3D data encoding device generates slice additional information, which is additional information related to the number of divisions and the division method when dividing a slice. The slice additional information is the same as the position information and the attribute information. For example, the slice additional information includes information indicating the reference coordinate position, size, or side length of the bounding box after division. Furthermore, the slice additional information includes information indicating the number of divisions, the division type, etc.

[0258] Next, a tile division method will be described. The three-dimensional data encoding device divides the sliced ​​data into slice position information (G slices) and slice attribute information (A slices), and divides each of the slice position information and slice attribute information into tiles.

[0259] Although FIG. 37 shows an example of division using an octree structure, the number of divisions and the division method may be any method.

[0260] Furthermore, the three-dimensional data encoding device may divide the position information and the attribute information using different division methods or the same division method. Furthermore, the three-dimensional data encoding device may divide a plurality of slices into tiles using different division methods or the same division method.

[0261] Furthermore, the 3D data encoding device generates tile additional information related to the number of divisions and the division method when dividing tiles. The tile additional information (position tile additional information and attribute tile additional information) is independent of position information and attribute information. For example, the tile additional information includes information indicating the reference coordinate position, size, or side length of the bounding box after division. The tile additional information also includes information indicating the number of divisions, the division type, etc.

[0262] Next, an example of a method for dividing the point cloud data into slices or tiles will be described. The three-dimensional data encoding device may use a predetermined method as a method for dividing the point cloud data into slices or tiles, or may adaptively switch the method to be used depending on the point cloud data.

[0263] When dividing into slices, the three-dimensional data encoding device divides the three-dimensional space collectively based on the position information and the attribute information. For example, the three-dimensional data encoding device determines the shape of an object and divides the three-dimensional space into slices according to the shape of the object. For example, the three-dimensional data encoding device extracts objects such as trees or buildings, and divides the space on an object-by-object basis. For example, the three-dimensional data encoding device divides the space into slices so that one or more objects are entirely included in one slice. Alternatively, the three-dimensional data encoding device divides one object into multiple slices.

[0264] In this case, the encoding device may change the encoding method for each slice, for example. For example, the encoding device may use a high-quality compression method for a specific object or a specific part of an object. In this case, the encoding device may store information indicating the encoding method for each slice in additional information (metadata).

[0265] Furthermore, the three-dimensional data encoding device may divide the image into slices based on map information or position information so that each slice corresponds to a predetermined coordinate space.

[0266] When dividing into tiles, the three-dimensional data encoding device divides the position information and the attribute information independently. For example, the three-dimensional data encoding device divides a slice into tiles according to the amount of data or the amount of processing. For example, the three-dimensional data encoding device determines whether the amount of data of a slice (e.g., the number of three-dimensional points included in a slice) is greater than a predetermined threshold. If the amount of data of a slice is greater than the threshold, the three-dimensional data encoding device divides the slice into tiles. If the amount of data of a slice is less than the threshold, the three-dimensional data encoding device does not divide the slice into tiles.

[0267] For example, a three-dimensional data encoding device divides slices into tiles so that the amount of processing or the processing time in a decoding device is within a certain range (a predetermined value or less). This makes the amount of processing per tile in the decoding device constant, facilitating distributed processing in the decoding device.

[0268] In addition, when the processing amount differs between the position information and the attribute information, for example, when the processing amount of the position information is greater than the processing amount of the attribute information, the three-dimensional data encoding device makes the number of divisions of the position information greater than the number of divisions of the attribute information.

[0269] Also, for example, in the case where the decoding device may decode and display the position information quickly and the attribute information may be decoded and displayed slowly later depending on the content, the three-dimensional data encoding device may divide the position information into a number greater than the number of divisions of the attribute information. This allows the decoding device to process a larger number of pieces of position information in parallel, thereby making it possible to process the position information faster than the attribute information.

[0270] Note that the decoding device does not necessarily need to process sliced ​​or tiled data in parallel, and may determine whether to process the data in parallel depending on the number or capabilities of the decoding processing units.

[0271] By dividing the image in the above manner, it is possible to realize adaptive encoding according to the content or object. In addition, it is possible to realize parallel processing in the decoding process. This improves the flexibility of the point cloud encoding system or the point cloud decoding system.

[0272] Fig. 38 is a diagram showing an example of a division pattern of slices and tiles. DU in the diagram is a data unit (DataUnit) and indicates data of a tile or slice. Each DU includes a slice index (SliceIndex) and a tile index (TileIndex). The numerical value in the upper right of the DU in the diagram indicates the slice index, and the numerical value in the lower left of the DU indicates the tile index.

[0273] In pattern 1, the number of divisions and the division method are the same for G slices and A slices in slice division. In tile division, the number of divisions and the division method for G slices are different from the number of divisions and the division method for A slices. Furthermore, the same number of divisions and the division method are used among multiple G slices. The same number of divisions and the division method are used among multiple A slices.

[0274] In pattern 2, the number of divisions and the division method are the same for G slices and A slices in slice division. In tile division, the number of divisions and the division method for G slices are different from the number of divisions and the division method for A slices. In addition, the number of divisions and the division method are different between multiple G slices. The number of divisions and the division method are different between multiple A slices.

[0275] (Embodiment 6) An example of dividing the data into tiles and then dividing the data into slices will be described below. In an autonomous application such as an automatic driving vehicle, point cloud data of the area around the vehicle or the area in the direction of travel of the vehicle is required, rather than point cloud data of the entire area. Here, tiles and slices can be used to selectively decode the original point cloud data. By dividing the three-dimensional point cloud data into tiles and further dividing the slices, it is possible to improve the coding efficiency or realize parallel processing. When dividing the data, additional information (metadata) is generated, and the generated additional information is sent to a multiplexing unit.

[0276] 39 is a block diagram showing a configuration of a first encoding unit 5010 included in the three-dimensional data encoding device according to this embodiment. The first encoding unit 5010 generates encoded data (encoded stream) by encoding point cloud data using a first encoding method (GPCC (Geometry based PCC)). The first encoding unit 5010 includes a division unit 5011, a plurality of position information encoding units 5012, a plurality of attribute information encoding units 5013, an additional information encoding unit 5014, and a multiplexing unit 5015.

[0277] The dividing unit 5011 divides the point cloud data to generate a plurality of divided data. Specifically, the dividing unit 5011 divides the space of the point cloud data into a plurality of subspaces to generate a plurality of divided data. Here, the subspace is one of a tile and a slice, or a combination of a tile and a slice. More specifically, the point cloud data includes position information, attribute information, and additional information. The dividing unit 5011 divides the position information into a plurality of divided position information, and divides the attribute information into a plurality of divided attribute information. In addition, the dividing unit 5011 generates additional information related to the division.

[0278] For example, the dividing unit 5011 first divides the point cloud into tiles, and then further divides the obtained tiles into slices.

[0279] The position information encoding units 5012 generate a plurality of pieces of encoded position information by encoding the plurality of pieces of divided position information. For example, the position information encoding units 5012 process the plurality of pieces of divided position information in parallel.

[0280] The attribute information encoding units 5013 generate a plurality of pieces of encoded attribute information by encoding the plurality of pieces of divided attribute information. For example, the attribute information encoding units 5013 process the plurality of pieces of divided attribute information in parallel.

[0281] The additional information encoding unit 5014 generates encoded additional information by encoding the additional information included in the point cloud data and the additional information related to the data division generated by the division unit 5011 at the time of division.

[0282] The multiplexing unit 5015 multiplexes a plurality of pieces of encoding position information, a plurality of pieces of encoding attribute information, and encoding additional information to generate encoded data (encoded stream), and transmits the generated encoded data. In addition, the encoded additional information is used during decoding.

[0283] 39 shows an example in which there are two position information encoders 5012 and two attribute information encoders 5013, but the number of position information encoders 5012 and two attribute information encoders 5013 may be one each, or three or more. Furthermore, multiple pieces of divided data may be processed in parallel within the same chip, such as multiple cores in a CPU, or may be processed in parallel by cores on multiple chips, or may be processed in parallel by multiple cores on multiple chips.

[0284] Next, the decoding process will be described. Fig. 40 is a block diagram showing the configuration of the first decoding unit 5020. The first decoding unit 5020 restores the point cloud data by decoding the encoded data (encoded stream) generated by encoding the point cloud data by the first encoding method (GPCC). The first decoding unit 5020 includes a demultiplexing unit 5021, a plurality of position information decoding units 5022, a plurality of attribute information decoding units 5023, an additional information decoding unit 5024, and a combining unit 5025.

[0285] The demultiplexer 5021 demultiplexes the coded data (coded stream) to generate a plurality of pieces of coding position information, a plurality of pieces of coding attribute information, and coded additional information.

[0286] The position information decoding units 5022 generate a plurality of pieces of divided position information by decoding the plurality of pieces of encoded position information. For example, the position information decoding units 5022 process the plurality of pieces of encoded position information in parallel.

[0287] The multiple attribute information decoding units 5023 generate multiple pieces of divided attribute information by decoding the multiple pieces of encoded attribute information. For example, the multiple attribute information decoding units 5023 process the multiple pieces of encoded attribute information in parallel.

[0288] The multiple additional information decoders 5024 generate additional information by decoding the encoded additional information.

[0289] The combining unit 5025 generates position information by combining a plurality of pieces of divided position information using the additional information. The combining unit 5025 generates attribute information by combining a plurality of pieces of divided attribute information using the additional information. For example, the combining unit 5025 first generates point cloud data corresponding to a tile by combining decoded point cloud data for a slice using the slice additional information. Next, the combining unit 5025 restores the original point cloud data by combining the point cloud data corresponding to the tile using the tile additional information.

[0290] 39 shows an example in which the number of each of the position information decoding units 5022 and the attribute information decoding units 5023 is two, but the number of each of the position information decoding units 5022 and the attribute information decoding units 5023 may be one, or three or more. Furthermore, the multiple pieces of divided data may be processed in parallel within the same chip, such as multiple cores within a CPU, or may be processed in parallel by cores on multiple chips, or may be processed in parallel by multiple cores on multiple chips.

[0291] Next, a method for dividing point cloud data will be described. In an autonomous application such as an automatic driving of a vehicle, point cloud data of an area around a vehicle or an area in a traveling direction of the vehicle is required, instead of point cloud data of an entire area.

[0292] Fig. 41 is a diagram showing examples of tile shapes. As shown in Fig. 41, various shapes such as a circle, a rectangle, or an ellipse may be used as the tile shape.

[0293] FIG. 42 is a diagram showing an example of tiles and slices. The configuration of slices may differ between tiles. For example, the configuration of tiles or slices may be optimized based on the amount of data. Or, the configuration of tiles or slices may be optimized based on the decoding speed.

[0294] Alternatively, tile division may be performed based on position information, in which case attribute information is divided in the same manner as the corresponding position information.

[0295] In addition, after dividing into tiles, the image may be divided into slices using a method different from that used for the position information and the attribute information. For example, the method for dividing into slices in each tile may be selected according to a request from an application. A different method for dividing into slices or a method for dividing into tiles may be used based on the request from the application.

[0296] For example, the dividing unit 5011 divides the three-dimensional point cloud data into one or more tiles based on position information such as map information in a two-dimensional shape viewed from above. Then, the dividing unit 5011 divides each tile into one or more slices.

[0297] The dividing unit 5011 may divide the position information (Geometry) and the attribute information (Attribute) into slices in the same manner.

[0298] The position information and the attribute information may each be of one type or of two or more types. In addition, in the case of point cloud data that does not have attribute information, the attribute information may not be included.

[0299] 43 is a block diagram of the dividing unit 5011. The dividing unit 5011 includes a tile dividing unit 5031, a geometry slice dividing unit 5032, and an attribute slice dividing unit 5033.

[0300] The tile division unit 5031 generates a plurality of pieces of tile position information by dividing position information (Position (Geometry)) into tiles. The tile division unit 5031 also generates a plurality of pieces of tile attribute information by dividing attribute information (Attribute) into tiles. The tile division unit 5031 also outputs tile additional information (TileMetaData) including information related to the tile division and information generated in the tile division.

[0301] The position information slice division unit 5032 divides a plurality of pieces of tile position information into slices to generate a plurality of pieces of divided position information (a plurality of pieces of slice position information). In addition, the position information slice division unit 5032 outputs position slice additional information (Geometry Slice MetaData) including information related to the division of the position information into slices and information generated in the division of the position information into slices.

[0302] The attribute information slice division unit 5033 divides a plurality of pieces of tile attribute information into slices to generate a plurality of pieces of divided attribute information (a plurality of pieces of slice attribute information). In addition, the attribute information slice division unit 5033 outputs attribute slice additional information (Attribute Slice MetaData) including information related to the division of the attribute information into slices and information generated in the division of the attribute information into slices.

[0303] Next, examples of tile shapes will be described. The entire three-dimensional map (3D map) is divided into a plurality of tiles. Data of the plurality of tiles is selectively transmitted to the three-dimensional data decoding device. Alternatively, data of the plurality of tiles is transmitted to the three-dimensional data decoding device in descending order of importance. The shape of the tile may be selected from a plurality of shapes depending on the situation.

[0304] Fig. 44 is a diagram showing an example of a map in which point cloud data obtained by LiDAR is viewed from above. The example shown in Fig. 44 is point cloud data of a highway, and includes a multi-level intersection (flyover).

[0305] FIG. 45 is a diagram showing an example in which the point cloud data shown in FIG. 44 is divided into square tiles. Such division into squares can be easily performed by the map server. Furthermore, the height of the tiles is set low for normal roads. At intersections, the height of the tiles is set higher than that of normal roads so that the tiles include the intersections.

[0306] Fig. 46 is a diagram showing an example in which the point cloud data shown in Fig. 44 is divided into circular tiles. In this case, adjacent tiles may overlap in a plan view. When the vehicle requires point cloud data of the surrounding area, the three-dimensional data encoding device transmits point cloud data of a cylindrical area (a circle in a top view) around the vehicle to the vehicle.

[0307] Also, the height of the tiles is set low for normal roads, as in the example of Figure 45. At intersections, the height of the tiles is set higher than for normal roads so that the tiles encompass the intersections.

[0308] The three-dimensional data encoding device may change the height of a tile according to, for example, the shape or height of a road or a building. The three-dimensional data encoding device may also change the height of a tile according to position information or area information. The three-dimensional data encoding device may also change the height of a tile for each tile. Or, the three-dimensional data encoding device may change the height of a tile for each section that includes multiple tiles. In other words, the three-dimensional data encoding device may make the heights of multiple tiles within a section the same. Also, tiles of different heights may overlap when viewed from above.

[0309] 47 is a diagram showing an example of tile division when tiles of various shapes, sizes, or heights are used. The shape of the tiles may be any shape, any size, or a combination of these.

[0310] For example, in addition to the above-mentioned examples of dividing into square tiles without overlapping and into overlapping circular tiles, the three-dimensional data encoding device may divide into overlapping square tiles. Also, the shape of the tiles does not have to be square or circular, and a polygon with three or more vertices or a shape with no vertices may be used.

[0311] In addition, the tile shapes may be of two or more types, or tiles of different shapes may overlap. In addition, the tile shapes may be of one or more types, and shapes of different sizes may be combined in the same shape to be divided, or they may overlap.

[0312] For example, tiles larger than those used for areas where objects such as roads do not exist are used. Furthermore, the three-dimensional data encoding device may adaptively change the shape or size of tiles depending on the object.

[0313] Also, for example, since it is highly likely that the three-dimensional data encoding device will need to read tiles far in front of the automobile, which is the direction of travel of the automobile (vehicle), the tiles in the direction of travel may be set to a larger size, and since it is unlikely that the automobile will travel to the side of the automobile, the tiles to the side may be set to a smaller size than the tiles in the direction of travel.

[0314] FIG. 48 is a diagram showing an example of tile data stored in a server. For example, point cloud data is divided into tiles in advance and encoded, and the resulting encoded data is stored in the server. A user obtains data of a desired tile from the server when necessary. Alternatively, the server (three-dimensional data encoding device) may perform tile division and encoding in response to an instruction from the user so as to include data desired by the user.

[0315] For example, when the moving body (vehicle) moves at a high speed, it is considered that point cloud data covering a wider range is required. Therefore, the server may determine the shape and size of the tile based on the vehicle speed estimated in advance (for example, the legal speed limit of the road, the vehicle speed estimated from the width and shape of the road, or a statistical speed, etc.) and perform tile division. Alternatively, as shown in FIG. 48, the server may encode tiles of a plurality of shapes or sizes in advance and store the obtained data. The moving body may obtain tile data of an appropriate shape and size according to the moving direction and speed of the moving body.

[0316] Fig. 49 is a diagram showing an example of a system related to tile division. As shown in Fig. 49, the shape and area of ​​the tile may be determined based on the position of an antenna (base station) which is a communication means for transmitting point cloud data, or the communication area supported by the antenna. Alternatively, when the point cloud data is generated by a sensor such as a camera, the shape and area of ​​the tile may be determined based on the position of the sensor or the target range (detection range) of the sensor.

[0317] One tile may be assigned to one antenna or sensor, or one tile may be assigned to multiple antennas or sensors. Multiple tiles may be assigned to one antenna or sensor. The antennas or sensors may be fixed or movable.

[0318] For example, the coded data divided into tiles may be managed by a server connected to an antenna or a sensor for an area assigned to the tile. The server may manage the coded data for its own area and tile information for adjacent areas. A centralized management server (cloud) that manages a plurality of servers corresponding to each tile may manage a plurality of coded data for a plurality of tiles. Alternatively, a server corresponding to each tile may not be provided, and an antenna or a sensor may be directly connected to the centralized management server.

[0319] The target range of an antenna or a sensor may vary depending on the power of radio waves, differences in equipment, and installation conditions, and the shape and size of the tiles may also vary accordingly. Based on the target range of an antenna or a sensor, slices, rather than tiles, may be assigned, or PCC frames may be assigned.

[0320] Next, we explain how to divide tiles into slices, which can improve coding efficiency by assigning similar objects to the same slice.

[0321] For example, the three-dimensional data encoding device may recognize objects (roads, buildings, trees, etc.) using the features of the point cloud data, and divide the point cloud into slices by clustering the point cloud for each object.

[0322] Alternatively, the three-dimensional data encoding device may perform slice division by grouping objects having the same attribute and allocating slices to each group. Here, the attribute is, for example, information related to movement, and grouping is performed by classifying objects into dynamic information such as pedestrians and cars, semi-dynamic information such as accidents and congestion, semi-static information such as traffic regulations and road construction, and static information such as road surfaces and structures.

[0323] Note that data may overlap between multiple slices. For example, when dividing slices into multiple object groups, any object may belong to one object group, or may belong to two or more object groups.

[0324] Fig. 50 is a diagram showing an example of this slice division. For example, in the example shown in Fig. 50, the tiles are rectangular parallelepipeds. Note that the tiles may be cylindrical or may have other shapes.

[0325] The points in a tile are grouped into object groups, e.g., roads, buildings, trees, etc. Then, the slicing is performed such that each object group is contained in one slice, and each slice is then coded separately.

[0326] Next, a method for encoding divided data will be described. A three-dimensional data encoding device (first encoding unit 5010) encodes each of the divided data. When encoding attribute information, the three-dimensional data encoding device generates dependency information indicating which configuration information (position information, additional information, or other attribute information) was used for encoding as additional information. That is, the dependency information indicates, for example, the configuration information of the reference destination (dependency destination). In this case, the three-dimensional data encoding device generates dependency information based on configuration information corresponding to the division shape of the attribute information. The three-dimensional data encoding device may generate dependency information based on configuration information corresponding to a plurality of division shapes.

[0327] The dependency information may be generated by the three-dimensional data encoding device, and the generated dependency information may be sent to the three-dimensional data decoding device. Alternatively, the three-dimensional data decoding device may generate the dependency information, and the three-dimensional data encoding device may not send the dependency information. Also, the dependency relationships used by the three-dimensional data encoding device may be determined in advance, and the three-dimensional data encoding device may not send the dependency information.

[0328] Figure 51 is a diagram showing an example of the dependency relationship of each data. The tip of the arrow in the figure indicates the dependency destination, and the start of the arrow indicates the dependency source. The three-dimensional data decoding device decodes data in the order from the dependency destination to the dependency source. Also, data shown by solid lines in the figure is data that is actually sent, and data shown by dotted lines is data that is not sent.

[0329] In the figure, G indicates location information, and A indicates attribute information. t1 indicates the position information of tile number 1, and G t2 indicates the position information of tile number 2. t1s1 indicates the position information of tile number 1 and slice number 1, and G t1s2 indicates the position information of tile number 1 and slice number 2, and G t2s1 indicates the position information of tile number 2 and slice number 1, and G t2s2 indicates the position information of tile number 2 and slice number 2. Similarly, A t1 indicates the attribute information of tile number 1, and A t2 indicates the attribute information of tile number 2. t1s1 indicates the attribute information of tile number 1 and slice number 1, and A t1s2 indicates the attribute information of tile number 1 and slice number 2, and A t2s1 indicates the attribute information of tile number 2 and slice number 1, and A t2s2 indicates attribute information of tile number 2 and slice number 2.

[0330] Mtile indicates tile additional information, MGslice indicates position slice additional information, and MAslice indicates attribute slice additional information. t1s1 is attribute information At1s1 D t2s1 is attribute information A t2s1 This shows dependency information for

[0331] It should be noted that different tile or slice division structures may be used depending on the application, etc.

[0332] Furthermore, the three-dimensional data encoding device may rearrange the data in the decoding order so that there is no need to rearrange the data in the three-dimensional data decoding device. Note that the data may be rearranged in the three-dimensional data decoding device, or the data may be rearranged in both the three-dimensional data encoding device and the three-dimensional data decoding device.

[0333] Fig. 52 is a diagram showing an example of the data decoding order. In the example of Fig. 52, decoding is performed in order from the left data. When data has a dependency relationship, the three-dimensional data decoding device decodes the dependent data first. For example, the three-dimensional data encoding device rearranges the data in advance so as to achieve this order, and transmits the data. Any order may be used as long as the dependent data comes first. The three-dimensional data encoding device may also transmit additional information and dependency information before the data.

[0334] Also, the three-dimensional data decoding device may selectively decode tiles based on a request from an application and information obtained from the NAL unit header. Figure 53 is a diagram showing an example of encoded data of tiles. For example, the order of decoding tiles is arbitrary. In other words, there may be no dependency between tiles.

[0335] Next, a description will be given of the configuration of the combining unit 5025 included in the first decoding unit 5020. Fig. 54 is a block diagram showing the configuration of the combining unit 5025. The combining unit 5025 includes a position information slice combining unit 5041 (geometry slice combiner), an attribute information slice combining unit 5042 (attribute slice combiner), and a tile combining unit (tile combiner).

[0336] The position information slice combining unit 5041 generates a plurality of pieces of tile position information by combining a plurality of pieces of divided position information using the position slice additional information. The attribute information slice combining unit 5042 generates a plurality of pieces of tile attribute information by combining a plurality of pieces of divided attribute information using the attribute slice additional information.

[0337] The tile combining unit 5043 generates position information by combining multiple pieces of tile position information using the tile additional information. Also, the tile combining unit 5043 generates attribute information by combining multiple pieces of tile attribute information using the tile additional information.

[0338] The number of slices or tiles to be divided is equal to or greater than 1. In other words, the division into slices or tiles does not necessarily have to be performed.

[0339] Next, a structure of coded data divided into slices or tiles and a method of storing the coded data in NAL units (multiplexing method) will be described. Figure 55 is a diagram showing a structure of coded data and a method of storing the coded data in NAL units.

[0340] The encoded data (partition position information and partition attribute information) is stored in the payload of the NAL unit.

[0341] The encoded data includes a header and a payload. The header includes identification information for identifying data included in the payload. This identification information includes, for example, a type of slice division or tile division (slice_type, tile_type), index information for identifying a slice or tile (slice_idx, tile_idx), position information of data (slice or tile), or an address of data (address). The index information for identifying a slice is also referred to as a slice index (SliceIndex). The index information for identifying a tile is also referred to as a tile index (TileIndex). The type of division is, for example, a method based on an object shape as described above, a method based on map information or position information, or a method based on a data amount or a processing amount.

[0342] Furthermore, the header of the encoded data includes identification information indicating a dependency relationship. That is, when there is a dependency relationship between data, the header includes identification information for referring to the dependency from the dependency source. For example, the header of the dependency destination data includes identification information for identifying the data. The header of the dependency source data includes identification information indicating the dependency. Note that, when the identification information for identifying the data, the additional information related to the slice division or tile division, and the identification information indicating the dependency relationship can be identified or derived from other information, these pieces of information may be omitted.

[0343] Next, a flow of encoding and decoding processing of point cloud data according to this embodiment will be described. Fig. 56 is a flowchart of encoding processing of point cloud data according to this embodiment.

[0344] First, the three-dimensional data encoding device determines a division method to be used (S5011). The division method includes whether or not to perform tile division and whether or not to perform slice division. The division method may also include the number of divisions when performing tile division or slice division, and the type of division. The type of division may be a method based on the object shape as described above, a method based on map information or position information, or a method based on the amount of data or the amount of processing. The division method may be determined in advance.

[0345] If tile division is performed (Yes in S5012), the three-dimensional data encoding device generates multiple pieces of tile position information and multiple pieces of tile attribute information by dividing the position information and attribute information together (S5013). The three-dimensional data encoding device also generates tile additional information related to the tile division. Note that the three-dimensional data encoding device may divide the position information and the attribute information independently.

[0346] When slice division is performed (Yes in S5014), the three-dimensional data encoding device generates a plurality of division position information and a plurality of division attribute information by independently dividing a plurality of pieces of tile position information and a plurality of pieces of tile attribute information (or position information and attribute information) (S5015). In addition, the three-dimensional data encoding device generates position slice additional information and attribute slice additional information related to the slice division. Note that the three-dimensional data encoding device may divide the tile position information and the tile attribute information together.

[0347] Next, the three-dimensional data encoding device generates a plurality of pieces of encoding position information and a plurality of pieces of encoding attribute information by encoding each of the plurality of pieces of division position information and the plurality of pieces of division attribute information (S5016). Also, the three-dimensional data encoding device generates dependency relationship information.

[0348] Next, the three-dimensional data encoding device generates encoded data (encoded stream) by forming (multiplexing) the plurality of pieces of encoding position information, the plurality of pieces of encoding attribute information, and the additional information into NAL units (S5017). In addition, the three-dimensional data encoding device transmits the generated encoded data.

[0349] 57 is a flowchart of a decoding process of point cloud data according to this embodiment. First, the three-dimensional data decoding device determines the division method by analyzing additional information (tile additional information, position slice additional information, and attribute slice additional information) related to the division method included in the encoded data (encoded stream) (S5021). This division method includes whether or not to perform tile division and whether or not to perform slice division. In addition, the division method may include the number of divisions when performing tile division or slice division, the type of division, and the like.

[0350] Next, the three-dimensional data decoding device generates split position information and split attribute information by decoding the multiple pieces of encoded position information and multiple pieces of encoded attribute information contained in the encoded data using dependency information contained in the encoded data (S5022).

[0351] When the additional information indicates that slice division has been performed (Yes in S5023), the three-dimensional data decoding device generates a plurality of tile position information and a plurality of tile attribute information by combining the plurality of pieces of division position information and the plurality of pieces of division attribute information by respective methods based on the position slice additional information and the attribute slice additional information (S5024). Note that the three-dimensional data decoding device may combine the plurality of pieces of division position information and the plurality of pieces of division attribute information by the same method.

[0352] If the additional information indicates that tile division has been performed (Yes in S5025), the three-dimensional data decoding device generates position information and attribute information by combining multiple pieces of tile position information and multiple pieces of tile attribute information (multiple pieces of division position information and multiple pieces of division attribute information) in the same manner based on the tile additional information (S5026). Note that the three-dimensional data decoding device may combine multiple pieces of tile position information and multiple pieces of tile attribute information in different manners.

[0353] Next, the tile additional information will be described. The three-dimensional data encoding device generates tile additional information, which is metadata related to a method of dividing tiles, and transmits the generated tile additional information to the three-dimensional data decoding device.

[0354] Fig. 58 is a diagram showing an example of the syntax of tile additional information (TileMetaData). As shown in Fig. 58, for example, the tile additional information includes division method information (type_of_divide), shape information (topview_shape), overlap flag (tile_overlap_flag), overlap information (type_of_overlap), height information (tile_height), number of tiles (tile_number), and tile position information (global_position, relative_position).

[0355] The division method information (type_of_divide) indicates a division method of tiles. For example, the division method information indicates whether the division method of tiles is based on map information, that is, division based on a top view (top_view), or other (other).

[0356] The shape information (topview_shape) is included in the tile additional information, for example, when the tile division method is division based on a top view. The shape information indicates the shape of the tile when viewed from above. For example, this shape includes a square and a circle. Note that this shape may include an ellipse, a rectangle, or a polygon other than a quadrangle, or may include other shapes. Note that the shape information is not limited to the shape of the tile when viewed from above, and may also indicate the three-dimensional shape of the tile (for example, a cube, a cylinder, etc.).

[0357] The overlap flag (tile_overlap_flag) indicates whether tiles overlap. For example, the overlap flag is included in the tile additional information when the tile division method is division based on a top view. In this case, the overlap flag indicates whether tiles overlap in a top view. Note that the overlap flag may also indicate whether tiles overlap in a three-dimensional space.

[0358] The overlap information (type_of_overlap) is included in the tile additional information when tiles overlap, for example. The overlap information indicates how the tiles overlap, etc. For example, the overlap information indicates the size of the overlapping area, etc.

[0359] Height information (tile_height) indicates the height of a tile. The height information may include information indicating the shape of the tile. For example, if the shape of the tile in top view is rectangular, the information may indicate the lengths of the sides of the rectangle (the vertical length and the horizontal length). Furthermore, if the shape of the tile in top view is circular, the information may indicate the diameter or radius of the circle.

[0360] The height information may indicate the height of each tile, or may indicate a common height for multiple tiles. Multiple height types, such as roads and intersections, may be set in advance, and the height information may indicate the height of each height type and the height type of each tile. Alternatively, the height of each height type may be defined in advance, and the height information may indicate the height type of each tile. In other words, the height of each height type does not have to be indicated by the height information.

[0361] The tile number (tile_number) indicates the number of tiles. The tile additional information may include information indicating the spacing between tiles.

[0362] The tile position information (global_position, relative_position) is information for identifying the position of each tile. For example, the tile position information indicates the absolute coordinates or relative coordinates of each tile.

[0363] Note that some or all of the above information may be provided for each tile, or for each set of tiles (for example, for each frame or for each set of frames).

[0364] The three-dimensional data encoding device may include the tile additional information in SEI (Supplemental Enhancement Information) and transmit it. Alternatively, the three-dimensional data encoding device may store the tile additional information in an existing parameter set (such as PPS, GPS, or APS) and transmit it.

[0365] For example, if the tile additional information changes for each frame, the tile additional information may be stored in a parameter set for each frame (GPS or APS, etc.). If the tile additional information does not change within a sequence, the tile additional information may be stored in a parameter set for each sequence (position SPS or attribute SPS). Furthermore, if the same tile division information is used for position information and attribute information, the tile additional information may be stored in a parameter set of a PCC stream (stream PS).

[0366] Furthermore, the tile additional information may be stored in any one of the above parameter sets, or in multiple parameter sets. Furthermore, the tile additional information may be stored in a header of the encoded data. Furthermore, the tile additional information may be stored in a header of a NAL unit.

[0367] In addition, all or part of the tile additional information may be stored in one of the headers of the divided position information and the divided attribute information, and not in the other. For example, when the same tile additional information is used in the position information and the attribute information, the tile additional information may be included in the header of either the position information or the attribute information. For example, when the attribute information depends on the position information, the position information is processed first. Therefore, the header of the position information may include these tile additional information, and the header of the attribute information may not include the tile additional information. In this case, the three-dimensional data decoding device determines, for example, that the dependent attribute information belongs to the same tile as the tile of the dependent position information.

[0368] The three-dimensional data decoding device reconstructs the point cloud data divided into tiles based on the tile additional information. If there is overlapping point cloud data, the three-dimensional data decoding device identifies the overlapping multiple point cloud data and selects one of them or merges the multiple point cloud data.

[0369] The three-dimensional data decoding device may also perform decoding using tile additional information. For example, when multiple tiles overlap, the three-dimensional data decoding device may perform decoding for each tile, and perform processing (e.g., smoothing or filtering) using the multiple decoded data to generate point cloud data. This may enable highly accurate decoding.

[0370] 59 is a diagram showing an example of the configuration of a system including a three-dimensional data encoding device and a three-dimensional data decoding device. A tile dividing unit 5051 divides point cloud data including position information and attribute information into a first tile and a second tile. The tile dividing unit 5051 also sends tile additional information related to the tile division to a decoding unit 5053 and a tile combining unit 5054.

[0371] The encoding unit 5052 generates encoded data by encoding the first tile and the second tile.

[0372] The decoding unit 5053 restores the first tile and the second tile by decoding the coded data generated by the coding unit 5052. The tile combining unit 5054 restores the point cloud data (position information and attribute information) by combining the first tile and the second tile using the tile additional information.

[0373] Next, slice additional information will be described. The three-dimensional data encoding device generates slice additional information, which is metadata related to a method of dividing a slice, and transmits the generated slice additional information to the three-dimensional data decoding device.

[0374] Fig. 60 is a diagram showing an example of the syntax of slice additional information (SliceMetaData). As shown in Fig. 60, for example, the slice additional information includes division method information (type_of_divide), an overlap flag (slice_overlap_flag), overlap information (type_of_overlap), the number of slices (slice_number), slice position information (global_position, relative_position), and slice size information (slice_bounding_box_size).

[0375] The division method information (type_of_divide) indicates a division method of a slice. For example, the division method information indicates whether the division method of a slice is division based on object information as shown in FIG. 50 (object). The slice additional information may include information indicating a method of object division. For example, this information indicates whether one object is divided into multiple slices or assigned to one slice. This information may also indicate the number of divisions when one object is divided into multiple slices.

[0376] The overlap flag (slice_overlap_flag) indicates whether the slices overlap. The overlap information (type_of_overlap) is included in the slice additional information when the slices overlap, for example. The overlap information indicates how the slices overlap, etc. For example, the overlap information indicates the size of the overlapping area, etc.

[0377] The slice number (slice_number) indicates the number of slices.

[0378] Slice position information (global_position, relative_position) and slice size information (slice_bounding_box_size) are information related to the area of ​​a slice. Slice position information is information for identifying the position of each slice. For example, slice position information indicates absolute coordinates or relative coordinates of each slice. Slice size information (slice_bounding_box_size) indicates the size of each slice. For example, slice size information indicates the size of the bounding box of each slice.

[0379] The three-dimensional data encoding device may include the slice additional information in the SEI and transmit it. Alternatively, the three-dimensional data encoding device may store the slice additional information in an existing parameter set (such as PPS, GPS, or APS) and transmit it.

[0380] For example, when slice additional information changes for each frame, the slice additional information may be stored in a parameter set for each frame (GPS or APS, etc.). When slice additional information does not change within a sequence, the slice additional information may be stored in a parameter set for each sequence (position SPS or attribute SPS). Furthermore, when the same slice division information is used for position information and attribute information, the slice additional information may be stored in a parameter set of a PCC stream (stream PS).

[0381] Furthermore, the slice additional information may be stored in any one of the above parameter sets, or in a plurality of parameter sets. Furthermore, the slice additional information may be stored in a header of the encoded data. Furthermore, the slice additional information may be stored in a header of the NAL unit.

[0382] In addition, all or a part of the slice additional information may be stored in one of the headers of the division position information and the header of the division attribute information, and may not be stored in the other. For example, when the same slice additional information is used in the position information and the attribute information, the slice additional information may be included in the header of one of the position information and the attribute information. For example, when the attribute information depends on the position information, the position information is processed first. Therefore, the header of the position information may include these slice additional information, and the header of the attribute information may not include the slice additional information. In this case, the three-dimensional data decoding device determines that the dependent attribute information belongs to the same slice as the slice of the dependent position information, for example.

[0383] The three-dimensional data decoding device reconstructs the point cloud data divided into slices based on the slice additional information. If there is overlapping point cloud data, the three-dimensional data decoding device identifies the overlapping multiple point cloud data and selects one of them or merges the multiple point cloud data.

[0384] The three-dimensional data decoding device may also perform decoding using slice additional information. For example, when multiple slices overlap, the three-dimensional data decoding device may perform decoding for each slice, and perform processing (e.g., smoothing or filtering) using the multiple decoded data to generate point cloud data. This may enable highly accurate decoding.

[0385] FIG. 61 is a flowchart of three-dimensional data encoding processing, including processing for generating tile additional information, performed by the three-dimensional data encoding device according to this embodiment.

[0386] First, the three-dimensional data encoding device determines a tile division method (S5031). Specifically, the three-dimensional data encoding device determines whether to use a division method based on a top view (top_view) or another method (other) as a tile division method. The three-dimensional data encoding device also determines the shape of the tile when using a division method based on a top view. The three-dimensional data encoding device also determines whether the tile overlaps with other tiles.

[0387] If the tile division method determined in step S5031 is a division method based on a top view (Yes in S5032), the three-dimensional data encoding device describes in the tile additional information that the tile division method is a division method based on a top view (top_view) (S5033).

[0388] On the other hand, if the tile division method determined in step S5031 is other than a division method based on a top view (No in S5032), the three-dimensional data encoding device describes in the tile additional information that the tile division method is other than a division method based on a top view (top_view) (S5034).

[0389] Furthermore, if the shape of the tile viewed from above determined in step S5031 is a square (square in S5035), the three-dimensional data encoding device records in the tile additional information that the shape of the tile viewed from above is a square (S5036).On the other hand, if the shape of the tile viewed from above determined in step S5031 is a circle (circle in S5035), the three-dimensional data encoding device records in the tile additional information that the shape of the tile viewed from above is a circle (S5037).

[0390] Next, the three-dimensional data encoding device determines whether the tile overlaps with other tiles (S5038). If the tile overlaps with other tiles (Yes in S5038), the three-dimensional data encoding device records in the tile additional information that the tile overlaps (S5039). On the other hand, if the tile does not overlap with other tiles (No in S5038), the three-dimensional data encoding device records in the tile additional information that the tile does not overlap (S5040).

[0391] Next, the three-dimensional data encoding device divides the tiles based on the tile division method determined in step S5031, encodes each tile, and transmits the generated encoded data and tile additional information (S5041).

[0392] FIG. 62 is a flowchart of three-dimensional data decoding processing using tile additional information by the three-dimensional data decoding device according to this embodiment.

[0393] First, the 3D data decoding device analyzes the tile additional information included in the bitstream (S5051).

[0394] If the tile additional information indicates that the tile does not overlap with other tiles (No in S5052), the 3D data decoding device generates point cloud data for each tile by decoding each tile (S5053). Next, the 3D data decoding device reconstructs point cloud data from the point cloud data for each tile based on the tile division method and tile shape indicated in the tile additional information (S5054).

[0395] On the other hand, if the tile additional information indicates that the tile overlaps with other tiles (Yes in S5052), the three-dimensional data decoding device generates point cloud data for each tile by decoding each tile. The three-dimensional data decoding device also identifies overlapping parts of the tiles based on the tile additional information (S5055). Note that the three-dimensional data decoding device may perform decoding processing for the overlapping parts using multiple pieces of overlapping information. Next, the three-dimensional data decoding device reconstructs point cloud data from the point cloud data of each tile based on the tile division method, tile shape, and overlap information indicated in the tile additional information (S5056).

[0396] Modifications and the like regarding slices will be described below. The three-dimensional data encoding device may transmit information indicating the type (road, building, tree, etc.) or attribute (dynamic information, static information, etc.) of an object as additional information. Alternatively, encoding parameters may be predefined according to the object, and the three-dimensional data encoding device may notify the three-dimensional data decoding device of the encoding parameters by sending the type or attribute of the object.

[0397] The following methods may be used for the coding order and transmission order of slice data. For example, the three-dimensional data encoding device may encode slice data in the order of data that is easiest to recognize or cluster. Alternatively, the three-dimensional data encoding device may encode slice data in the order of slice data that has been clustered first. Furthermore, the three-dimensional data encoding device may transmit the encoded slice data in the order of decreasing priority for decoding in an application. For example, when the priority of decoding dynamic information is high, the three-dimensional data encoding device may transmit the slice data in the order of decreasing priority for decoding dynamic information.

[0398] Furthermore, when the order of the encoded data differs from the order of the decoding priority, the three-dimensional data encoding device may rearrange the encoded data before transmitting it. Furthermore, when storing the encoded data, the three-dimensional data encoding device may store the encoded data after rearranging it.

[0399] An application (a three-dimensional data decoding device) requests a server (a three-dimensional data encoding device) to transmit slices containing desired data. The server transmits slice data required by the application, but does not need to transmit unnecessary slice data.

[0400] An application requests the server to send tiles containing desired data. The server sends the tile data required by the application, but does not need to send unnecessary tile data.

[0401] As described above, the three-dimensional data encoding device according to this embodiment performs the process shown in Fig. 63. First, the three-dimensional data encoding device generates a plurality of encoded data by encoding a plurality of subspaces (e.g., tiles) obtained by dividing a target space including a plurality of three-dimensional points (S5061). The three-dimensional data encoding device generates a bitstream including the plurality of encoded data and first information (e.g., topview_shape) indicating the shapes of the plurality of subspaces (S5062).

[0402] According to this, the three-dimensional data encoding device can select any shape from a plurality of types of subspace shapes, thereby improving encoding efficiency.

[0403] For example, the shape is a two-dimensional shape or a three-dimensional shape of the multiple subspaces. For example, the shape is a top view shape of the multiple subspaces. That is, the first information indicates a shape of the subspace when viewed from a specific direction (e.g., from above). In other words, the first information indicates a bird's-eye view shape of the subspace. For example, the shape is a rectangle or a circle.

[0404] For example, the bitstream includes second information (eg, tile_overlap_flag) indicating whether the multiple sub-intervals overlap.

[0405] According to this, the three-dimensional data encoding device can overlap the subspaces, so that the subspaces can be generated without complicating the shapes of the subspaces.

[0406] For example, the bitstream includes third information (eg, type_of_divide) indicating whether the division method for the plurality of sub-sections is a division method using a top view.

[0407] For example, the bitstream includes fourth information (eg, tile_height) indicating at least one of a height, a width, a depth, and a radius of the plurality of sub-sections.

[0408] For example, the bitstream includes fifth information (eg, global_position or relative_position) indicating a position of each of the plurality of sub-sections.

[0409] For example, the bitstream includes sixth information (eg, tile_number) indicating the number of the plurality of subintervals.

[0410] For example, the bit stream includes seventh information indicating intervals between the plurality of sub-intervals.

[0411] For example, the three-dimensional data encoding device includes a processor and a memory, and the processor uses the memory to perform the above-mentioned processing.

[0412] Moreover, the three-dimensional data decoding device according to this embodiment performs the process shown in FIG. 64. First, the three-dimensional data decoding device restores the multiple subspaces by decoding multiple encoded data generated by encoding multiple subspaces (e.g., tiles) obtained by dividing an object space including multiple three-dimensional points and included in a bit stream (S5071). The three-dimensional data decoding device restores the object space by combining the multiple subspaces using first information (e.g., topview_shape) included in the bit stream and indicating the shapes of the multiple subspaces (S5072). For example, the three-dimensional data decoding device can recognize the shapes of the multiple subspaces using the first information, thereby grasping the position and range of each subspace in the object space. The three-dimensional data decoding device can combine the multiple subspaces based on the grasped positions and ranges of the multiple subspaces. This allows the three-dimensional data decoding device to correctly combine the multiple subspaces.

[0413] For example, the shape is a shape in two dimensions of the subspaces, or a shape in three dimensions, for example, the shape is a rectangle or a circle.

[0414] For example, the bitstream includes second information (e.g., tile_overlap_flag) indicating whether the multiple subintervals overlap. In restoring the target space, the three-dimensional data decoding device further uses the second information to combine the multiple subspaces. For example, the three-dimensional data decoding device uses the second information to determine whether the subspaces overlap. If the subspaces overlap, the three-dimensional data decoding device identifies an overlapping area and takes a predetermined action for the identified overlapping area.

[0415] For example, the bit stream includes third information (e.g., type_of_divide) indicating whether the division method of the sub-intervals is a division method using a top view. When the third information indicates that the division method of the sub-intervals is a division method using a top view, the three-dimensional data decoding device combines the sub-spaces using the first information.

[0416] For example, the bitstream includes fourth information (e.g., tile_height) indicating at least one of height, width, depth, and radius of the plurality of subsections. In restoring the target space, the three-dimensional data decoding device further uses the fourth information to combine the plurality of subspaces. For example, the three-dimensional data decoding device can recognize the heights of the plurality of subspaces using the fourth information, thereby grasping the position and range of each subspace in the target space. The three-dimensional data decoding device can combine the plurality of subspaces based on the grasped positions and ranges of the plurality of subspaces.

[0417] For example, the bit stream includes fifth information (e.g., global_position or relative_position) indicating a position of each of the plurality of subintervals. In restoring the target space, the three-dimensional data decoding device further uses the fifth information to combine the plurality of subspaces. For example, the three-dimensional data decoding device can grasp the position of each subspace in the target space by recognizing the positions of the plurality of subspaces using the fifth information. The three-dimensional data decoding device can combine the plurality of subspaces based on the grasped positions of the plurality of subspaces.

[0418] For example, the bitstream includes sixth information (e.g., tile_number) indicating the number of the plurality of subintervals. In the reconstruction of the object space, the 3D data decoding device further uses the sixth information to combine the plurality of subspaces.

[0419] For example, the bit stream includes seventh information indicating intervals between the plurality of subintervals. In restoring the target space, the three-dimensional data decoding device further uses the seventh information to combine the plurality of subspaces. For example, the three-dimensional data decoding device can recognize the intervals between the plurality of subspaces using the seventh information, thereby grasping the position and range of each subspace in the target space. The three-dimensional data decoding device can combine the plurality of subspaces based on the grasped positions and ranges of the plurality of subspaces.

[0420] For example, the three-dimensional data decoding device includes a processor and a memory, and the processor uses the memory to perform the above-mentioned processing.

[0421] (Embodiment 7) In this embodiment, processing of division units (for example, tiles or slices) that do not include points will be described. First, a method of dividing point cloud data will be described.

[0422] In video coding standards such as HEVC, data exists for every pixel in a two-dimensional image, so even if a two-dimensional space is divided into multiple data regions, data exists in every data region. On the other hand, in coding of three-dimensional point cloud data, the points that are elements of the point cloud data are themselves data, and there is a possibility that data does not exist in some regions.

[0423] There are various methods for spatially dividing point cloud data, but the division methods can be classified according to whether a division unit (for example, a tile or slice), which is a divided data unit, always contains one or more point data.

[0424] A division method in which all of the division units contain one or more point data is called a first division method. For example, the first division method is a method in which the point cloud data is divided while considering the encoding processing time or the size of the encoded data. In this case, the number of points in each division unit is roughly equal.

[0425] Fig. 65 is a diagram showing an example of a division method. For example, as a first division method, a method of dividing points belonging to the same space into two identical spaces as shown in (a) of Fig. 65 may be used. Also, as shown in (b) of Fig. 65, a space may be divided into a plurality of subspaces (division units) such that each division unit includes a point.

[0426] These methods are point-aware divisions, so every division unit always contains at least one point.

[0427] A division method in which multiple division units may include one or more division units that do not contain point data is called a second division method. For example, as the second division method, a method of equally dividing the space can be used, as shown in (c) of Figure 65. In this case, points do not necessarily exist in the division units. In other words, there are cases in which no points exist in the division units.

[0428] When a three-dimensional data encoding device divides point cloud data, it may indicate in division additional information (metadata) related to the division (e.g., tile additional information or slice additional information) whether (1) a division method was used in which all of the multiple division units include one or more point data, (2) a division method was used in which the multiple division units have one or more division units that do not include point data, or (3) a division method was used in which the multiple division units may have one or more division units that do not include point data, and send out the division additional information.

[0429] The three-dimensional data encoding device may indicate the above information as the type of division method. Also, the three-dimensional data encoding device may perform division using a predetermined division method and not transmit the division additional information. In that case, the three-dimensional data encoding device indicates in advance whether the division method is the first division method or the second division method.

[0430] The second division method and an example of generating and transmitting encoded data will be described below. Note that, although tile division will be described as an example of a method of dividing a three-dimensional space, the following technique can also be applied to a division method using a division unit other than tiles. For example, tile division may be read as slice division.

[0431] Fig. 66 is a diagram showing an example of dividing point cloud data into six tiles. Fig. 66 shows an example in which the minimum unit is a point, and shows an example in which position information (Geometry) and attribute information (Attribute) are divided together. Note that the same applies when the position information and attribute information are divided by different division methods or division numbers, when there is no attribute information, and when there are multiple pieces of attribute information.

[0432] In the example shown in Figure 66, after tile division, there are tiles (#1, #2, #4, #6) that contain points and tiles (#3, #5) that do not contain points. Tiles that do not contain points are called null tiles.

[0433] Note that the division is not limited to six tiles, and any division method may be used. For example, the division unit may be a cube, or may be a non-cubic shape such as a rectangular parallelepiped or a cylinder. The multiple division units may have the same shape, or may include different shapes. In addition, a predetermined method may be used as the division method, or a different method may be used for each predetermined unit (e.g., PCC frame).

[0434] In this division method, when point cloud data is divided into tiles, if there is no data in a tile, a bitstream is generated that includes information indicating that the tile is a null tile.

[0435] Hereinafter, a method for transmitting null tiles and a method for signaling null tiles will be described. The three-dimensional data encoding device may generate, for example, the following information as additional information (metadata) related to data division, and transmit the generated information. Fig. 67 is a diagram showing an example of the syntax of tile additional information (TileMetaData). The tile additional information includes division method information (type_of_divide), division method null information (type_of_divide_null), number of tile divisions (number_of_tiles), and tile null flag (tile_null_flag).

[0436] The division method information (type_of_divide) is information related to the division method or division type. For example, the division method information indicates one or more division methods or division types. For example, the division method includes top view division and equal division. Note that when there is one division method definition, the division method information does not need to be included in the tile additional information.

[0437] The division method null information (type_of_divide_null) is information indicating whether the division method used is the first division method or the second division method described below. Here, the first division method is a division method in which all of the multiple division units always contain one or more point data. The second division method is a division method in which the multiple division units include one or more division units that do not contain point data, or in which the multiple division units may include one or more division units that do not contain point data.

[0438] The tile additional information may include, as division information for the entire tile, at least one of: (1) information indicating the number of divisions of the tile (number_of_tiles) or information for specifying the number of divisions of the tile, (2) information indicating the number of null tiles or information for specifying the number of null tiles, and (3) information indicating the number of tiles other than null tiles or information for specifying the number of tiles other than null tiles. The tile additional information may include, as division information for the entire tile, information indicating the shape of the tile or whether the tiles overlap.

[0439] Furthermore, the tile additional information indicates the division information for each tile in order. For example, the order of tiles is predetermined for each division method and is known in the three-dimensional data encoding device and the three-dimensional data decoding device. Note that, if the order of tiles is not predetermined, the three-dimensional data encoding device may send information indicating the order to the three-dimensional data decoding device.

[0440] The division information for each tile includes a tile null flag (tile_null_flag) that is a flag indicating whether or not data (points) exist in the tile. Note that if there is no data in the tile, the tile null flag may be included as the tile division information.

[0441] Furthermore, if the tile is not a null tile, the tile additional information includes division information for each tile (position information (e.g., coordinates of the origin (origin_x, origin_y, origin_z)) and height information of the tile, etc.). If the tile is a null tile, the tile additional information does not include division information for each tile.

[0442] For example, when slice division information for each tile is stored in the division information for each tile, the three-dimensional data encoding device does not need to store slice division information for null tiles in the additional information.

[0443] In this example, the number of tile divisions (number_of_tiles) indicates the number of tiles including null tiles. Fig. 68 is a diagram showing an example of tile index information (idx). In the example shown in Fig. 68, index information is also assigned to null tiles.

[0444] Next, a data structure and a transmission method of coded data including null tiles will be described. Figures 69 to 71 are diagrams showing data structures in the case where position information and attribute information are divided into six tiles and data does not exist in the third and fifth tiles.

[0445] FIG. 69 is a diagram showing an example of the dependency relationship of each data. The tip of the arrow in the figure indicates the dependency destination, and the base of the arrow indicates the dependency source. tn (n is 1 to 6) indicates the position information of tile number n, and A tn indicates the attribute information of tile number n. tile indicates tile additional information.

[0446] Fig. 70 is a diagram showing an example of the structure of transmission data, which is encoded data transmitted from a three-dimensional data encoding device. Fig. 71 is a diagram showing the structure of encoded data and a method of storing the encoded data in an NAL unit.

[0447] As shown in FIG. 71, the headers of the data of the position information (division position information) and the attribute information (division attribute information) each include tile index information (tile_idx).

[0448] Also, as shown in Structure 1 of Fig. 70, the three-dimensional data encoding device may not transmit position information or attribute information constituting a null tile. Alternatively, as shown in Structure 2 of Fig. 70, the three-dimensional data encoding device may transmit information indicating that the tile is a null tile as data of the null tile. For example, the three-dimensional data encoding device may indicate that the type of the data is a null tile in the tile_type stored in the header of the NAL unit or in the header in the payload (nal_unit_payload) of the NAL unit, and transmit the header. Note that the following description will be given assuming Structure 1.

[0449] In structure 1, when a null tile exists, the value of the tile index information (tile_idx) included in the header of the position information data or attribute information data in the transmission data is not consecutive and has gaps.

[0450] Furthermore, when there is a dependency between data, the three-dimensional data encoding device transmits the data so that the referenced data can be decoded before the referenced data. Note that the attribute information tiles have a dependency on the position information tiles. The attribute information and position information that have a dependency are assigned the same tile index number.

[0451] In addition, the tile additional information related to the tile division may be stored in both the parameter set of the position information (GPS) and the parameter set of the attribute information (APS), or in either one of them. When the tile additional information is stored in one of the GPS and the APS, reference information indicating the referenced GPS or APS may be stored in the other of the GPS and the APS. Furthermore, when the tile division method differs between the position information and the attribute information, different tile additional information is stored in the GPS and the APS, respectively. Furthermore, when the tile division method is the same for a sequence (multiple PCC frames), the tile additional information may be stored in the GPS, the APS, or the SPS (sequence parameter set).

[0452] For example, when tile additional information is stored in both the GPS and the APS, the tile additional information of position information is stored in the GPS, and the tile additional information of attribute information is stored in the APS. When tile additional information is stored in common information such as an SPS, tile additional information commonly used in the position information and the attribute information may be stored, or the tile additional information of position information and the tile additional information of attribute information may be stored separately.

[0453] A combination of tile division and slice division will be described below. First, a data structure and data transmission in the case where tile division is performed after slice division will be described.

[0454] Fig. 72 is a diagram showing an example of the dependency relationship of each piece of data when dividing into tiles after dividing into slices. The tip of the arrow in the diagram indicates the dependency destination, and the base of the arrow indicates the dependency source. In addition, data shown with a solid line in the diagram is data that is actually transmitted, and data shown with a dotted line is data that is not transmitted.

[0455] In the figure, G indicates location information, and A indicates attribute information. s1 indicates the position information of slice number 1, and G s2 indicates the position information of slice number 2. s1t1 indicates the position information of slice number 1 and tile number 1, and G s2t2 indicates the position information of slice number 2 and tile number 2. Similarly, A s1 indicates the attribute information of slice number 1, and A s2 indicates the attribute information of slice number 2. s1t1 indicates the attribute information of slice number 1 and tile number 1, and A s2t1 indicates attribute information of slice number 2 and tile number 1.

[0456] Mslice indicates slice additional information, MGtile indicates position tile additional information, and MAtile indicates attribute tile additional information. s1t1 is attribute information A s1t1 D s2t1 is attribute information As2t1 This shows dependency information for

[0457] The three-dimensional data encoding device does not need to generate and transmit position information and attribute information related to null tiles.

[0458] Even if the number of tile divisions is the same for all slices, the number of tiles generated and transmitted between slices may differ. For example, if the number of tile divisions differs between the position information and the attribute information, null tiles may exist in either the position information or the attribute information, but not in the other. In the example shown in FIG. 72, the position information (G s1 ) is G s1t1 and G s1t2 It is divided into two tiles, G s1t2 is a null tile. On the other hand, the attribute information of slice 1 (A s1 ) is not divided and is one A s1t1 exists and there is no null tile.

[0459] Furthermore, the three-dimensional data encoding device generates and transmits dependency information of the attribute information when data exists at least in the tile of the attribute information, regardless of whether or not a null tile is included in the slice of the position information. For example, when the three-dimensional data encoding device stores information on slice division for each tile in division information for each slice included in slice additional information related to slice division, the three-dimensional data encoding device stores information on whether the tile is a null tile in this information.

[0460] FIG. 73 is a diagram showing an example of the data decoding order. In the example of FIG. 73, decoding is performed in order from the data on the left. When data has a dependency relationship, the three-dimensional data decoding device decodes the dependent data first. For example, the three-dimensional data encoding device rearranges the data in advance so that the data is in this order, and transmits it. Any order may be used as long as the dependent data comes first. Furthermore, the three-dimensional data encoding device may transmit additional information and dependency information before the data.

[0461] Next, a data structure and data transmission in the case where slice division is performed after tile division will be described.

[0462] Fig. 74 is a diagram showing an example of the dependency relationship of each piece of data when dividing into slices after dividing into tiles. The tip of the arrow in the diagram indicates the dependency destination, and the base of the arrow indicates the dependency source. In addition, data shown with a solid line in the diagram is data that is actually sent, and data shown with a dotted line is data that is not sent.

[0463] In the figure, G indicates location information, and A indicates attribute information. t1 indicates the position information of tile number 1. t1s1 indicates the position information of tile number 1 and slice number 1, and G t1s2 indicates the position information of tile number 1 and slice number 2. Similarly, A t1 indicates the attribute information of tile number 1, and A t1s1 indicates attribute information of tile number 1 and slice number 1.

[0464] Mtile indicates tile additional information, MGslice indicates position slice additional information, and MAslice indicates attribute slice additional information. t1s1 is attribute information A t1s1 D t2s1 is attribute information A t2s1 This shows dependency information for

[0465] The three-dimensional data encoding device does not divide null tiles into slices, and does not need to generate and transmit position information, attribute information, and dependency information of attribute information related to null tiles.

[0466] FIG. 75 is a diagram showing an example of the data decoding order. In the example of FIG. 75, decoding is performed in order from the left data. When data has a dependency relationship, the three-dimensional data decoding device decodes the dependent data first. For example, the three-dimensional data encoding device rearranges the data in advance so as to achieve this order, and transmits the data. Any order may be used as long as the dependent data comes first. The three-dimensional data encoding device may also transmit additional information and dependency information before the data.

[0467] Next, a flow of a process of dividing and combining point cloud data will be described. Note that although an example of dividing into tiles and slices will be described here, a similar method can be applied to dividing other spaces.

[0468] Fig. 76 is a flowchart of three-dimensional data encoding processing including data division processing by a three-dimensional data encoding device. First, the three-dimensional data encoding device determines the division method to be used (S5101). Specifically, the three-dimensional data encoding device determines whether to use the first division method or the second division method. For example, the three-dimensional data encoding device may determine the division method based on a designation from a user or an external device (e.g., a three-dimensional data decoding device), or may determine the division method according to input point cloud data. In addition, the division method to be used may be predetermined.

[0469] Here, the first division method is a division method in which all of the multiple division units (tiles or slices) always contain one or more point data, and the second division method is a division method in which the multiple division units include one or more division units that do not include point data, or there is a possibility that the multiple division units include one or more division units that do not include point data.

[0470] If the determined division method is the first division method (first division method in S5102), the three-dimensional data encoding device describes that the division method used is the first division method in the division additional information (e.g., tile additional information or slice additional information), which is metadata related to data division (S5103).Then, the three-dimensional data encoding device encodes all division units (S5104).

[0471] On the other hand, if the determined division method is the second division method (second division method in S5102), the three-dimensional data encoding device describes in the division additional information that the division method used is the second division method (S5105).Then, the three-dimensional data encoding device encodes the division units, excluding the division units that do not include point data (e.g., null tiles), among the multiple division units (S5106).

[0472] 77 is a flowchart of a three-dimensional data decoding process including a data splicing process by a three-dimensional data decoding device. First, the three-dimensional data decoding device refers to the partitioning additional information included in the bitstream, and determines whether the partitioning method used is the first partitioning method or the second partitioning method (S5111).

[0473] If the division method used is the first division method (first division method in S5112), the three-dimensional data decoding device receives the encoded data of all division units and generates decoded data of all division units by decoding the received encoded data (S5113). Next, the three-dimensional data decoding device reconstructs a three-dimensional point cloud using the decoded data of all division units (S5114). For example, the three-dimensional data decoding device reconstructs a three-dimensional point cloud by combining multiple division units.

[0474] On the other hand, if the division method used is the second division method (second division method in S5112), the three-dimensional data decoding device receives the coded data of the division units including point data and the coded data of the division units not including point data, and generates decoded data by decoding the coded data of the received division units (S5115). Note that, if a division unit not including point data is not sent, the three-dimensional data decoding device does not need to receive and decode a division unit not including point cloud data. Next, the three-dimensional data decoding device reconstructs a three-dimensional point cloud using the decoded data of the division units including point data (S5116). For example, the three-dimensional data decoding device reconstructs a three-dimensional point cloud by combining a plurality of division units.

[0475] Other methods of dividing point cloud data will be described below. When dividing a space evenly as shown in (c) of Fig. 65, there are cases where no points exist in the divided spaces. In this case, the three-dimensional data encoding device combines the space where no points exist with another space where points exist. In this way, the three-dimensional data encoding device can form multiple division units so that all division units include one or more points.

[0476] 78 is a flowchart of data division in this case. First, the three-dimensional data encoding device divides the data in a specific method (S5121). For example, the specific method is the second division method described above.

[0477] Next, the three-dimensional data encoding device determines whether or not a point is included in the target division unit, which is the division unit to be processed (S5122). If a point is included in the target division unit (Yes in S5122), the three-dimensional data encoding device encodes the target division unit (S5123). On the other hand, if a point is not included in the target division unit (No in S5122), the three-dimensional data encoding device combines the target division unit with other division units that include points, and encodes the combined division unit (S5124). In other words, the three-dimensional data encoding device encodes the target division unit together with other division units that include points.

[0478] Although the example of performing the determination and combination for each division unit has been described here, the processing method is not limited to this. For example, the three-dimensional data encoding device may determine whether or not each of the multiple division units includes a point, combine the multiple division units so that there is no division unit that does not include a point, and encode each of the multiple division units after the combination.

[0479] Next, a method for transmitting data including null tiles will be described. If the target tile to be processed is a null tile, the three-dimensional data encoding device does not transmit data of the target tile. Figure 79 is a flowchart of the data transmission process.

[0480] First, the three-dimensional data encoding device determines a tile division method, and divides the point cloud data into tiles using the determined division method (S5131).

[0481] Next, the three-dimensional data encoding device determines whether or not the target tile is a null tile (S5132), that is, whether or not there is no data in the target tile.

[0482] If the target tile is a null tile (Yes in S5132), the three-dimensional data encoding device indicates that the target tile is a null tile in the tile additional information, and does not indicate information about the target tile (such as the tile's position and size) (S5133).In addition, the three-dimensional data encoding device does not send out the target tile (S5134).

[0483] On the other hand, if the target tile is not a null tile (No in S5132), the three-dimensional data encoding device indicates in the tile additional information that the target tile is not a null tile and indicates information for each tile (S5135).The three-dimensional data encoding device also outputs the target tile (S5136).

[0484] In this way, by not including information about null tiles in the tile additional information, the amount of information in the tile additional information can be reduced.

[0485] A method for decoding coded data including null tiles will be described below. First, a process for when there is no packet loss will be described.

[0486] 80 is a diagram showing an example of transmission data, which is encoded data transmitted from a three-dimensional data encoding device, and reception data input to a three-dimensional data decoding device. Note that, here, a system environment without packet loss is assumed, and the reception data is the same as the transmission data.

[0487] In the case of a system environment without packet loss, the three-dimensional data decoding device receives all of the transmitted data. Figure 81 is a flowchart of the process performed by the three-dimensional data decoding device.

[0488] First, the three-dimensional data decoding device refers to the tile additional information (S5141), and determines whether or not each tile is a null tile (S5142).

[0489] If the tile additional information indicates that the target tile is not a null tile (No in S5142), the 3D data decoding device determines that the target tile is not a null tile and decodes the target tile (S5143). Next, the 3D data decoding device obtains tile information (tile position information (origin coordinates, etc.) and size, etc.) from the tile additional information, and reconstructs 3D data by combining multiple tiles using the obtained information (S5144).

[0490] On the other hand, if the tile additional information indicates that the target tile is not a null tile (Yes in S5142), the three-dimensional data decoding device determines that the target tile is a null tile and does not decode the target tile (S5145).

[0491] The three-dimensional data decoding device may determine that missing data is a null tile by sequentially analyzing index information indicated in the header of the encoded data. The three-dimensional data decoding device may also combine a determination method using tile additional information and a determination method using index information.

[0492] Next, the process when packet loss occurs will be described. Figure 82 is a diagram showing an example of data sent from a three-dimensional data encoding device and data received by a three-dimensional data decoding device. Here, a system environment with packet loss is assumed.

[0493] In a system environment with packet loss, the 3D data decoding device may not be able to receive all of the transmitted data. t2 and A t2 packets are lost.

[0494] 83 is a flowchart of the process of the three-dimensional data decoding device in this case. First, the three-dimensional data decoding device analyzes the continuity of the index information indicated in the header of the encoded data (S5151), and determines whether the index number of the target tile exists (S5152).

[0495] If the index number of the target tile exists (Yes in S5152), the 3D data decoding device determines that the target tile is not a null tile, and performs a decoding process for the target tile (S5153). Next, the 3D data decoding device obtains tile information (tile position information (origin coordinates, etc.) and size, etc.) from the tile additional information, and reconstructs 3D data by combining multiple tiles using the obtained information (S5154).

[0496] On the other hand, if index information for the target tile does not exist (No in S5152), the 3D data decoding device determines whether or not the target tile is a null tile by referring to the tile additional information (S5155).

[0497] If the target tile is not a null tile (No in S5156), the three-dimensional data decoding device determines that the target tile has been lost (packet loss) and performs error decoding processing (S5157). The error decoding processing is, for example, processing that attempts to decode the original data assuming that the data exists. In this case, the three-dimensional data decoding device may reproduce the three-dimensional data and perform reconstruction of the three-dimensional data (S5154).

[0498] On the other hand, if the target tile is a null tile (Yes in S5156), the 3D data decoding device assumes that the target tile is a null tile and does not perform the decoding process or reconstruct the 3D data (S5158).

[0499] Next, a coding method in which null tiles are not explicitly indicated will be described. The three-dimensional data coding device may generate coded data and additional information in the following manner.

[0500] The three-dimensional data encoder does not indicate information about null tiles in the tile additional information. The three-dimensional data encoder adds index numbers of tiles other than null tiles to the data header. The three-dimensional data encoder does not send null tiles.

[0501] In this case, the number of tile divisions (number_of_tiles) indicates the number of divisions excluding null tiles. The three-dimensional data encoding device may store information indicating the number of null tiles separately in the bit stream. The three-dimensional data encoding device may also indicate information about null tiles in the additional information, or may indicate part of the information about null tiles.

[0502] 84 is a flowchart of the three-dimensional data encoding process by the three-dimensional data encoding device in this case. First, the three-dimensional data encoding device determines a tile division method, and divides the point cloud data into tiles using the determined division method (S5161).

[0503] Next, the three-dimensional data encoding device determines whether the target tile is a null tile (S5162), that is, whether there is no data in the target tile.

[0504] If the target tile is not a null tile (No in S5162), the three-dimensional data encoding device adds index information of tiles other than null tiles to the data header (S5163).Then, the three-dimensional data encoding device outputs the target tile (S5164).

[0505] On the other hand, if the target tile is a null tile (Yes in S5162), the three-dimensional data encoding device does not add index information of the target tile to the data header, and does not transmit the target tile.

[0506] Fig. 85 is a diagram showing an example of index information (idx) added to a data header. As shown in Fig. 85, index information for null tiles is not added, and consecutive numbers are added to tiles other than null tiles.

[0507] FIG. 86 is a diagram showing an example of the dependency relationship of each data. The tip of the arrow in the diagram indicates the dependency destination, and the base of the arrow indicates the dependency source. In addition, in the same figure, G tn (n is 1 to 4) indicates the position information of tile number n, and A tn indicates the attribute information of tile number n. tile indicates tile additional information.

[0508] FIG. 87 is a diagram showing an example of the structure of transmission data, which is encoded data transmitted from the three-dimensional data encoding device.

[0509] The following describes a decoding method when null tiles are not explicitly indicated. Figure 88 is a diagram showing an example of data sent from a three-dimensional data encoding device and data received by a three-dimensional data decoding device. Here, a system environment with packet loss is assumed.

[0510] 89 is a flowchart of the process of the three-dimensional data decoding device in this case. First, the three-dimensional data decoding device analyzes the tile index information indicated in the header of the encoded data, and determines whether the index number of the target tile exists. In addition, the three-dimensional data decoding device obtains the number of divisions of the tile from the tile additional information (S5171).

[0511] If the index number of the target tile exists (Yes in S5172), the 3D data decoding device performs a decoding process for the target tile (S5173). Next, the 3D data decoding device obtains tile information (tile position information (origin coordinates, etc.) and size, etc.) from the tile additional information, and reconstructs 3D data by combining multiple tiles using the obtained information (S5175).

[0512] On the other hand, if the index number of the target tile does not exist (No in S5172), the three-dimensional data decoding device determines that the target tile is a packet loss, and performs error decoding processing (S5174). In addition, the three-dimensional data decoding device determines that a space that does not exist in the data is a null tile, and reconstructs the three-dimensional data.

[0513] In addition, by explicitly indicating null tiles, the three-dimensional data encoding device can properly determine that no points exist within a tile, and that this is not due to measurement error or data loss due to data processing, etc., or packet loss.

[0514] The three-dimensional data encoding device may use both a method of explicitly indicating null packets and a method of not explicitly indicating null packets. In this case, the three-dimensional data encoding device may indicate information indicating whether or not null packets are explicitly indicated in the tile additional information. Also, whether or not null packets are explicitly indicated may be determined in advance according to the type of division method, and the three-dimensional data encoding device may indicate whether or not null packets are explicitly indicated by indicating the type of division method.

[0515] In addition, in Figure 67 etc., an example is shown in which the tile additional information indicates information related to all tiles, but the tile additional information may indicate information on some of the multiple tiles, or may indicate null tile information on some of the multiple tiles.

[0516] Also, an example has been described in which information about split data, such as information about whether or not split data (tiles) exists, is stored in the tile additional information, but some or all of this information may be stored in a parameter set or stored as data. When this information is stored as data, for example, nal_unit_type, which means information indicating whether or not split data exists, may be defined, and this information may be stored in the NAL unit. Also, this information may be stored in both the additional information and the data.

[0517] As described above, the three-dimensional data encoding device according to this embodiment performs the process shown in Fig. 90. First, the three-dimensional data encoding device generates a plurality of encoded data by encoding a plurality of subspaces (e.g., tiles or slices) obtained by dividing a target space including a plurality of three-dimensional points (S5181). The three-dimensional data encoding device generates a bitstream including the plurality of encoded data and first information (e.g., tile_null_flag) corresponding to each of the plurality of subspaces (S5182). Each of the plurality of first information indicates whether or not second information indicating the structure of the corresponding subspace is included in the bitstream.

[0518] According to this, for example, the second information can be omitted for subspaces that do not include points, so that the data amount of the bit stream can be reduced.

[0519] For example, the second information includes information indicating the coordinates of the origin of the corresponding subspace. For example, the second information includes information indicating at least one of the height, width, and depth of the corresponding subspace.

[0520] This enables the three-dimensional data encoding device to reduce the amount of data in the bit stream.

[0521] Also, as shown in Fig. 78, the three-dimensional data encoding device may divide a target space including a plurality of three-dimensional points into a plurality of subspaces (e.g., tiles or slices), combine the plurality of subspaces according to the number of three-dimensional points included in each subspace, and encode the combined subspaces. For example, the three-dimensional data encoding device may combine the plurality of subspaces such that the number of three-dimensional points included in each of the combined subspaces is equal to or greater than a predetermined number. For example, the three-dimensional data encoding device may combine a subspace that does not include a three-dimensional point with a subspace that includes a three-dimensional point.

[0522] According to this, the three-dimensional data encoding device can suppress the generation of a subspace having a small number of points or including no points, thereby improving encoding efficiency.

[0523] For example, the three-dimensional data encoding device includes a processor and a memory, and the processor uses the memory to perform the above-mentioned processing.

[0524] Moreover, the three-dimensional data decoding device according to this embodiment performs the process shown in FIG. 91. First, the three-dimensional data decoding device obtains from the bit stream a plurality of pieces of first information (e.g., tile_null_flag), each of which corresponds to a plurality of subspaces (e.g., tiles or slices) obtained by dividing an object space including a plurality of three-dimensional points and indicates whether or not second information indicating the structure of the corresponding subspace is included in the bit stream (S5191). Using the plurality of pieces of first information, the three-dimensional data decoding device (i) restores the plurality of subspaces by decoding a plurality of encoded data generated by encoding the plurality of subspaces included in the bit stream, and (ii) restores the object space by combining the plurality of subspaces (S5192). For example, the three-dimensional data decoding device uses the first information to determine whether or not second information is included in the bit stream, and if the bit stream includes the second information, uses the second information to combine the decoded plurality of subspaces.

[0525] According to this, for example, the second information can be omitted for subspaces that do not include points, so that the data amount of the bit stream can be reduced.

[0526] For example, the second information includes information indicating the coordinates of the origin of the corresponding subspace. For example, the second information includes information indicating at least one of the height, width, and depth of the corresponding subspace.

[0527] This enables the three-dimensional data decoding device to reduce the amount of data in the bit stream.

[0528] The three-dimensional data decoding device may also receive encoded data generated by dividing a target space including a plurality of three-dimensional points into a plurality of subspaces (e.g., tiles or slices), combining the plurality of subspaces according to the number of three-dimensional points included in each subspace, encoding the combined subspace, and decode the received encoded data. For example, the encoded data may be generated by combining the plurality of subspaces such that the number of three-dimensional points included in each of the combined subspaces is equal to or greater than a predetermined number. For example, the three-dimensional data may be generated by combining a subspace that does not include a three-dimensional point with a subspace that includes a three-dimensional point.

[0529] With this, the three-dimensional data device can decode coded data with improved coding efficiency by suppressing the generation of subspaces with a small number of points or containing no points.

[0530] For example, the three-dimensional data decoding device includes a processor and a memory, and the processor uses the memory to perform the above-mentioned processing.

[0531] (Embodiment 8) Fig. 92 is a block diagram showing an example of the configuration of a three-dimensional data encoding device according to this embodiment. Fig. 93 is a diagram for explaining an outline of an encoding method by the three-dimensional data encoding device according to this embodiment.

[0532] The three-dimensional data encoding device 6800 generates split data in which point cloud data is divided into a plurality of pieces, such as tiles or slices, and encodes each of the plurality of split data. The split data is also called sub-point cloud data. Point cloud data is data indicating a plurality of three-dimensional positions in a three-dimensional space. The plurality of split data are a plurality of sub-point cloud data obtained by dividing the three-dimensional space in which the point cloud data is arranged into a plurality of subspaces to divide the point cloud data into a plurality of pieces. The number of divisions, that is, the number of split data, may be 1, indicating no division, or may be 2 or more.

[0533] In addition, in Fig. 92, a configuration of a three-dimensional data encoding device 6800 that divides into two will be described as an example. In Fig. 93, an example of dividing point cloud data into four will be shown. In Fig. 93, the divided space will be described as a two-dimensional space as an example, but it may be a one-dimensional space or a three-dimensional space.

[0534] The three-dimensional data encoding device 6800 comprises a division method determination unit 6801, a division unit 6802, quantization units 6803a and 6803b, shift amount calculation units 6804a and 6804b, common position shift units 6805a and 6805b, individual position shift units 6806a and 6806b, and encoding units 6807a and 6807b.

[0535] The division method determination unit 6801 determines a division method for the point cloud data. The division method determination unit 6801 outputs division method information indicating the division method to the division unit 6802 and the shift amount calculation units 6804a and 6804b. A specific example of the division method will be described later. The three-dimensional data encoding device 6800 does not need to have the division method determination unit 6801. In this case, the three-dimensional data encoding device 6800 may divide the point cloud data into a plurality of divided data by a predetermined division method.

[0536] The dividing unit 6802 divides the point cloud data into a plurality of divided data according to the division method determined by the division method determining unit 6801. The plurality of divided data divided by the division unit 6802 are processed individually. For this reason, the three-dimensional data encoding device 6800 includes a processing unit that executes subsequent processing for each divided data. Specifically, the three-dimensional data encoding device 6800 includes a quantization unit 6803a, a shift amount calculation unit 6804a, a common position shift unit 6805a, an individual position shift unit 6806a, and an encoding unit 6807a for processing the first divided data. In addition, the three-dimensional data encoding device 6800 includes a quantization unit 6803b, a shift amount calculation unit 6804b, a common position shift unit 6805b, an individual position shift unit 6806b, and an encoding unit 6807b for processing the second divided data. This allows the three-dimensional data encoding device 6800 to execute processing for each of the multiple pieces of divided data in parallel. Note that, although Fig. 92 shows an example of the three-dimensional data encoding device 6800 having a processing unit that processes two pieces of divided data in parallel, the three-dimensional data encoding device 6800 may have a processing unit that processes three or more pieces of divided data in parallel. Also, the three-dimensional data encoding device may be configured to process each of the multiple pieces of divided data by a single processing unit.

[0537] Each of the quantization units 6803a and 6803b performs scaling (dividing the position information by an arbitrary value) and quantization on the corresponding divided data. When multiple points overlap, each of the quantization units 6803a and 6803b may delete at least one of the multiple overlapping points, or may not process the at least one point.

[0538] Each of the shift amount calculation units 6804a and 6804b shifts the position of the corresponding divided data, that is, calculates at least one of a common position shift amount and an individual position shift amount for moving the data, according to the division method determined by the division method determination unit 6801. The shift amount calculation units 6804a and 6804b calculate only the common position shift amount out of the common position shift amount and the individual position shift amount, calculate only the individual position shift amount, or calculate both the common position shift amount and the individual position shift amount, depending on the division method.

[0539] The common position shift amount is a shift amount (movement amount) by which the positions of the multiple divided data are commonly moved. In other words, the common position shift amount is the same for the multiple divided data. The common position shift amount includes a direction in which the positions of the multiple divided data are moved and a distance by which they are moved. The common position shift amount is an example of a first movement amount.

[0540] The individual position shift amount is a shift amount (movement amount) by which the position of each of the multiple divided data is moved individually. The individual position shift amount is a shift amount determined in one-to-one correspondence with each of the multiple divided data, and in many cases differs between the multiple divided data. The individual position shift amount includes a direction in which the position of the corresponding divided data is moved and a distance by which it is moved. The individual position shift amount is an example of a second movement amount.

[0541] Each of the common position shift units 6805a and 6805b executes a position shift on the corresponding divided data by the common position shift amount calculated by the shift amount calculation units 6804a and 6804b. As a result, the divided data 6811 to 6814 obtained by dividing the point cloud data 6810 shown in (a) of Fig. 93 move in the direction and by the distance indicated by the common position shift amount, as shown in (b) of Fig. 93.

[0542] Each of the individual position shifters 6806a and 6806b executes a position shift on the corresponding divided data by the individual position shift amount calculated by the shift amount calculators 6804a and 6804b. As a result, each of the divided data 6811 to 6814 shown in (c) of Fig. 93 moves in a direction and by a distance indicated by the corresponding individual shift amount.

[0543] Each of the encoding units 6807a and 6807b encodes a corresponding one of the multiple pieces of divided data shifted by the individual position shift units 6806a and 6806b.

[0544] The processing order of the division unit 6802, the quantization units 6803a and 6803b, the shift amount calculation units 6804a and 6804b, the common position shift units 6805a and 6805b, and the individual position shift units 6806a and 6806b may be interchanged. For example, the shift amount calculation units 6804a and 6804b and the common position shift units 6805a and 6805b may perform processing before the division unit 6802. In this case, the shift amount calculation units 6804a and 6804b may be merged into one processing unit, and the common position shift units 6805a and 6805b may be merged into one processing unit. In this case, the shift amount calculation units 6804a and 6804b may calculate at least the common position shift amount of the common position shift amount and the individual position shift amount before the common position shift units 6805a and 6805b, and the individual position shift amount may be calculated before the processing of the individual position shift units 6806a and 6806b. In other words, a configuration may be adopted in which a processing unit that calculates the common position shift amount is separate from a processing unit that calculates the individual position shift amount and calculates the common position shift amount before the common position shift unit. Also, any two or more processing units among the above-mentioned multiple processing units may be merged.

[0545] Next, a calculation example of a common position shift amount and an individual position shift amount will be described with reference to Fig. 94. Fig. 94 is a diagram for explaining a first example of a position shift. The first example is an example in which a point cloud data 6810 is shifted by a common position shift amount, and then a plurality of divided data 6811 to 6814 are shifted by the individual position shift amounts corresponding to each of them.

[0546] As shown in (a) of FIG. 94, the three-dimensional data encoding device generates a bounding box 6820 having a size including all the divided data 6811 to 6814 of the point cloud data 6810, and calculates the minimum point of the generated bounding box 6820. Then, the three-dimensional data encoding device calculates the direction and distance of a vector indicated by the difference between the calculated minimum point and the origin as a common position shift amount. Since the origin is 0, the difference is indicated by the coordinates of the minimum point. The origin may be a predetermined reference point other than 0. The bounding box 6820 may be a rectangular area of ​​a minimum size that surrounds all the divided data 6811 to 6814. The minimum point of the bounding box 6820 is the point closest to the origin in the bounding box 6820 area. The bounding box 6820 is also called a common bounding box. The bounding box is also called an encoding bounding box.

[0547] The three-dimensional data encoding device moves the multiple divided data 6811 to 6814 by the calculated common position shift amount, as shown in (b) of Fig. 94. Note that the three-dimensional data encoding device may move the point cloud data 6810 before division by the common position shift amount.

[0548] Next, as shown in (b) of FIG. 94, for each of the plurality of divided data 6811-6814 after the common position shift, the three-dimensional data encoding device generates bounding boxes 6821-6824 of a size including the divided data 6811-6814, and calculates the minimum point of each of the generated bounding boxes 6821-6824. Then, for each of the plurality of divided data 6811-6814, the three-dimensional data encoding device calculates the distance between the minimum point of the bounding box corresponding to the divided data and the origin as an individual position shift amount of the divided data. Each of the bounding boxes 6821-6824 may be a rectangular area of ​​a minimum size that surrounds the corresponding divided data 6811-6814. The minimum point of the bounding boxes 6821-6824 is the point closest to the origin in each of the bounding boxes 6821-6824. Each of the bounding boxes 6821 to 6824 is also referred to as an individual bounding box.

[0549] As shown in FIG. 94(c), the three-dimensional data encoding device moves each of the multiple divided data 6811 to 6814 by the calculated corresponding individual position shift amount.

[0550] The three-dimensional data encoding device generates a bitstream by encoding each of the multiple divided data 6811-6814 moved by the individual position shift amount using the corresponding bounding boxes 6821-6824. At this time, the three-dimensional data encoding device stores second bounding box information indicating the position and size of the minimum point of each of the bounding boxes 6821-6824 in metadata included in the bitstream. Note that, hereinafter, the bounding box is also referred to as an encoded bounding box (encoded BB).

[0551] The common position shift amount and the first bounding box information indicating the position and size of the minimum point of the bounding box 6820 are stored in the SPS of the data configuration of the bitstream shown in (e) of Fig. 94. The individual position shift amount is stored in the header of the position information of the corresponding divided data. The second bounding box information of the bounding boxes 6821-6824 used in encoding each of the divided data 6811-6814 is stored in the header of the position information of the corresponding divided data.

[0552] Here, if the common position shift amount is Shift_A and the individual position shift amount is Shift_B(i) (i is the index of the divided data), the shift amount Shift(i) of the divided data (i) can be calculated using the following formula.

[0553] Shift(i) = Shift_A + Shift_B(i)

[0554] That is, as shown in FIG. 94(d), the total shift amount of each divided data can be calculated by adding up the common position shift amount and the corresponding individual position shift amount.

[0555] Before encoding the point cloud data, the three-dimensional data encoding device shifts the position of the point cloud data of the i-th divided data by subtracting Shift(i).

[0556] The three-dimensional data decoding device obtains Shift_A and Shift_B(i) from the SPS and the headers of the divided data, calculates Shift(i), and then adds Shift(i) to the decoded divided data(i) to return the divided data to their original positions. This makes it possible to correctly restore multiple divided data.

[0557] Next, a second example of position shifting in which common position shifting is performed and individual position shifting is not performed will be described with reference to Figure 95. In the second example, the amount of information in the bit stream can be reduced since the amount of individual position shifting is not transmitted.

[0558] 95 is a diagram for explaining a second example of the position shift. In the second example, the position of the point cloud data 6810 is shifted by the common position shift amount, and the positions of the divided data 6811 to 6814 are not shifted by the individual position shift amount.

[0559] As shown in (a) of Fig. 95, the three-dimensional data encoding device generates a bounding box 6820 having a size that includes all divided data 6811 to 6814 of the point cloud data 6810, and calculates the common position shift amount using the generated bounding box 6820. The method of calculating the common position shift amount is the same as the method described using Fig. 94.

[0560] As shown in (b) of Figure 95, the three-dimensional data encoding device moves multiple divided data 6811-6814 by the calculated common position shift amount, and encodes using a bounding box 6820 that includes all of the divided data 6811-6814 after the common position shift.

[0561] In this way, in the second example, after dividing the point cloud data 6810, the individual position shift amount or bounding box information of each of the multiple divided data 6811-6814 is not calculated. Note that in the second example, the three-dimensional data encoding device shifts the positions of the multiple divided data 6811-6814 by a common position shift amount and encodes them using a common bounding box, but this is not limited to the above. For example, the three-dimensional data encoding device may shift the positions of the multiple divided data 6811-6814 by a common position shift amount and encode them using individual bounding boxes of each of the divided data 6811-6814. Also, the three-dimensional data encoding device may shift each of the divided data 6811-6814 by an individual position shift amount and encode them using a common bounding box.

[0562] As shown in FIG. 95(c), the total shift amount of each divided data is a common position shift amount.

[0563] In addition, the first bounding box information indicating the common position shift amount and the position and size of the minimum point of the bounding box 6820 including all the split data is stored in the SPS of the bitstream data structure shown in (d) of Figure 95.

[0564] On the other hand, the header of the position information of the corresponding divided data does not store the individual position shift amount and the second bounding box information used in encoding each divided data.

[0565] In addition, a flag (identification information) indicating that encoding was performed using a common position shift amount and a bounding box including all of the split data 6811 to 6814, and a flag (identification information) indicating that the individual position shift amount and the size information of the bounding box used in encoding the split data are not stored in the header of the position information for each split data are stored in the SPS or GPS.

[0566] Based on the above flag stored in the SPS or GPS, the three-dimensional data decoding device determines whether the data was encoded using common information or individual information, and calculates the location information and bounding box size to be used for decoding.

[0567] In the following description, BB indicates a bounding box. The common information is a common position shift amount and first BB information common to a plurality of divided data. The common position shift amount may be indicated by a minimum value point of the common bounding box. The individual information is an individual position shift amount for each divided data and second BB information of the bounding box for each divided data used for encoding. The individual position shift amount may be indicated by a minimum value point of the bounding box for each divided data. The divided region information is information indicating a division boundary in space when dividing data, and may include a minimum value point of the BB and BB information indicating the size of the BB.

[0568] Fig. 96 is a flowchart showing an example of an encoding method when switching between the first example and the second example. Fig. 97 is a flowchart showing an example of a decoding method when switching between the first example and the second example.

[0569] As shown in FIG. 96, the three-dimensional data encoding device determines a common position shift amount of the point cloud data 6810 and the size of a common BB surrounding the point cloud data 6810 (S6801).

[0570] The three-dimensional data encoding device determines whether or not to individually shift each of the divided data 6811 to 6814 using the individual position shift amount (S6802). The three-dimensional data encoding device may determine this based on the result of determining the amount of header information reduction or the encoding efficiency.

[0571] When each divided data 6811-6814 is not shifted individually (No in S6802), the three-dimensional data encoding device determines to send the common position shift amount and the size of the common BB (S6803), and determines not to send the individual position shift amount and the size of the common BB (S6804). As a result, the three-dimensional data encoding device generates a bit stream that includes the common position shift amount and the size of the common BB, but does not include the individual position shift amount and the size of the individual BB. The bit stream may store identification information indicating that the data is not shifted individually.

[0572] On the other hand, when shifting each of the divided data 6811-6814 individually (Yes in S6802), the three-dimensional data encoding device determines to transmit the common position shift amount and the size of the common BB (S6805), and also determines to transmit the individual position shift amount and the size of the individual BB (S6806). As a result, the three-dimensional data encoding device generates a bit stream including the common position shift amount and the size of the common BB, and also including the individual position shift amount and the size of the individual BB. The bit stream may store identification information indicating that the data is shifted individually. Note that the three-dimensional data encoding device may calculate the individual position shift amount and the individual BB size of each of the divided data 6811-6814 in step S6806.

[0573] As shown in FIG. 97, the three-dimensional data decoding device acquires the bit stream, and thereby acquires identification information indicating whether or not an individual shift has been performed (S6811).

[0574] The three-dimensional data decoding device uses the identification information to determine whether or not an individual shift was performed during encoding (S6812).

[0575] When it is determined that individual shifts have not been performed on each of the divided data 6811 to 6814 (No in S6812), the three-dimensional data decoding device acquires the common position shift amount and the size of the common BB from the bit stream (S6813).

[0576] On the other hand, if the three-dimensional data decoding device determines that individual shifts have been performed on each split data 6811 to 6814 (Yes in S6812), it obtains the common position shift amount and the size of the common BB from the bit stream (S6814), and also obtains the individual position shift amount and the size of the individual BB (S6815).

[0577] Next, a third example of performing a position shift by a position shift amount determined using a divided area of ​​a space in which point cloud data exists will be described with reference to Fig. 98. In the third example, the amount of information of the position shift amount can be further reduced.

[0578] 98 is a diagram for explaining a third example of the position shift. In the third example, the total shift amount of each of the divided data 6811 to 6814 is expressed by three stages of shift amount.

[0579] As shown in (a) of Fig. 98, the three-dimensional data encoding device calculates the common position shift amount using a bounding box 6820. The method of calculating the common position shift amount is the same as the method described with reference to Fig. 94. At this time, the three-dimensional data encoding device determines a plurality of divided regions 6831-6834 ((b) of Fig. 98) for dividing the point cloud data 6810 into a plurality of divided data 6811-6814 according to the determined plurality of divided regions 6831-6834. The plurality of divided regions 6831-6834 are regions corresponding to the plurality of divided data 6811-6814, respectively. The plurality of divided regions 6831-6834 are also called divided region bounding boxes.

[0580] The three-dimensional data encoding device calculates the direction and distance of the vector indicated by the difference between the minimum point of a bounding box 6820 containing all divided data and the minimum point of each divided area 6831 to 6834, as shown in (b) of Figure 98, as the position shift amount of the divided area.

[0581] 98(c), for each of the plurality of divided data 6811-6814, the three-dimensional data encoding device generates bounding boxes 6821-6824 of a size that includes the divided data 6811-6814, and calculates the minimum point of each of the generated bounding boxes 6821-6824. Then, for each of the plurality of divided data 6811-6814, the three-dimensional data encoding device calculates the direction and distance of a vector indicated by the difference between the minimum point of the bounding box corresponding to the divided data and the minimum point of the corresponding divided area as an individual position shift amount of the divided data.

[0582] The three-dimensional data encoding device stores the common position shift amount, the individual position shift amount for each divided data, and bounding box information indicating the size of the bounding box 6820 in the bit stream.

[0583] The common position shift amount and the first bounding box information indicating the position and size of the minimum point of the bounding box 6820 are stored in the SPS of the data configuration of the bitstream shown in (e) of FIG. 98. The individual position shift amount is stored in the header of the position information of the corresponding divided data. The divided area information including the position shift amount for each divided area is stored in, for example, a parameter set in which the division metadata is stored. The second bounding box information of the bounding boxes 6821-6824 used in encoding each divided data 6811-6814 is stored in the header of the position information of the corresponding divided data. Here, each bounding box 6821-6824 used in encoding each divided data 6811-6814 is included in each divided area 6831-6834.

[0584] Here, if the common position shift amount is Shift_A, the individual position shift amount is Shift_B(i), and the position shift amount of the divided area is Shift_C(i) (i is the index of the divided data), the shift amount Shift(i) of the divided data (i) can be calculated using the following formula.

[0585] Shift(i) = Shift_A + Shift_B(i) + Shift_C(i)

[0586] That is, as shown in (d) of FIG. 98, the total shift amount for each divided data can be calculated by adding up three shift amounts: the common position shift amount, the position shift amount for the divided area, and the individual position shift amount.

[0587] Before encoding the point cloud data, the three-dimensional data encoding device shifts the position of the point cloud data of the i-th divided data by subtracting Shift(i).

[0588] The three-dimensional data decoding device obtains Shift_A, Shift_B(i), and Shift_C(i) from the SPS and the headers of the divided data, calculates Shift(i), and then adds Shift(i) to the decoded divided data(i) to return the divided data to their original positions. This allows multiple divided data to be correctly decoded.

[0589] This method has the effect of reducing the amount of information on the shift amount for each divided data by indicating the individual position shift amount as a difference from the divided area when dividing area information is sent.

[0590] Depending on whether or not divided region information is sent, the individual position shift amount may be switched between the difference between the minimum value point of the common bounding box and the minimum value point of each individual bounding box, or the difference between the minimum value point for each divided region and the minimum value point of each individual bounding box. In the latter case, the individual position shift amount is represented by the sum of the position shift amount of the divided region and the calculated difference.

[0591] Fig. 99 is a flowchart showing an example of an encoding method in which the first example and the third example are switched when performing individual position shifting. Fig. 100 is a flowchart showing an example of a decoding method in which the first example and the third example are switched when performing individual position shifting.

[0592] The three-dimensional data encoding device determines a division method for the point cloud data 6810 (S6821) as shown in Fig. 99. Specifically, the three-dimensional data encoding device determines whether to shift the position of the point cloud data in the first example or in the third example.

[0593] The three-dimensional data encoding device determines whether the determined division method is the third example method using divided regions (S6822).

[0594] If the three-dimensional data encoding device determines that the first example method is used (No in S6822), it sets the individual position shift amount to the difference between the minimum value point of the common BB and the minimum value point of the individual BB (S6823).

[0595] The three-dimensional data encoding device generates a bit stream including the common information and the individual information (S6824). The bit stream may include identification information indicating that the method is the first example.

[0596] If the three-dimensional data encoding device determines that the third example method is being used (Yes in S6822), it sets the individual position shift amount to the difference between the minimum value point of the divided area BB and the minimum value point of the individual BB (S6825).

[0597] The three-dimensional data encoding device transmits a bit stream including the common information, the individual information, and the divided region information (S6826). The bit stream may include identification information indicating that the method is the third example.

[0598] As shown in FIG. 100, the three-dimensional data decoding device acquires a bitstream to determine whether the bitstream includes division region information (S6831). As a result, the three-dimensional data decoding device determines whether the acquired bitstream includes point cloud data encoded in the first example or in the third example. Specifically, if the bitstream includes division region information, the device determines that the bitstream includes point cloud data encoded in the third example, and if the bitstream does not include division region information, the device determines that the bitstream includes point cloud data encoded in the first example. The three-dimensional data decoding device may acquire identification information included in the bitstream to determine whether the bitstream has been encoded in the first example or in the third example.

[0599] If the bitstream does not include split area information (No in S6831), that is, if it is encoded in the first example, the three-dimensional data decoding device obtains common information and individual information from the bitstream (S6832).

[0600] Based on the acquired common information and individual information, the three-dimensional data decoding device calculates the position shift amount for each divided data, i.e., the position shift amount Shift(i), the common BB and the individual BB in the first example, and decodes the point cloud data using this information (S6833).

[0601] If the bitstream contains split area information (Yes in S6831), that is, if it is encoded in the third example, the three-dimensional data decoding device obtains common information, individual information and split area information from the bitstream (S6834).

[0602] Based on the acquired common information, individual information and divided area information, the three-dimensional data decoding device calculates the position shift amount for each divided data, i.e., the position shift amount Shift(i), common BB, individual BB and divided area in the third example, and decodes the point cloud data using this information (S6835).

[0603] Next, a fourth example in which a divided area of ​​a space in which point cloud data exists is shifted by a position shift amount determined as a bounding box for encoding will be described with reference to Fig. 101. In the fourth example, the divided area and each bounding box match, so the amount of information of the bounding box can be reduced compared to the third example.

[0604] 101 is a diagram for explaining a fourth example of the position shift. In the fourth example, the total shift amount of each of the divided data 6811 to 6814 is expressed in two stages of shift amounts, that is, a common position shift amount and a position shift amount of the divided area.

[0605] The three-dimensional data encoding device calculates a common position shift amount using a bounding box 6820, as shown in (a) of Fig. 101. The method of calculating the common position shift amount is the same as the method described with reference to Fig. 94. At this time, the three-dimensional data encoding device divides the point cloud data 6810 into a plurality of divided data 6811 to 6814. The method of dividing the point cloud data 6810 is the same as the method described with reference to (a) of Fig. 98.

[0606] The three-dimensional data encoding device calculates the amount of position shift of the divided region as shown in (b) of Fig. 101. The method of calculating the amount of position shift of the divided region is the same as the method described using (b) of Fig. 98.

[0607] The three-dimensional data encoding device calculates the position shift amount of the divided region as an individual position shift amount of each of the divided data 6811 to 6814. For this reason, the three-dimensional data encoding device stores in the bit stream the common position shift amount, the individual position shift amount (position shift amount of the divided region), and bounding box information indicating the size of the bounding box (divided region).

[0608] Note that the common position shift amount and the first bounding box information indicating the position and size of the minimum point of the bounding box 6820 are stored in the SPS in the data configuration of the bitstream shown in (d) of FIG.

[0609] Moreover, the individual position shift amount is stored in at least one of the header of the position information of the corresponding divided data and the division metadata. When the individual position shift amount is stored in one of the header of the position information and the division metadata, identification information indicating that the individual position shift amount is stored in the header of the position information of the divided data, or identification information indicating that the individual position shift amount is stored in the division metadata may be stored in the GPS or SPS. Alternatively, the individual position shift amount may be stored in, for example, the header of the divided data, and identification information (flag) indicating whether the position shift amount and the bounding box information stored in the header of the divided data match the divided area may be stored in the GPS or SPS. Thereby, the three-dimensional data decoding device can determine that the divided area information is stored in the header of the divided data by the above flag, and use the position shift amount and the bounding box information stored in the header of the divided data as the information of the divided area. Alternatively, the above flag may be stored in the division metadata, and the three-dimensional data decoding device may acquire the divided area information by referring to the header of the divided data when the above flag indicates 1, that is, when the division area information is stored in the header of the divided data.

[0610] Here, if the common position shift amount is Shift_A, the individual position shift amount is Shift_B(i), and the position shift amount of the divided area is Shift_C(i) (i is the index of the divided data), the shift amount Shift(i) of the divided data (i) can be calculated using the following formula.

[0611] Shift_B(i) = Shift_C(i)

[0612] Shift(i) = Shift_A + Shift_B(i)

[0613] That is, as shown in FIG. 101(c), the total shift amount of each divided data can be calculated by adding the common position shift amount and the position shift amount of the divided area (that is, the individual position shift amount).

[0614] Before encoding the point cloud data, the three-dimensional data encoding device shifts the position of the point cloud data of the i-th divided data by subtracting Shift(i).

[0615] The three-dimensional data decoding device obtains Shift_A, Shift_B(i) or Shift_C(i) from the SPS and the header of the divided data, calculates Shift(i), and then adds Shift(i) to the decoded divided data(i) to return the divided data to its original position. This allows multiple divided data to be correctly decoded.

[0616] This method has the effect of reducing the amount of information by making the individual position shift amount the position shift amount of the divided region, and therefore eliminating the need to send new divided region information even when it is necessary to send divided region information.

[0617] Depending on whether or not the divided region information is sent, it may be possible to switch between using the bounding box information of the individual bounding boxes of each divided data or using the divided region information as the individual position shift amount.

[0618] FIG. 102 is a flowchart showing an example of an encoding method in which the third example and the fourth example are switched when storing divided region information.

[0619] The three-dimensional data encoding device determines a division method for the point cloud data 6810 (S6841), as shown in Fig. 102. Specifically, the three-dimensional data encoding device determines whether to shift the position of the point cloud data in the third example or in the fourth example. The three-dimensional data encoding device may make the determination based on the amount of header information reduction or the result of calculating the encoding efficiency.

[0620] The three-dimensional data encoding device determines whether to perform position shifting using individual bounding boxes based on the determined division method (S6842). That is, the three-dimensional data encoding device determines whether to use the method of the third example or the method of the fourth example.

[0621] If the three-dimensional data encoding device determines that the third example method is being used (Yes in S6842), it sets the individual position shift amount to the difference between the minimum value point of the divided area BB and the minimum value point of the individual BB (S6843).

[0622] The three-dimensional data encoding device generates a bit stream including the common information, the individual information, and the divided region information (S6844). The bit stream may include identification information indicating that the method is the third example.

[0623] If the three-dimensional data encoding device determines that the method is the fourth example method (No in S6842), it sets the individual position shift amount to the difference between the minimum value point of the common BB and the minimum value point of the divided area BB (S6845).

[0624] The three-dimensional data encoding device transmits a bit stream including the common information and the divided region information (S6846). The bit stream may include identification information indicating that the method is the fourth example method.

[0625] Next, a fifth example of a position shift by a position shift amount determined using a divided area of ​​a space in which point cloud data exists will be described with reference to Fig. 103. In the fifth example, the amount of information of the shift amount can be reduced.

[0626] 103 is a diagram for explaining a fifth example of the position shift. The fifth example is different from the third example in that the divided regions of the third example are equally divided regions.

[0627] As shown in (a) of FIG. 103, the three-dimensional data encoding device calculates the common position shift amount using a bounding box 6820. The calculation method of the common position shift amount is the same as the method described with reference to FIG. 94. At this time, the three-dimensional data encoding device determines a plurality of divided areas 6841 to 6844 ((b) of FIG. 103) for dividing the point cloud data 6810 into a plurality of areas according to a predetermined rule, for example, based on the bounding box 6820. For example, when the bounding box 6820 is divided into N equal parts and N=4, the three-dimensional data encoding device can generate four divided areas 6841 to 6844 of equal size. Here, for example, when it is determined that the area number is defined in Morton order as an identifier for identifying each of the divided areas 6841 to 6844, the size of each divided area is equal, so that the position shift amount of the divided area can be calculated from the division number of the area and the area number. For this reason, the three-dimensional data encoding device may transmit the division number of the area and identification information for identifying the area instead of transmitting the position shift amount of the divided area. As described above, the identification information is the Morton order corresponding to each of the plurality of divided areas 6841 to 6844.

[0628] The example of (c) in Figure 103 is an example in which the coding area is an individual bounding box for each of a plurality of divided data. In this case, the position shift amount of each divided data is indicated by the sum of the common position shift amount, the position shift amount of the corresponding divided area, and the individual position shift amount from the reference position (the position of the smallest point) of the corresponding divided area. In this case, the corresponding divided area does not have to include the entire coding area (i.e., individual BB).

[0629] The example of (d) in Figure 103 is an example in which the coding area of ​​each divided data is matched with each divided area. In this case, the position shift amount of each divided data is indicated by the sum of the common position shift amount and the position shift amount of the corresponding divided area. In this case, the corresponding divided area is matched with the coding area (i.e., individual BB), so it includes the coding area.

[0630] In this way, the three-dimensional data encoding device may or may not match the encoding area of ​​each divided data with the divided area when dividing the point cloud data. When the encoding area of ​​each divided data is matched with the divided area, either method of (c) in Figure 103 or (d) in Figure 103 can be used. When the encoding area of ​​each divided data is not matched with the divided area, the method of (c) in Figure 103 can be used.

[0631] When the methods of (c) and (d) in Fig. 103 are used, the common position shift amount and bounding box information indicating the position and size of the minimum point of the bounding box 6820 are stored in the SPS of the bitstream data structure. Also, information on the division method and the number of divisions as divided area information are stored in the SPS or GPS as information common to all divided data, and the number (identification information) of each divided area in a predetermined order (Morton order) is stored in the header of the position information of the divided data as information of each divided area.

[0632] Moreover, the individual position shift amount is stored in the header of the position information of the corresponding divided data. In the case of (c) of Fig. 103, the individual position shift amount is further stored in the header of the position information of the divided data.

[0633] When the divided area and the divided data are matched (i.e., when the divided area and the individual bounding box of the divided data are matched), the number of the divided data (tile ID) included in the header of the position information of the divided data may be treated as a number in a predetermined order for each divided area. In this way, by indicating the individual position shift amount by the identification information for each data (a number in a predetermined order), the amount of information in the header can be reduced.

[0634] In addition, when the three-dimensional data encoding device uses the division method of the fifth example, it indicates the position shift amount of the divided area using area information including the number of divisions and identification information of the divided area by using a division method that divides a common bounding box equally and in a predetermined order, and when using a different division method, it may switch to indicating the position shift amount using a method that does not use the above-mentioned area information.

[0635] Here, if the common position shift amount is Shift_A, the individual position shift amount is Shift_B(i), and the position shift amount of the divided area is Shift_D(i) (i is the index of the divided data), the shift amount Shift(i) of the divided data (i) can be calculated using the following formula.

[0636] Shift(i) = Shift_A + Shift_B(i) + Shift_D(i)

[0637] That is, the total shift amount of each divided data can be calculated by adding up three shift amounts: the common position shift amount, the position shift amount of the divided area, and the individual position shift amount.

[0638] Before encoding the point cloud data, the three-dimensional data encoding device shifts the position of the point cloud data of the i-th divided data by subtracting Shift(i).

[0639] The three-dimensional data decoding device obtains Shift_A and Shift_B(i) from the SPS and the header of the divided data, and further obtains information on the division method, the number of divisions, and a number in a predetermined order for each divided area as divided area information, derives the position shift amount Shift_D(i) by a predetermined method, calculates Shift(i), and then adds Shift(i) to the decoded divided data(i) to return the divided data to its original position. This allows multiple divided data to be correctly decoded.

[0640] A specific example of reducing the rules and header amount when dividing point cloud data into octets is described below. Fig. 104 is a diagram for explaining an encoding method when dividing a three-dimensional space into octets.

[0641] First, the three-dimensional data encoding device may divide the point cloud data in the three-dimensional space by an octet tree after offsetting (shifting or moving) the point cloud data by a common position shift amount. The three-dimensional data encoding device divides the bounding box 6850 of the point cloud data into eight divided regions by an octet tree, and sets the number of divisions by the Depth of the octet tree. For example, the number of divisions for Depth is given by N=2^(Depth*3), and the number of divisions is 8 when Depth=1, and 64 when Depth=2. The order of the divided regions is Morton order. The position information of the divided regions can be calculated from the Morton order by applying the fifth example to the three-dimensional space. The Morton order has a feature that it can be calculated from the position information of the divided regions by a predetermined method.

[0642] The bounding box information of the point cloud data is stored in the SPS or GPS, which contains metadata common to multiple divided data. The bounding box information includes the minimum point (initial position) and size of the bounding box.

[0643] The three-dimensional data encoding device stores identification information indicating that the division method is an octet tree, and, if the division method is an octet tree division, depth information indicating the depth of the octet tree in the SPS or GPS of the data structure of the bit stream shown in (e) of Fig. 104. The header of each divided data stores a number in Morton order as the divided data number. Furthermore, if the division method is an octet tree, the position shift amount of the divided data and the encoding bounding box information are assumed to be derived from Morton order, and are not stored in the bit stream.

[0644] That is, as shown in (f) of Fig. 104, the three-dimensional data encoding device calculates identification information indicating that the data has been divided into an octet tree, the depth of the octet tree, and the Morton order using a predetermined method for the position information of each of the multiple divided areas divided into an octet tree. As shown in (g) of Fig. 104, the three-dimensional data decoding device obtains the identification information indicating that the data has been divided into an octet tree, the depth of the octet tree, and the Morton order, and restores the position information of each of the multiple divided areas divided into an octet tree using a predetermined method.

[0645] If there is no point cloud data in a divided area, the divided area information may not be necessary. For example, if there is no point cloud data in an area with divided data number = 2, the divided data number is not sent, so the sequence of divided data numbers skips 2 and becomes 1, 3, 4.

[0646] The division metadata may store a division data number, or may store all division area information including division areas that do not have point cloud data. In this case, the division area information may indicate whether or not the division area has point cloud data.

[0647] FIG. 105 is a diagram showing an example of GPS syntax.

[0648] The octree_partition_flag is a flag indicating whether the point cloud data is divided by octree partitioning.

[0649] Depth indicates the depth of the octree division when dividing point cloud data into octrees.

[0650] gheader_BBmin_present_flag is a flag indicating whether or not the position information field of the bounding box of the encoded point cloud data is present in the header of the position information.

[0651] gheader_BBsize_present_flag is a flag indicating whether or not the size information field of the bounding box of the encoded point cloud data is present in the header of the position information.

[0652] When octree_partition_flag=1, gheader_BBmin_present_flag and gheader_BBsize_present_flag are set to 0.

[0653] FIG. 106 is a diagram illustrating an example of the syntax of the header of the location information.

[0654] The partition_id indicates identification information of the divided data. In the case of octree division, the partition_id indicates a unique position in the order of the Morton order.

[0655] BBmin indicates the amount of shift when encoding data or divided data.

[0656] BBsize indicates the size of the bounding box when encoding the data or divided data.

[0657] Although the division of the octet tree has been described as an example, this method can be applied to other division methods by determining a predetermined division method, the order of the divided data, and the calculation method of the position information. For example, when the point cloud data is viewed from above and divided at equal intervals on the xy plane, the division method is the above division method, and the number of divisions or the size of the divisions and the order are determined and transmitted, so that both the three-dimensional data encoding device and the three-dimensional data decoding device can calculate the position information and the position shift amount based on the information. By not transmitting the position information, the amount of data can be reduced. It is also possible to transmit information on the plane to be divided, or information on the division to be made by quadtree.

[0658] Fig. 107 is a flowchart showing an example of an encoding method in which processing is switched depending on whether or not octree division is performed. Fig. 108 is a flowchart showing an example of a decoding method in which processing is switched depending on whether or not octree division is performed.

[0659] The three-dimensional data encoding device determines a division method for the point cloud data (S6851), as shown in FIG.

[0660] The three-dimensional data encoding device determines whether or not to perform octree division based on the determined division method (S6852).

[0661] If the three-dimensional data encoding device determines not to perform octree division (No in S6852), it determines the individual position shift amount to be the minimum point of the individual BB for each divided data, shifts the position of the divided data, and encodes the divided data using the individual BB (S6853).

[0662] The three-dimensional data encoding device stores information about the common BB in the common metadata (S6854).

[0663] The three-dimensional data encoding device stores the individual position shift amount for each divided data in the header of the divided data (S6855).

[0664] If the three-dimensional data encoding device determines that octree division is to be performed (Yes in S6852), it determines the individual position shift amount to be the minimum point of the octree divided divided area, shifts the position of the divided data, and encodes the divided data using the octree divided area (S6856).

[0665] The three-dimensional data encoding device stores the common BB information, identification information indicating that the octree division has been performed, and the depth information in the common metadata (S6857).

[0666] The three-dimensional data encoding device stores, in the header of the divided data, sequence information indicating the order of the Morton order for identifying the individual position shift amount for each divided data (S6858).

[0667] The three-dimensional data decoding device acquires information indicating a method for dividing the point cloud data from the common metadata (S6861).

[0668] The three-dimensional data decoding device determines whether the division method is octree division or not based on the acquired information indicating the division method (S6862). Specifically, the three-dimensional data decoding device determines whether the division method is octree or not based on the identification information indicating whether octree division has been performed or not.

[0669] If the division method is not octree division (No in S6862), the three-dimensional data decoding device acquires the common BB information, the individual position shift amount, and the individual BB information, and decodes the point cloud data (S6863).

[0670] If the division method is octree division (Yes in S6862), the three-dimensional data decoding device obtains common BB information, depth information and individual order information, calculates individual position shift amounts and encoded BB information, and decodes the point cloud data (S6864).

[0671] It is expected that the amount of code can be reduced by using any of the methods of the examples described in this embodiment. A predetermined method may be used to switch to any of the methods of the examples.

[0672] For example, the three-dimensional data encoding device may calculate the code amount and determine to perform the first method among the above-mentioned multiple methods under a predetermined condition according to the calculated code amount. Alternatively, in the case of lossy compression, if the quantization coefficient is larger than a predetermined value, if the number of divisions of the data is larger than a predetermined number, or if the number of point groups is smaller than a predetermined number, the device may switch from the first method to the second method among the above-mentioned multiple methods if there is a possibility that the overhead will change.

[0673] In addition, although the header of each split data stores the difference with respect to the common information as individual information corresponding to the split data, this is not limited to the above, and the difference between the split data and the individual information of the split data immediately preceding the split data may be stored as individual information of the split data.

[0674] Fig. 109 is a diagram showing an example of the data structure of a bit stream when divided data is classified into randomly accessible data A and non-randomly accessible data B. Fig. 110 shows an example when the divided data of Fig. 109 is classified into frames.

[0675] In this case, that is, when there are one or more random access units, different information may be stored in the data header of the A data and the data header of the B data. For example, the divided data of the A data may store individual difference information from the common information stored in the GPS, and the divided data of the B data may store difference information from the A data in the random access unit. Note that, when multiple divided data of the B data are included in the random access unit, each of the multiple divided data of the B data included in the same random access unit may store difference information from the A data, and the multiple divided data of the B data may store difference information from the A data or B data immediately before the B data.

[0676] Although the above describes divided data, the same applies to frames.

[0677] In this embodiment, the division areas or division boundaries in data division have been mainly described using an example (Figure 111) in which the BBs of all divided data are targeted and the area is divided, but even if the division area is other than this, the same effect of reducing the amount of code can be expected by using the method of this embodiment.

[0678] When dividing a BB including all divided data as shown in Fig. 111, the three-dimensional data encoding device may shift the position of the BB based on the minimum value, and may treat the point cloud data after the position shift as the division target. In addition, when the point cloud data is scaled or quantized, the three-dimensional data encoding device may treat the point cloud data after the scaling or quantization as the division target, or may treat the point cloud data before the scaling or quantization as the division target.

[0679] As shown in Fig. 112, the three-dimensional data encoding device may set the divided regions in the coordinate system of the input data of the point cloud data. In this case, the three-dimensional data encoding device does not shift the point of the minimum value of BB of the point cloud data.

[0680] As shown in Fig. 113, the three-dimensional data encoding device may set the divided regions in a coordinate system higher than the point cloud data. For example, the three-dimensional data encoding device may set the divided regions based on GPS coordinates of map data or the like.

[0681] In this case, the three-dimensional data encoding device may store relative position information of the coordinate system of the point cloud with respect to the higher-level coordinate system in the bit stream and transmit it. For example, when a sensor such as an in-vehicle Lidar senses point cloud data while moving, the three-dimensional data encoding device may transmit the position information of the sensor (GPS coordinates, acceleration, speed, and moving distance) as relative position information. In addition, in the case of point cloud data having a time-series frame structure, the three-dimensional data encoding device may store time-series sensor position information for each frame in the bit stream and transmit it. Note that the higher-level coordinate system may be absolute coordinates or relative coordinates based on absolute coordinates. The higher-level coordinate system may be a coordinate system even higher than the higher-level coordinate system.

[0682] As shown in FIG. 114, the three-dimensional data encoding device may determine the divided regions based on the object or data attributes of the point cloud data. For example, the three-dimensional data encoding device may determine the divided regions based on the image recognition result. In this case, the divided regions may include overlapping regions. The three-dimensional data encoding device may cluster each point of the point cloud based on a predetermined attribute, may divide the data based on the number of points, or may divide the region so as to have an approximately equal number of point clouds.

[0683] The three-dimensional data encoding device may signal the number of points to be encoded, and the three-dimensional data decoding device may use the number of points to decode the point cloud data.

[0684] The encoding target is set for each frame or for each divided data obtained by dividing one frame, and the number of points to be encoded is basically stored in each data header. The number of points to be encoded that is signaled may be stored as a reference value in common metadata, and information on the difference from the reference value may be stored in the data header.

[0685] For example, as shown in Fig. 115, the three-dimensional data encoding device may store a reference number of points A (i.e., a reference value) in the GPS or SPS, and store the number of points B(i) (i is the index of the divided data), which is the difference from the reference number of points A, in each data header. The number of points in divided data (i) is obtained by adding the number A to the number B(i). Therefore, the three-dimensional data decoding device calculates A+B(i) and decodes the calculated value as the number of points in divided data (i).

[0686] Alternatively, as shown in Fig. 116, the three-dimensional data encoding device may store, in each data header, difference information from the number of points of the previous divided data of the divided data. In this case, the number of points of divided data (i) is obtained by adding the numbers B(1) to B(i) of the first divided data to the number A.

[0687] Also, for example, in the case of time-series point group data having a multiple frame structure as shown in Fig. 117, the three-dimensional data encoding device may store a reference value for the number of points to be encoded in a common SPS, and store the relative value of each frame with respect to the reference value in the GPS or data header. The three-dimensional data encoding device may also store in the GPS the difference (relative value) with respect to the reference value stored in the SPS, and further store in the data header the difference (relative value) from the sum of the reference value of the SPS and the difference value of the GPS. This is expected to reduce the overhead coding amount.

[0688] As a method for dividing the point cloud data, a method for dividing the data so that the number of points is approximately equal can be considered. In that case, the same method as in FIG. 115 can be used.

[0689] For example, as shown in FIG. 118, in a method of dividing data so that the difference between the points contained in the divided data is within 1, Δ may be represented by 1-bit data, and if Δ=0, the difference information does not need to be represented.

[0690] For example, as shown in Fig. 119, the data may be basically composed of data with the reference value recorded in the GPS as the division number and the remainder number. When Δ=0, the difference information does not need to be indicated.

[0691] Whichever method shown in FIGS. 115 to 119 is used, it is possible to expect a reduction in the amount of overhead information.

[0692] As described above, the three-dimensional data encoding device according to the present embodiment performs the process shown in FIG. 120. The three-dimensional data encoding device is a device that encodes point cloud data indicating a plurality of three-dimensional positions in a three-dimensional space. The three-dimensional data encoding device moves the point cloud data by a first movement amount (S6871). Next, the three-dimensional data encoding device divides the three-dimensional space into a plurality of sub-spaces to divide the point cloud data into a plurality of sub-point cloud data (S6872). The three-dimensional data encoding device moves each of a plurality of sub-point cloud data included in the point cloud data after moving by the first movement amount by a second movement amount based on the position of the sub-space in which the sub-point cloud data is included (S6873). The three-dimensional data encoding device generates a bit stream by encoding the plurality of sub-point cloud data after the movement (S6874). The bit stream includes first movement information for calculating the first movement amount and a plurality of second movement information for calculating a plurality of second movement amounts by which the plurality of sub-point cloud data are moved. According to this, since the divided sub-point cloud data is moved and then encoded, the amount of information of the position information of each sub-point cloud data can be reduced, and encoding efficiency can be improved.

[0693] For example, the multiple subspaces have equal sizes. Each of the multiple second movement information includes the number of the multiple subspaces and first identification information for identifying the corresponding subspace. Therefore, the amount of information of the second movement information can be reduced, and the encoding efficiency can be improved.

[0694] For example, the first identification information is a Morton order corresponding to each of the multiple subspaces.

[0695] For example, each of the subspaces is a space obtained by dividing one three-dimensional space using an octet tree. The bit stream includes second identification information indicating that the subspaces are spaces divided using an octet tree and depth information indicating the depth of the octet tree. Therefore, since the point cloud data in the three-dimensional space is divided using an octet tree, the amount of information of the position information of each subpoint cloud data can be reduced, and the coding efficiency can be improved.

[0696] For example, the division is performed after the point cloud data is moved by a first movement amount.

[0697] For example, the three-dimensional data encoding device includes a processor and a memory, and the processor uses the memory to perform the above-mentioned processing.

[0698] Moreover, the three-dimensional data decoding device according to this embodiment performs the process shown in FIG. 121. The three-dimensional data decoding device decodes from the bit stream a plurality of sub-point cloud data, each of which is a set of sub-point cloud data obtained by dividing a three-dimensional space into a plurality of subspaces and which has been moved by a first movement amount and a corresponding second movement amount, a first movement information for calculating the first movement amount, and a plurality of second movement information for calculating a plurality of second movement amounts by which the plurality of sub-point cloud data has been moved (S6881). The three-dimensional data decoding device restores the point cloud data by moving each of the plurality of sub-point cloud data by a movement amount obtained by adding the first movement amount and the corresponding second movement amount (S6882). This allows the point cloud data to be correctly decoded using a bit stream with improved coding efficiency.

[0699] For example, the multiple subspaces have equal sizes. Each of the multiple second movement information includes the number of the multiple subspaces and first identification information for identifying the corresponding subspace. Therefore, the amount of information of the second movement information can be reduced, and the encoding efficiency can be improved.

[0700] For example, the first identification information is a Morton order corresponding to each of the multiple subspaces.

[0701] For example, each of the subspaces is a space obtained by dividing one three-dimensional space using an octet tree. The bit stream includes second identification information indicating that the subspaces are spaces divided using an octet tree and depth information indicating the depth of the octet tree. Therefore, since the point cloud data in the three-dimensional space is divided using an octet tree, the amount of information of the position information of each subpoint cloud data can be reduced, and the coding efficiency can be improved.

[0702] For example, the three-dimensional data decoding device includes a processor and a memory, and the processor uses the memory to perform the above-mentioned processing.

[0703] Although the three-dimensional data encoding device and the three-dimensional data decoding device according to the embodiments of the present disclosure have been described above, the present disclosure is not limited to these embodiments.

[0704] Furthermore, each processing unit included in the three-dimensional data encoding device and the three-dimensional data decoding device according to the above-mentioned embodiments is typically realized as an LSI, which is an integrated circuit. These may be individually implemented as single chips, or some or all of them may be included in a single chip.

[0705] The integrated circuit is not limited to an LSI, but may be realized by a dedicated circuit or a general-purpose processor. A field programmable gate array (FPGA) that can be programmed after the LSI is manufactured, or a reconfigurable processor that can reconfigure the connections and settings of the circuit cells inside the LSI may also be used.

[0706] In each of the above embodiments, each component may be implemented by dedicated hardware or by executing a software program suitable for each component. Each component may be implemented by a program execution unit such as a CPU or processor reading and executing a software program recorded on a recording medium such as a hard disk or semiconductor memory.

[0707] Furthermore, the present disclosure may be realized as a three-dimensional data encoding method or a three-dimensional data decoding method executed by a three-dimensional data encoding device, a three-dimensional data decoding device, or the like.

[0708] In addition, the division of functional blocks in the block diagram is an example, and multiple functional blocks may be realized as one functional block, one functional block may be divided into multiple blocks, or some functions may be transferred to another functional block. Furthermore, the functions of multiple functional blocks having similar functions may be processed in parallel or in a time-sharing manner by a single piece of hardware or software.

[0709] In addition, the order in which each step is performed in the flowchart is merely an example for specifically explaining the present disclosure, and an order other than the above may be used. In addition, some of the steps may be performed simultaneously (in parallel) with other steps.

[0710] Although the three-dimensional data encoding device and the three-dimensional data decoding device according to one or more aspects have been described based on the embodiments, the present disclosure is not limited to these embodiments. As long as it does not deviate from the spirit of the present disclosure, various modifications conceived by a person skilled in the art to the present embodiment and forms constructed by combining components in different embodiments may also be included within the scope of one or more aspects. [Industrial Applicability]

[0711] The present disclosure is applicable to a three-dimensional data encoding device and a three-dimensional data decoding device. [Explanation of symbols]

[0712] 2400 3D data encoding device 2401 Quantization section 2402, 2411 8-ary tree generation part 2403 Merge Decision Unit 2404 Entropy coding unit 2410 Three-dimensional data decoding device 2412 Merge information decoding unit 2413 Entropy Decoding Unit 2414 Inverse quantization section 4601 Three-dimensional data encoding system 4602 Three-dimensional data decoding system 4603 Sensor terminal 4604 External connection part 4611 Point Cloud Data Generation System 4612 Presentation section 4613 Encoding section 4614 Multiplexer 4615 Input / output section 4616 Control Unit 4617 Sensor information acquisition unit 4618 Point Cloud Data Generation Unit 4621 Sensor Information Acquisition Unit 4622 Input / output section 4623 Demultiplexer 4624 Decoding section 4625 Presentation section 4626 User Interface 4627 Control Unit 4630 First Encoding Section 4631 Location information encoder 4632 Attribute information encoder 4633 Additional Information Encoding Unit 4634 Multiplexer 4640 First Decoding Unit 4641 Demultiplexer 4642 Location Information Decoding Unit 4643 Attribute Information Decoding Unit 4644 Additional Information Decoding Unit 4650 Second Encoding Section 4651 Additional Information Generation Unit 4652 Position image generation unit 4653 Attribute Image Generation Unit 4654 Video Encoding Unit 4655 Additional Information Encoding Unit 4656 Multiplexer 4660 Second Decryption Unit 4661 Demultiplexer 4662 Video Decoding Unit 4663 Additional Information Decoding Unit 4664 Location information generator 4665 Attribute information generation section 4670 Encoding section 4680 Decoding section 4710 First Multiplexing Unit 4711 File Conversion Department 4720 First Demultiplexer 4721 File Reverse Conversion Unit 4730 Second Multiplexing Unit 4731 File Conversion Department 4740 Second Demultiplexer 4741 File Reverse Conversion Unit 4750 Third Multiplexer 4751 File Conversion Department 4760 3rd Demultiplexer 4761 File Reverse Conversion Unit 4801 Encoding section 4802 Multiplexer 5010 First encoding unit 5011 Split section 5012 Location information encoder 5013 Attribute information encoder 5014 Additional information coding unit 5015 Multiplexer 5020 First Decryption Unit 5021 Demultiplexer 5022 Location information decoding unit 5023 Attribute Information Decoding Unit 5024 Additional information decoding unit 5025 Joint 5031 Tile division section 5032 Position information slice division part 5033 Attribute Information Slice Division Unit 5041 Position information slice combination part 5042 Attribute information slice combination part 5043 Tile joint 5051 Tile division section 5052 Encoding section 5053 Decryption Unit 5054 Tile joint 6800 3D data encoding device 6801 Division method determination section 6802 Split section 6803a, 6803b quantization section 6804a, 6804b Shift amount calculation unit 6805a, 6805b Common position shift part 6806a, 6806b Individual position shifting parts 6807a, 6807b encoding section

Claims

1. A three-dimensional data encoding method for encoding point cloud data indicating a plurality of three-dimensional positions in a three-dimensional space, comprising the steps of: Dividing the three-dimensional space into a plurality of subspaces to divide the point cloud data into a plurality of sub-point cloud data; Calculating a common movement amount for the plurality of sub-point cloud data, the common movement amount being a movement of the same distance between the plurality of sub-point cloud data and indicating a movement in a direction toward a predetermined point in the three-dimensional space; The plurality of sub-point cloud data are moved by the common movement amount; calculating a plurality of individual movement amounts corresponding to the plurality of sub-point cloud data moved by the common movement amount, the plurality of individual movement amounts being movements of different distances between the plurality of sub-point cloud data moved by the common movement amount and indicating movements in a direction toward the predetermined point; For each of the plurality of sub-point cloud data moved by the common movement amount, move the sub-point cloud data by an individual movement amount corresponding to the sub-point cloud data; Encoding the plurality of sub-point cloud data each moved by a corresponding individual movement amount. Three-dimensional data encoding method.

2. The sub-spaces have equal sizes.

2. The three-dimensional data encoding method according to claim 1.

3. Each of the plurality of subspaces is a space obtained by dividing one three-dimensional space using an octree.

3. The three-dimensional data encoding method according to claim 1 or 2.

4. In the calculation of the common movement amount, Generate a first bounding box that is a rectangular area having a size that can accommodate all of the sub-point cloud data and that is a minimum size that surrounds all of the sub-point cloud data; calculating a first minimum point of the first bounding box that is closest to the predetermined point; The distance between the first minimum point and the predetermined point is calculated as the common movement amount. The three-dimensional data encoding method according to any one of claims 1 to 3.

5. In the calculation of the individual movement amount, generating a plurality of second bounding boxes, each of which has a size sufficient to accommodate one corresponding piece of sub-point cloud data among the plurality of sub-point cloud data moved by the common movement amount, and which is a rectangular region of a minimum size that surrounds the one corresponding piece of sub-point cloud data moved by the common movement amount; Calculating a second minimum point for each of the second bounding boxes, the second minimum point being a point in the second bounding box closest to the predetermined point; For each of the plurality of sub-point cloud data, a distance between a second minimum point of a second bounding box corresponding to the sub-point cloud data and the predetermined point is calculated as an individual movement amount corresponding to the sub-point cloud data. The three-dimensional data encoding method according to any one of claims 1 to 4.

6. a plurality of sub-point cloud data obtained by dividing a three-dimensional space into a plurality of subspaces into which point cloud data indicating a plurality of three-dimensional positions is divided, each of the plurality of sub-point cloud data being moved by a common movement amount and a corresponding individual movement amount, common movement information for calculating the common movement amount, and a plurality of individual movement information for calculating each of the plurality of individual movement amounts by which the plurality of sub-point cloud data has been moved, are decoded from a bit stream, the common movement amount being a movement of the same distance between the plurality of sub-point cloud data and indicating a movement in a direction toward a predetermined point in the three-dimensional space, and the plurality of individual movement amounts by which the plurality of sub-point cloud data has been moved being a movement of different distances between the plurality of sub-point cloud data moved by the common movement amount and indicating a movement in a direction toward the predetermined point; For each of the plurality of sub-point cloud data, the sub-point cloud data is moved by an amount obtained by adding the common amount of movement and the individual amount of movement corresponding to the sub-point cloud data, thereby restoring the point cloud data. A method for decoding three-dimensional data.

7. The sub-spaces have equal sizes, Each of the plurality of pieces of individual movement information includes the number of the plurality of subspaces and first identification information for identifying the corresponding subspace. The three-dimensional data decoding method according to claim 6.

8. The first identification information is a Morton order corresponding to each of the plurality of subspaces. The three-dimensional data decoding method according to claim 7.

9. each of the plurality of subspaces is a space obtained by dividing one three-dimensional space using an octree; The bit stream includes second identification information indicating that the plurality of subspaces are spaces divided using an octree, and depth information indicating a depth of the octree. The three-dimensional data decoding method according to any one of claims 6 to 8.

10. The common movement amount is Generate a first bounding box that is a rectangular area having a size that can accommodate all of the sub-point cloud data and that is a minimum size that surrounds all of the sub-point cloud data; calculating a first minimum point of the first bounding box that is closest to the predetermined point; The distance between the first minimum point and the predetermined point is calculated as the common movement amount. It is calculated by The three-dimensional data decoding method according to any one of claims 6 to 9.

11. The individual movement amount is generating a plurality of second bounding boxes, each of which has a size sufficient to accommodate one corresponding piece of sub-point cloud data among the plurality of sub-point cloud data moved by the common movement amount, and which is a rectangular region of a minimum size that surrounds the one corresponding piece of sub-point cloud data moved by the common movement amount; calculating, for each of the second bounding boxes, a second minimum point that is a point in the second bounding box that is closest to the predetermined point; For each of the plurality of sub-point cloud data, a distance between a second minimum point of a second bounding box corresponding to the sub-point cloud data and the predetermined point is calculated as an individual movement amount corresponding to the sub-point cloud data. It is calculated by The three-dimensional data decoding method according to any one of claims 6 to 10.

12. A program for causing a computer to execute the three-dimensional data encoding method according to any one of claims 1 to 5.

13. A program for causing a computer to execute the three-dimensional data decoding method according to any one of claims 6 to 11.

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