Point group display system, point group display device, point group display method, and point group display program

Abstract

To obtain a point group display system that can resolve the local display of a point group when thinning the point group for display.SOLUTION: A point group display system 1A has a server 20A that stores three-dimensional point group data of a measurement object obtained by measuring the measurement object, and a client terminal 10 that displays the three-dimensional point group. The server 20A comprises a point group processing part 200A that registers the three-dimensional point group data in an eight-subtree structure and determines which node in the eight-subtree structure to use as the three-dimensional point group for the display object based on the display priority in displaying the three-dimensional point group. The point group processing part 200A determines the display object's three-dimensional point group by assigning a shallower node to a display area with lower display priority, thereby increasing the thinning-out rate of the three-dimensional point group for display areas with lower display priority. The client terminal 10 displays the three-dimensional point group with a higher thinning-out rate for display areas with lower display priority.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a point cloud display system, a point cloud display device, a point cloud display method, and a point cloud display program for displaying point cloud data.

Background Art

[0002] One of the technologies for measuring and displaying a three-dimensional shape is a technology that acquires point cloud data indicating three-dimensional coordinates of a three-dimensional shape using a three-dimensional sensor and displays the three-dimensional shape as a point cloud. In a point cloud display system that acquires point cloud data and displays a point cloud, when displaying a point cloud using a Web application, it may be necessary to limit the number of displayed points due to the upper limit of the memory of the browser or the like.

[0003] The data transmission device described in Patent Document 1 reduces the point cloud data in a specific region for the point cloud data including three-dimensional coordinates, transfers it to a remote operation terminal, and displays the reduced point cloud data on a display device.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the technology of Patent Document 1 described above, for high-density point cloud display, only the point cloud near the fixation point is displayed, and the point cloud in the region far from the fixation point is not displayed, and there is a problem that the point cloud can be displayed only locally.

[0006] The present disclosure has been made in view of the above, and an object thereof is to obtain a point cloud display system capable of eliminating local display of a point cloud when subsampling and displaying the point cloud.

Means for Solving the Problems

[0007] In order to solve the above-described problems and achieve the object, the point cloud display system of the present disclosure includes a server that stores three-dimensional point cloud data of a measurement target obtained by measuring the measurement target, and a point cloud display device that displays a three-dimensional point cloud corresponding to the three-dimensional point cloud data. The server registers the three-dimensional point cloud data in an octree structure, and includes a point cloud processing unit that determines which node among the nodes of the octree structure is to be the three-dimensional point cloud to be displayed based on the display priority when displaying the three-dimensional point cloud. The point cloud processing unit determines that the shallower the node in the display area with a lower display priority, the higher the decimation rate of the three-dimensional point cloud, and the three-dimensional point cloud with a higher decimation rate in the display area with a lower display priority is displayed.

Effect of the Invention

[0008] The point cloud display system according to the present disclosure has an effect that it can eliminate the local display of the point cloud when thinning and displaying the point cloud.

Brief Description of the Drawings

[0009]

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Embodiments for Carrying Out the Invention

[0010] Hereinafter, the point cloud display system, point cloud display device, point cloud display method, and point cloud display program according to the embodiments of the present disclosure will be described in detail with reference to the drawings

[0011] Embodiment 1. FIG. 1 is a diagram showing the configuration of the point cloud display system according to Embodiment 1. The point cloud display system 1A is a system that displays a three-dimensional shape as a point cloud using three-dimensional point cloud data (hereinafter referred to as point cloud data) indicating the three-dimensional coordinates of the three-dimensional shape measured using a three-dimensional sensor.

[0012] The point cloud display system 1A according to Embodiment 1 eliminates the local display of the point cloud when subsampling the point cloud by changing the display priority of the point cloud used for point cloud display according to the distance from the fixation point set by the user. The fixation point in Embodiment 1 is a position (coordinates (X, Y, Z) in three-dimensional space) that the user wants to fix and view with respect to the three-dimensional space, and can be arbitrarily changed by the user. Note that the viewpoint described later can also be arbitrarily changed by the user.

[0013] The point cloud display system 1A includes a client terminal 10, which is a point cloud display device, and a server 20A. The server 20A, which is a computer, stores the point cloud data of the measurement target obtained by measuring the measurement target, and transmits the requested point cloud data to the client terminal 10 from the client terminal 10. The client terminal 10, which is a computer, displays the point cloud corresponding to the point cloud data acquired from the server 20A.

[0014] The server 20A according to Embodiment 1 generates an octree structure with upsampling for the point cloud data requested from the client terminal 10. The octree structure is a data structure (tree structure) that represents the division of point cloud data (set of points) in three-dimensional space. Hereinafter, the octree structure is referred to as an octree. Also, an octree with upsampling is referred to as an upsampled octree.

[0015] Here, the "octree" and "uploading" will be described. When there are a specified number of points or more in the three-dimensional space where the point cloud is arranged, the server 20A divides the space into eight parts by equally dividing the space vertically, horizontally, and front-to-back. As a result, the parent node (root), which is the original divided space, corresponds to the entire three-dimensional space, and the eight child nodes, which are the spaces after division, correspond to the space equally divided into eight parts by being bisected by planes perpendicular to the X-axis, Y-axis, and Z-axis respectively.

[0016] Similarly, for each space thus divided into eight parts, if the division conditions are met, the server 20A divides it into eight parts again to set up finer spaces. The server 20A generates an octree by repeatedly dividing the three-dimensional space into eight parts until there are no more spaces that meet the division conditions. In this way, the server 20A recursively divides the three-dimensional space into eight spaces. As a result, in the octree, a maximum of eight child nodes are set for each parent node.

[0017] Also, "uploading" means storing a certain proportion (for example, one-eighth) of the points that the child nodes have in the parent node. Note that the uploading ratio can be arbitrarily set by the user of the point cloud display system 1A.

[0018] The server 20A uploads the points that the child nodes have to the parent node by setting and managing a certain proportion of the number of points in the data of the points included in the child nodes (such as coordinates in the three-dimensional space) in the parent node. The server 20A manages the point data in all nodes by uploading the point cloud data of the child nodes to the parent node.

[0019] The point cloud display system 1A of Embodiment 1 manages the information of the point cloud data for all nodes by generating an uploading octree. In a normal octree, however, the information of the point cloud data is managed only for the terminal nodes.

[0020] The server 20A of Embodiment 1 decimates the point cloud data managed using a quadtree so that the number of point clouds to be displayed on the screen is equal to or less than the set number. Specifically, the server 20A increases the display priority of the point cloud display for regions (positions) closer to the fixation point, and makes the nodes used for display deeper for regions with higher display priority. In a quadtree, deeper nodes contain a larger number of point cloud data, and the point cloud data is decimated by aggregation as the nodes become shallower. Therefore, the client terminal 10 can perform a point cloud display with a higher density for regions closer to the fixation point. As a result, even at positions far from the fixation point, the point cloud data is displayed at a lower density than near the fixation point, eliminating the problem that only the area near the fixation point is displayed as a point cloud.

[0021] The set number of point clouds to be displayed on the screen is set based on, for example, the upper limit of the memory of the display browser, which is a web application. For example, if the upper limit of the memory of the point cloud display browser is 1GB, 3 million points of point cloud display can be displayed with a margin, so 3 million points are set as the set number of point clouds to be displayed on the screen.

[0022] The client terminal 10 includes a screen operation unit 11, a point cloud selection unit 12, a screen display unit 13 as a display unit, and a display information generation unit 14. The server 20A includes a point cloud DB (Database) 21, a point cloud registration unit 22A, and a point cloud management unit 23A. The point cloud registration unit 22A and the point cloud management unit 23A are a point cloud processing unit 200A that registers the point cloud data obtained by measuring the measurement target using a quadtree.

[0023] The point cloud DB21 is a storage unit that stores point cloud data of a three-dimensional space obtained by measuring a measurement target. This point cloud data is data measured for each three-dimensional space using a three-dimensional sensor. The point cloud data includes information on three-dimensional coordinates in the three-dimensional space. The three-dimensional shape represented by the point cloud data can be displayed as the shape seen from the position of the viewpoint when the position of the viewpoint is set. The viewpoint in Embodiment 1 is a position (coordinates (X, Y, Z) in the three-dimensional space) indicating from where the user wants to view the three-dimensional space, and can be arbitrarily changed by the user.

[0024] The screen operation unit 11 receives operations executed by the user. The screen operation unit 11 receives information (point cloud data specification information) specifying point cloud data from the user. The user specifies the point cloud data to be displayed by specifying information (such as a file name) for identifying the point cloud data.

[0025] In addition, the screen operation unit 11 receives an instruction (fixation point setting instruction) to set the coordinates of the fixation point and an instruction (viewpoint setting instruction) to set the coordinates of the viewpoint from the user. The user may set the coordinates of the fixation point and the coordinates of the viewpoint while viewing the image of the displayed point cloud, or may set the coordinates of the fixation point and the coordinates of the viewpoint while viewing the distribution range information described later indicating the distribution of the point cloud.

[0026] The screen operation unit 11 transmits the point cloud data specification information received from the user to the point cloud selection unit 12 and the display information generation unit 14. In addition, the screen operation unit 11 transmits the fixation point setting instruction and the viewpoint setting instruction received from the user to the point cloud selection unit 12.

[0027] The point cloud selection unit 12 transmits the point cloud data specification information to the point cloud registration unit 22A. In addition, the point cloud selection unit 12 derives the display range of the point cloud based on the fixation point setting instruction and the viewpoint setting instruction. The point cloud selection unit 12 transmits the display range of the point cloud, the fixation point setting instruction, and the viewpoint setting instruction to the display information generation unit 14 as display specification information. This display specification information is transmitted from the display information generation unit 14 to the point cloud management unit 23A.

[0028] The point cloud registration unit 22A reads out the point cloud data corresponding to the point cloud data specification information from the point cloud DB 21. Hereinafter, the point cloud data read out by the point cloud registration unit 22A from the point cloud DB 21 as specified by the user may be referred to as the specified point cloud.

[0029] The point cloud registration unit 22A generates an uploaded octree which is an uploaded octree with uploads for the specified point cloud. The point cloud registration unit 22A registers the generated uploaded octree and the specified point cloud in the point cloud management unit 23A.

[0030] The point cloud management unit 23A selects the data (coordinate values, etc.) of the point cloud to be used for display from the specified point cloud based on the uploaded octree and the display specification information. That is, the point cloud management unit 23A identifies the nodes including the point cloud to be displayed based on the uploaded octree and the display specification information, and selects the data of the point cloud included in the identified nodes. Note that the point cloud management unit 23A may receive a fixation point setting instruction and a viewpoint setting instruction from the display information generation unit 14, and identify the display range based on the fixation point setting instruction and the viewpoint setting instruction.

[0031] The point cloud management unit 23A stores the selected point cloud data as the display point cloud data. The display point cloud data generated by the point cloud management unit 23A includes distribution range information which is the range of the distribution of the point cloud included in the specified point cloud (coordinate range).

[0032] The point cloud management unit 23A sets the display priority according to the distance from the fixation point for each display area in the image so that the number of point clouds to be displayed is equal to or less than the set number. The point cloud management unit 23A sets a higher display priority for the display area closer to the fixation point so that a larger number of point clouds are displayed in the display area closer to the fixation point. The point cloud management unit 23A sets the point cloud data of deeper nodes for the display area with a higher display priority.

[0033] The point cloud management unit 23A stores the point cloud data set for each display area corresponding to the three-dimensional space. When the point cloud management unit 23A receives further display specification information after acquiring the display point cloud data, it changes the coordinates of the fixation point, the coordinates of the viewpoint, and the display range. In this case, the point cloud management unit 23A stores the display point cloud data with the changed coordinates of the fixation point, the coordinates of the viewpoint, and the display range. The point cloud management unit 23A has a memory or the like for storing the display point cloud data.

[0034] The display information generation unit 14 reads out the distribution range information from the point cloud management unit 23 and causes the screen display unit 13 to display it. As a result, the user can set a desired fixation point and viewpoint from within the coordinate range of the distribution range information.

[0035] When the display information generation unit 14 receives display specification information from the point cloud selection unit 12, it transmits an acquisition request (point cloud acquisition request) for the display point cloud data corresponding to the point cloud data specification information and the display specification information to the point cloud processing unit 200A, and reads out the display point cloud data from the point cloud management unit 23A. As a result, the display information generation unit 14 reads out the display point cloud data corresponding to the point cloud data specification information, the fixation point setting instruction, and the viewpoint setting instruction from the point cloud management unit 23A.

[0036] When the point cloud selection unit 12 transmits new display specification information to the point cloud management unit 23A via the display information generation unit 14 and the point cloud management unit 23A registers new display point cloud data, the display information generation unit 14 reads out the registered new display point cloud data. As a result, the display information generation unit 14 reads out the latest display point cloud data registered in the point cloud management unit 23A.

[0037] The display information generation unit 14 causes the point cloud to be displayed on the screen display unit 13 using the display point cloud data. As a result, when the point cloud display system 1A displays the point cloud in a decimated manner, it eliminates the problem that the point cloud is locally displayed only in the vicinity of the fixation point, and can display the point cloud globally.

[0038] Note that the fixation point and the viewpoint may be changed at any timing. For example, the user of the client terminal 10 can also input a fixation point setting instruction and a viewpoint setting instruction to the screen operation unit 11 while viewing the displayed point cloud. That is, the fixation point and the viewpoint can be arbitrarily set and changed by the user of the client terminal 10.

[0039] When the user inputs an instruction to change the fixation point and the viewpoint to the screen operation unit 11 while viewing the point cloud displayed on the screen display unit 13, the point cloud selection unit 12 changes the display specification information and transmits the changed display specification information to the point cloud management unit 23A via the display information generation unit 14. The point cloud management unit 23A changes the display point cloud data according to the display specification information and stores the changed display point cloud data. That is, the point cloud management unit 23A sets the display priority according to the distance from the fixation point in each display area so that the number of point clouds to be displayed is equal to or less than the set number, and sets the point cloud with the node depth corresponding to the display priority in each display area. The display information generation unit 14 acquires the display point cloud data with the changed fixation point, viewpoint, and display range from the point cloud management unit 23A and displays the point cloud on the screen display unit 13. Thereby, the user of the client terminal 10 can observe the observation target in various directions from various angles.

[0040] Note that the display information generation unit 14 may receive the coordinates of the fixation point and the viewpoint from the point cloud management unit 23A. In this case, the coordinates of the fixation point and the viewpoint may be the default coordinates registered in the server 20A in advance, or the coordinates set by the user of the server 20A for each point cloud data. When the display information generation unit 14 receives the coordinates of the fixation point and the viewpoint from the point cloud management unit 23, the display information generation unit 14 may receive the display point cloud data from the server 20A without transmitting a point cloud acquisition request to the server 20A.

[0041] Incidentally, the display information generation unit 14 may execute the generation process of the display point cloud data. That is, the display information generation unit 14 may set a display priority according to the distance from the fixation point for each display area so that the number of point clouds to be displayed is equal to or less than the set point, and set a point cloud with a node depth corresponding to the display priority for each display area. Further, the display information generation unit 14 receives the designated point cloud (all display point cloud data) and the upsampled octree from the server 20A. The display information generation unit 14 causes the screen display unit 13 to display the point cloud using the designated point cloud and the upsampled octree.

[0042] As described above, in the point cloud processing unit 200A, the point cloud registration unit 22A registers the point cloud data in the upsampled octree, and the point cloud management unit 23A determines which nodes among the nodes of the upsampled octree are to be the point clouds to be displayed based on the display priority when displaying the point cloud.

[0043] In the first embodiment, since the points that the child nodes have in the parent node are arranged at a certain ratio (for example, 1 / 8), the number of point clouds is smaller for shallower nodes (higher parent nodes). Therefore, by the point cloud management unit 23A setting the point cloud data of deeper nodes for display areas with higher display priority, more point clouds will be displayed in display areas closer to the fixation point.

[0044] As described above, the point cloud display system 1A generates an upsampled octree for the designated point cloud and sets the display priority according to the distance from the fixation point. Then, the point cloud display system 1A increases the number of point clouds and increases the display density by displaying the point clouds of deeper nodes in areas with higher display priority, and decreases the number of point clouds and decreases the display density by displaying the point clouds of shallower nodes in areas with lower display priority. Thereby, when thinning out and displaying the point cloud, the point cloud display system 1A can eliminate the local display only at the fixation point.

[0045] Here, the point cloud registration process and display process executed by the point cloud display system 1A will be described. FIG. 2 is a diagram for explaining the point cloud registration process and display process executed by the point cloud display system according to the first embodiment.

[0046] The point group representation system 1A generates a top-down octree Tx for the point group data D1 of a specified point group to be represented, and registers the point group data in each node of the top-down octree Tx.

[0047] Specifically, the point group registration unit 22A sets a node N0, which is a node at the vertex (0th layer), for the entire three-dimensional space corresponding to the point group data D1. If the number of points included in this node N0 is equal to or greater than a specified number of points (for example, 100,000 points), the point group registration unit 22A divides the space region of the node N0 into eight parts. As a result, when the number of points included in the node N0 is equal to or greater than the specified number of points, the point group registration unit 22A sets eight child nodes in the space region of the node N0, which is the parent node. In FIG. 2, the eight child nodes of the first layer H1 set by the point group registration unit 22A in the space region of the node N0 are shown as N1 to N8.

[0048] Furthermore, the point group registration unit 22A divides the space region into eight parts for a node among the child nodes of the first layer H1 that contains a specified number of points or more. FIG. 2 shows a case where the point group registration unit 22A divides the first node (N1), which is the leftmost node among the eight child nodes of the first layer H1, and the sixth node (N6), which is the sixth node from the left, into eight parts each. As a result, the point group registration unit 22A sets eight child nodes in the space region of the first node (N1) of the first layer H1, and sets eight child nodes in the space region of the sixth node (N6) of the first layer H1. In FIG. 2, the eight child nodes of the second layer H2 set by the point group registration unit 22A in the space regions of the first node (N1) and the sixth node (N6) of the first layer H1 are shown as N1 to N8.

[0049] Furthermore, the point cloud registration unit 22A divides the space region into eight parts for the nodes among the child nodes of the second layer H2 that contain a specified number of points or more. FIG. 2 shows the case where the point cloud registration unit 22A divides the first node (N1) of the second layer H2 into eight parts. Thereby, the point cloud registration unit 22A sets eight child nodes in the space region of the first node (N1) of the second layer H2. In FIG. 2, the eight child nodes of the third layer H3 set by the point cloud registration unit 22A in the space region of the first node (N1) of the second layer H2 are denoted as N1 to N8. In this way, the point cloud registration unit 22A sets a structure in which the branching becomes more and more as the hierarchy gets deeper in the point cloud data D1.

[0050] The point cloud registration unit 22A incorporates the points of the child nodes into the parent node at a certain ratio. That is, the point cloud registration unit 22A sets a part of the data of the points of the nodes on the lower layer side in the nodes on the upper layer side.

[0051] For example, the point cloud registration unit 22A sets one-eighth of the point cloud data among the point cloud data included in each child node in the parent node. For example, when each node of the third layer H3 is a child node (N1 to N8) and the parent node is the first node (N1) of the second layer H2, the point cloud registration unit 22A incorporates one-eighth of the point cloud data among the point cloud data included in each child node (N1 to N8) of the third layer H3 into the first node (N1) of the second layer H2. As a result, less point cloud data than the data groups included in the child nodes (N1 to N8) of the third layer H3 is set in the first node (N1) of the second layer H2.

[0052] The point cloud registration unit 22A incorporates a certain ratio of the points of the child nodes into all the parent nodes. By this setting of incorporation, less point cloud data with a smaller number of points is set in the nodes of the upper layer side.

[0053] The point cloud management unit 23A sets the display priority based on the distance from the fixation point 31. The point cloud management unit 23A sets the space region 42 with the closest distance from the fixation point 31 in the three-dimensional space as the display region with the highest display priority. The space region 42 is a spherical region centered on the fixation point 31.

[0054] The point group management unit 23A sets the spatial region 43, which is the second closest to the fixation point 31 among the three-dimensional spaces, as the display region with the second highest display priority. The spatial region 43 is a spherical region centered on the fixation point 31 with a hollow center. The hollow part of the spatial region 43 is the spatial region 42. For example, the point group management unit 23A sets the spatial region 42, whose distance from the fixation point 31 in the three-dimensional space is less than the distance X1, to the highest display priority, and sets the spatial region 43, whose distance from the fixation point 31 is equal to or greater than the distance X1 and less than the distance X2 (>X1), to the second display priority.

[0055] In this way, the point group management unit 23A sets a higher display priority for the spatial regions closer to the fixation point 31. In the first embodiment, the point group management unit 23A sets the display priority based on the distance from the fixation point 31 regardless of the position of the viewpoint 40.

[0056] The point group management unit 23A sets nodes in deeper hierarchies for the spatial regions with higher display priorities. For example, for the spatial region 42 with the highest display priority, the point group management unit 23A sets the node in the deepest hierarchy. Also, for the spatial region 43 with the second highest display priority, the point group management unit 23A sets the node in the second deepest hierarchy. The point group management unit 23A may set the node in the shallowest hierarchy for the spatial region with the lowest display priority, or may make the point group non-displayed. Thereby, the point group management unit 23A determines the nodes in the shallower hierarchies for the display regions with lower display priorities as the point groups to be displayed, so that the decimation rate (the ratio of the number of points to be displayed to the number of point groups set in the display region), at which the points in the display regions with lower display priorities are decimated, is increased, and the decimation rate is decreased for the display regions with higher display priorities.

[0057] Since more point clouds are set for nodes at deeper levels, more point cloud data is set for display areas with higher display priorities. That is, the closer to the fixation point 31, the more point cloud data is set, and the farther from the fixation point 31, the less point cloud data is set. As a result, the closer the display area is to the fixation point 31, the higher the possibility that the display density of the point cloud will be.

[0058] The point cloud management unit 23A sets nodes for each spatial region of the three-dimensional region so that the total number of point clouds to be displayed is equal to or less than the set number. In other words, the point cloud management unit 23A sets nodes at a depth such that the number of point clouds to be displayed is equal to or less than the set number for each spatial region of the three-dimensional region. That is, the point cloud management unit 23A changes the nodes set for each spatial region of the three-dimensional region to higher-level nodes in order to make the number of point clouds to be displayed equal to or less than the set number. In this case, the point cloud management unit 23A sets nodes at deeper levels for spatial regions closer to the fixation point 31.

[0059] For example, the first display area may correspond to the first node at the Hx level, and the second display area may correspond to the second node at the Hx level. In this case, if the display priority of the first display area is higher than that of the second display area, the point cloud management unit 23A sets the parent node of the second node in the second display area. Since one-eighth of the point cloud data of the second node is stored in this parent node, the point cloud management unit 23A sets the stored one-eighth of the point cloud data in the second display area. As a result, the decimation rate of the second display area becomes eight times that of the first display area.

[0060] The point cloud management unit 23A causes the point clouds set for each spatial region of the three-dimensional space to be displayed on the screen display unit 13. The screen display unit 13 displays the point clouds at a higher density for spatial regions (display areas) with higher display priorities.

[0061] The screen display unit 13 displays the display area 32 corresponding to the spatial region 42 with the shortest distance from the fixation point 31 in the three-dimensional space using the point group with the lowest decimation rate (high-density point group). Further, the screen display unit 13 displays the display area 33 corresponding to the spatial region 43 with the second shortest distance from the fixation point 31 in the three-dimensional space using the point group with the second lowest decimation rate (medium-density point group). Further, the screen display unit 13 displays the display area 34 corresponding to the spatial region with the farthest distance from the fixation point 31 in the three-dimensional space using the point group with the highest decimation rate (low-density point group).

[0062] In this way, the client terminal 10 displays the point group such that the point group near the fixation point 31 has a high display density, and the display area away from the fixation point 31 displays the point group such that the display density is low instead of being non-displayed. Thereby, the point group display system 1A can eliminate the local display of the point group only around the fixation point 31 when thinning out and displaying the point group.

[0063] FIG. 3 is a flowchart showing the processing procedure of the point group display process executed by the point group display system according to Embodiment 1. The screen operation unit 11 of the client terminal 10 receives point group data designation information in which the user designates point group data (step S10). The client terminal 10 transmits the point group data designation information to the server 20A.

[0064] The point group registration unit 22A acquires the designated point group corresponding to the point group data designation information from the point group DB 21 (step S20). The point group registration unit 22A generates a top-down octree for the designated point group (step S30). The point group registration unit 22A stores the top-down octree and the designated point group in the point group management unit 23A (step S40).

[0065] The server 20A transmits distribution range information indicating the range of the coordinates of the designated point group to the client terminal 10. The client terminal 10 receives the position (coordinates) of the viewpoint and the fixation point from the user (step S50). Specifically, the screen operation unit 11 receives a viewpoint setting instruction for setting the coordinates of the viewpoint and a fixation point setting instruction for setting the coordinates of the fixation point from the user.

[0066] The client terminal 10 transmits a point cloud acquisition request, which is a request for acquiring the point cloud to be displayed, to the server 20A (step S60). This point cloud acquisition request includes display specification information (display range of the point cloud, fixation point setting instruction, and viewpoint setting instruction).

[0067] The point cloud processing unit 200A of the server 20A receives the point cloud acquisition request from the client terminal 10. The point cloud management unit 23A of the server 20A sets the fixation point and the viewpoint for the specified point cloud (step S70).

[0068] The point cloud management unit 23A sets a display priority according to the distance from the fixation point for each display area (step S82). The point cloud management unit 23A sets nodes with depths according to the display priority based on the upsampling octree so that the number of point clouds to be displayed is equal to or less than the set number (step S84). The point cloud management unit 23A sets the point cloud data of the nodes for each display area (step S86). The point cloud management unit 23A stores the display point cloud data including the point cloud data with the fixation point and the viewpoint set.

[0069] The display information generation unit 14 reads out the display point cloud data including the point cloud data with the fixation point and the viewpoint set from the point cloud management unit 23A. The display information generation unit 14 causes the point cloud of the display point cloud data to be displayed on the screen display unit 13 (step S90). That is, the display information generation unit 14 displays on the screen the point cloud corresponding to the point cloud data set for each display area. As a result, an image with a lower decimation rate and higher clarity is displayed the closer the distance from the fixation point is, and the decimated point cloud is also displayed in the display areas other than the vicinity of the fixation point. Note that the processes of steps S70, S82, S84, and S86 may be executed on the client terminal 10.

[0070] As described above, the point cloud display system 1A of the first embodiment determines nodes with shallower depths for the three-dimensional point cloud to be displayed in the display areas with lower display priorities, thereby increasing the decimation rate of the three-dimensional point cloud in the display areas with lower display priorities. Therefore, when displaying the point cloud in a decimated manner, the point cloud display system 1A can eliminate the local display of the point cloud.

[0071] Embodiment 2 Next, Embodiment 2 will be described with reference to FIGS. 4 to 6. In Embodiment 2, the point cloud is divided and managed into a plurality of upper octrees (layers), and the display and non-display of points are switched according to the distance between the viewpoint and the fixation point, etc.

[0072] FIG. 4 is a diagram showing the configuration of the point cloud display system according to Embodiment 2. Among the components in FIG. 4, components that achieve the same functions as those of the point cloud display system 1A of Embodiment 1 shown in FIG. 1 are denoted by the same reference numerals, and redundant descriptions are omitted.

[0073] The point cloud display system 1B of Embodiment 2 includes a server 20B instead of the server 20A as compared with the point cloud display system 1A. That is, the point cloud display system 1B includes the client terminal 10 and the server 20B.

[0074] The server 20B has a point cloud registration unit 22B instead of the point cloud registration unit 22A as compared with the server 20A. That is, the server 20B has the point cloud DB 21, the point cloud registration unit 22B, and the point cloud management unit 23A. The point cloud registration unit 22B and the point cloud management unit 23A are a point cloud processing unit 200B that registers point cloud data obtained by measuring the measurement target in an upper octree.

[0075] The point cloud registration unit 22B includes a normal registration unit 221 and a split registration unit 222. The normal registration unit 221 sets one octree for the specified point cloud in the same manner as the point cloud registration unit 22A of Embodiment 1. The point cloud registration unit 22B of Embodiment 2 can execute both the process using the normal registration unit 221 and the process using the split registration unit 222. Hereinafter, the case where the point cloud registration unit 22B executes the process using the split registration unit 222 will be described. Note that the point cloud registration unit 22B does not necessarily need to include the normal registration unit 221.

[0076] The division registration unit 222 divides the point cloud data of the specified point cloud and generates an octree for the divided point cloud data. The division registration unit 222 divides the specified point cloud into a plurality of layers and generates an octree for the point cloud data of each layer. The division registration unit 222 registers the generated octree and the specified point cloud in the point cloud management unit 23A.

[0077] Based on the viewpoint information, which is information on a specific position with respect to the viewpoint, the point cloud management unit 23A determines which layer among the layers is to be the point cloud to be displayed. Also, based on the display priority, the point cloud management unit 23A determines which node among the nodes of the octree structure of the divided point cloud data is to be the point cloud to be displayed.

[0078] The viewpoint information is, for example, the distance from the viewpoint to the fixation point. The point cloud management unit 23A determines, for example, based on the distance from the viewpoint to the fixation point, which layer among the layers is to be the point cloud to be displayed. Specifically, the point cloud management unit 23A sets the point cloud using more octrees (layers) as the distance from the viewpoint to the fixation point is closer, and sets the point cloud using fewer octrees as the distance from the viewpoint to the fixation point is farther. In other words, the point cloud management unit 23A sets the point cloud using a larger number of layers as the distance from the viewpoint to the fixation point set by the user is closer.

[0079] Here, the registration process and display process of the point cloud executed by the point cloud display system 1B will be described. FIG. 5 is a diagram for explaining the registration process and display process of the point cloud executed by the point cloud display system according to the second embodiment.

[0080] The point cloud display system 1B generates a plurality of octrees T1 to T3 for the point cloud data D1 of the point cloud to be displayed, and registers the point cloud data in each node of the octrees T1 to T3. That is, the point cloud display system 1B divides the point cloud data D1 and generates octrees T1 to T3 for each of the divided point cloud data.

[0081] For example, when the number of points in the point cloud data D1 is 120 million points and the maximum number of display points in each display area specified by the user is 3 million points, the division registration unit 222 divides it into 120 million ÷ 3 million = 40 point cloud data sets. That is, the division registration unit 222 sets 3 million sets of point cloud data with 40 points in each point cloud.

[0082] In this case, for example, when the number of layers of the display layer specified by the user is 3 layers, the division registration unit 222 divides 40 points by 3, and divides each set of point cloud data into 13 points each (13 points + 13 points + 14 points). That is, the division registration unit 222 divides the 40-point data point cloud into the 40×(N - 1)th (N is a natural number from 1 to 3 million) to the 40×(N - 1)+13th point data, the 40×(N - 1)+14th to 40×(N - 1)+26th point data, and the 40×(N - 1)+27th to 40×(N - 1)+40th point data. The division registration unit 222, for example, divides the first set of point cloud data into the 1st to 13th point data, the 14th to 26th point data, and the 27th to 40th point data. Also, the division registration unit 222 divides the second set of point cloud data into the 41st to 53rd point data, the 54th to 66th point data, and the 67th to 80th point data.

[0083] For each set of 40 points, the division registration unit 222 sets any one point data among the 40×(N - 1)+1st to 40×(N - 1)+13th point data in layer L1. Similarly, for each set of 40 points, the division registration unit 222 sets any one point data among the 40×(N - 1)+14th to 40×(N - 1)+26th point data in layer L2. Similarly, for each set of 40 points, the division registration unit 222 sets any one point data among the 40×(N - 1)+27th to 40×(N - 1)+40th point data in layer L3.

[0084] The division registration unit 222 sets, for example, for each set of 40 points, the 1st point, the 41st point, and the 81st point to layer L1, the 14th point, the 54th point, and the 94th point to layer L2, and the 27th point, the 67th point, and the 107th point to layer L3. The division registration unit 222 sets point data one by one to layers L1 to L3 for all 3 million sets of data point groups.

[0085] As a result, each of layers L1 to L3 will contain a point group of 3 million points. The point group management unit 23A determines the layer to be used for display based on the distance between the viewpoint and the fixation point. That is, the point group management unit 23A increases or decreases the number of layers to be used for display based on the distance between the viewpoint and the fixation point, and sets the maximum number of display points (decimation number) for each layer.

[0086] The point group management unit 23A sets more point group data of layers as the display target when the distance between the viewpoint and the fixation point is closer. For example, when there is a viewpoint in the sky and a fixation point on the ground, the point group management unit 23A calculates the distance from the position of the viewpoint in the sky to the fixation point on the ground, and sets more point group data of layers as the display target when the calculated distance is closer. On the other hand, the point group management unit 23A sets less point group data of layers as the display target when the viewpoint is farther from the fixation point.

[0087] Here, when the distance between the viewpoint and the fixation point is the closest, the point group management unit 23A sets the point group data of layers L1 to L3 as the display target. Also, when the distance between the viewpoint and the fixation point is the second closest, the point group management unit 23A sets the point group data of layers L1 and L2 as the display target. Also, when the distance between the viewpoint and the fixation point is the farthest, the point group management unit 23A sets the point group data of layer L1 as the display target.

[0088] Hereinafter, the display range when the distance between the viewpoint and the fixation point is the closest may be referred to as the close - distance region. Also, the display range when the distance between the viewpoint and the fixation point is the farthest may be referred to as the far - distance region. Also, the display range when the distance between the viewpoint and the fixation point is intermediate may be referred to as the mid - distance region.

[0089] When the point cloud management unit 23A displays the short-distance area, it downsamples the point cloud data of each of the layers L1 to L3 to point cloud data of 1 million points each. Further, when the point cloud management unit 23A displays the medium-distance area, it downsamples the point cloud data of each of the layers L1 and L2 to point cloud data of 1.5 million points each. Further, when the point cloud management unit 23A displays the long-distance area, it directly adopts the point cloud data of 3 million points without downsampling the point cloud data of the layer L1.

[0090] As a result, for the short-distance area, point cloud data of 1 million points each is set from 3 layers, for the medium-distance area, point cloud data of 1.5 million points each is set from 2 layers, and for the long-distance area, point cloud data of 3 million points is set from 1 layer.

[0091] When displaying the point cloud in three dimensions, the range of the point cloud shown on the screen becomes wider in the long-distance area and narrower in the short-distance area. In the case of the short-distance area, since the display range is narrow and the surrounding area outside the short-distance area is not displayed, the point cloud in the surrounding area is downsampled. That is, in the case of the short-distance area, the points in the range that will not be shown even if downsampled (the range not subject to downsampling) are downsampled as the point cloud outside the display range. The point cloud management unit 23A can suppress a decrease in the number of point cloud data in the short-distance area by downsampling the point cloud in the surrounding area outside the short-distance area. As a result, the point cloud management unit 23A can use the point cloud of the deep nodes among the point clouds of 3 layers for the short-distance area.

[0092] For example, the point cloud management unit 23A sets point cloud data of 1 million points each from 3 layers by downsampling the point cloud in the area outside the short-distance area. Since the point cloud management unit 23A uses the point cloud data of 3 layers for the short-distance area, the distance between points can be narrowed, and a high-density point cloud can be set. In this way, the point cloud management unit 23A can narrow the distance between points more than when using the point cloud data of 1 layer for the short-distance area. As a result, the point cloud management unit 23A can prevent a density difference in the point cloud from occurring in adjacent areas in the short-distance area.

[0093] Also, for the long-distance area, the point cloud management unit 23A uses the upsampled octree of layer L1. In this case, since the display range is wide in the long-distance area, the point cloud management unit 23A sets all the point clouds of layer L1 as display targets.

[0094] Since the upsampled octree of layer L1 is composed of data uniformly decimated from the specified point cloud, it is difficult for a density difference in the point cloud to occur due to decimation. Also, since the upsampled octree of layer L1 is a smaller upsampled octree than the upsampled octree used in Embodiment 1, the point cloud management unit 23A will set the point cloud of a shallower node than in Embodiment 1. Also, since the point cloud management unit 23A displays all the point clouds of layer L1, it is not affected by the decimation due to upsampling. Therefore, the point cloud management unit 23A can prevent a density difference in the point cloud from occurring even in adjacent areas in the long-distance area.

[0095] Also, the point cloud management unit 23A sets point cloud data of 1.5 million points for each of the two layers by decimating the point clouds in the peripheral areas other than the mid-distance area. Since the point cloud management unit 23A uses the point cloud data of two layers for the mid-distance area, the distance between points can be made narrower than in the long-distance area, and a medium-density point cloud can be set. In this way, the point cloud management unit 23A can make the distance between points narrower than when using the point cloud data of one layer for the mid-distance area. Thereby, the point cloud management unit 23A can prevent a density difference in the point cloud from occurring even in adjacent areas in the mid-distance area.

[0096] In this way, the point cloud display system 1B can make the density of the displayed point cloud uniform in any of the near-distance area, the mid-distance area, and the long-distance area, and can suppress the change in density between the display areas.

[0097] The screen display unit 13 displays the point cloud in the near-distance area using the point cloud data set in the near-distance area, displays the point cloud in the mid-distance area using the point cloud data set in the mid-distance area, and displays the point cloud in the long-distance area using the point cloud data set in the long-distance area.

[0098] That is, when the screen display unit 13 displays the short-distance area, it uses the point cloud data of layers L1 to L3. Also, when the screen display unit 13 displays the medium-distance area, it uses the point cloud data of layers L1 and L2. Further, when the screen display unit 13 displays the long-distance area, it uses the point cloud data of layer L1.

[0099] When displaying the point cloud, in the first display area and the second display area adjacent to each other, if the display priorities are the same in the first display area and the second display area, different nodes with the same depth are set. In this case, if there is a large difference between the number of point cloud data included in the node set in the first display area and the number of point cloud data included in the node set in the second display area, unless the point cloud is displayed by the point cloud display system 1B, the node boundary (the boundary between the first display area and the second display area) will be clearly displayed.

[0100] For example, there may be a case where the first node at the Hx level is set for the first display area and the second node at the Hx level is set for the second display area. In this case, if the number of point clouds of the first node at the Hx level in the first display area is more than the set number (for example, 100,000), this node becomes the parent node, and eight child nodes are set for this parent node. Then, one-eighth of the point cloud data from each child node is uploaded to the parent node. For example, when the parent node has 120,000 point clouds, these 120,000 point clouds are divided into eight and set for the child nodes. Then, a specific ratio (for example, one-eighth) of the point clouds from the child nodes is uploaded to the parent node. As a result, the number of point clouds of the first node at the Hx level in the first display area becomes 120,000÷8 = 15,000.

[0101] When the number of points in the point group of the second node at the Hx level of the second display area is less than the set number, no child nodes are set for this second node. When the number of points in the point group of this second node is 80,000, and the number of points in the point group of the first node is 15,000, there is a large difference between the number of points in the point group of the first node and the number of points in the point group of the second node. This difference will be displayed as a node boundary.

[0102] In Embodiment 2, the point cloud display system 1B divides the specified point cloud into a plurality of layers and generates a top-down octree for each layer. Then, since the point cloud display system 1B uses a larger number of layers to display the point cloud when the distance from the viewpoint to the fixation point is closer, it is possible to prevent a density difference in the point cloud from occurring in adjacent display areas and suppress the occurrence of node boundaries.

[0103] Note that the viewpoint information is not limited to the distance between the viewpoint and the fixation point. The viewpoint information may be the viewing angle. That is, the point cloud management unit 23A may determine the number of layers to be displayed based on the viewing angle, not limited to the distance between the viewpoint and the fixation point. The viewing angle is the angle formed by the line of sight, which is the line connecting the viewpoint and the fixation point, and the horizontal line. For example, when the distance between the fixation point and the viewpoint is closer than the reference distance, the point cloud management unit 23A sets more layers of point cloud data to be the display target as the viewing angle is larger (as the line-of-sight direction is closer to the directly downward direction).

[0104] For example, the division registration unit 222 sets six layers (layers L1 to L6) by dividing the point cloud data into six parts, and generates a total of six upward octrees for the divided point cloud data. In this case, when the distance between the viewpoint and the fixation point in the short-distance region is closer than the reference distance, the point cloud management unit 23A sets the point cloud data of more layers as the display target as the line-of-sight angle is larger. For example, when the line-of-sight angle in the short-distance region is less than 30 degrees, the point cloud management unit 23A sets the point cloud data of layers L1 to L3 and layer L4 as the display target. Also, when the line-of-sight angle in the short-distance region is 30 degrees or more and less than 60 degrees, the point cloud management unit 23A sets the point cloud data of layers L1 to L3 and layers L4 and L5 as the display target. Further, when the line-of-sight angle in the short-distance region is 60 degrees or more and 90 degrees or less, the point cloud management unit 23A sets the point cloud data of layers L1 to L3 and layers L4 to L6 as the display target.

[0105] Also, when the ground to be displayed is a slope, the viewpoint information may be the distance between the lowest position on the ground and the viewpoint. That is, when the ground to be displayed is a slope, the point cloud management unit 23A may determine the number of layers of the display target based on the distance between the lowest position on the ground and the viewpoint, or may determine the number of layers of the display target based on the distance between the average height of the ground and the viewpoint. The lowest position on the ground is the point at the lowest position (the bottommost point) among the point cloud.

[0106] When the ground to be displayed is a slope, the point cloud management unit 23A sets a larger number of layers as the display target as the distance between the lowest position on the ground and the viewpoint is closer. Also, when the ground to be displayed is a slope, the point cloud management unit 23A sets a larger number of layers as the display target as the distance between the average height of the ground and the viewpoint is closer.

[0107] As described above, in the second embodiment, the point cloud display system 1B divides the point cloud data and generates a top-down octree for the divided point cloud data. As a result, the point cloud display system 1B can display the point cloud using a top-down octree smaller than when the top-down octree is not divided, so that the point cloud data of nodes shallower than when not divided can be set as the display target. Therefore, the point cloud display system 1B can prevent the occurrence of a density difference in the point cloud in adjacent display areas and can display a uniformly distributed point cloud.

[0108] FIG. 6 is a flowchart showing the processing procedure of the point cloud display process executed by the point cloud display system according to the second embodiment. Among the processes shown in FIG. 6, the same process numbers as those shown in FIG. 3 are assigned to the same processes, and duplicate descriptions are omitted.

[0109] Compared with the server 20A, the server 20B in the second embodiment executes the processes of steps S31 and S32 instead of step S30, and executes the process of step S41 instead of step S40. Further, compared with the server 20A, the server 20B executes the processes of steps S81, S82, and S85 instead of steps S82 and S84. Further, the point cloud display system 1B executes the processes of steps S10, S20, S50 to S70, S86, and S90 in the same manner as the point cloud display system 1A.

[0110] In the point cloud display system 1B, after the process of step S20 is executed, the division registration unit 222 of the point cloud registration unit 22B divides the specified point cloud by the specified number of point clouds (for example, 3 million points) (step S31). Further, the division registration unit 222 generates a top-down octree with the specified number of layers (for example, 3 layers) for the specified point cloud (step S32). That is, the division registration unit 222 distributes a part of the points included in the divided point cloud to any layer and generates a top-down octree for the point cloud distributed to each layer. The division registration unit 222 stores the top-down octree for each layer and the specified point cloud in which the specified point cloud and the top-down octree for each layer are associated with each other in the point cloud management unit 23A (step S41).

[0111] After the process of step S70, the point cloud management unit 23A determines the octree (layer) to be applied to the display area based on the distance from the viewpoint to the fixation point (step S81). Note that the point cloud management unit 23A may determine the octree to be applied to the display area based on the distance from the viewpoint to the ground. Also, the point cloud management unit 23A may determine the octree to be applied to the display area based on the line-of-sight angle.

[0112] The point cloud management unit 23A sets the octree of a larger number of layers as the distance from the viewpoint to the fixation point is closer. Also, the point cloud management unit 23A sets the octree of a larger number of layers as the distance from the viewpoint to the ground is closer. Also, the point cloud management unit 23A sets the octree of a larger number of layers for the display area with a larger line-of-sight angle.

[0113] The point cloud management unit 23A sets the display priority according to the distance from the fixation point for each display area (step S82). The point cloud management unit 23A sets the nodes at a depth corresponding to the display priority for the determined octree so that the number of point clouds to be displayed is equal to or less than the set number (step S85). Specifically, the point cloud management unit 23A sets the point cloud of deeper nodes as the distance from the fixation point is closer, and sets the point cloud of shallower nodes as the distance from the fixation point is farther. The point cloud management unit 23A sets the point cloud data of the nodes for each display area (step S86).

[0114] The display information generation unit 14 reads out the display point cloud data including the point cloud data with the fixation point and the viewpoint set from the point cloud management unit 23A. The display information generation unit 14 causes the point cloud of the display point cloud data to be displayed on the screen display unit 13 (step S90). Thereby, an image with a uniform density is displayed, and the decimated point cloud is also displayed in the display area other than the vicinity of the fixation point.

[0115] In this way, the point cloud display system 1B manages the point cloud by dividing it into a plurality of top-down octrees (layers), and switches the display and non-display of points according to the distance between the viewpoint and the fixation point, etc., so that the difference in the density of the point cloud is less likely to occur as a whole. Therefore, the point cloud display system 1B can display a natural image in which node boundaries are less likely to occur. Note that the processes of steps S70, S81, S82, S85, and S86 may be executed by the client terminal 10.

[0116] In this way, in the second embodiment, the point cloud display system 1B manages the point cloud by dividing it into a plurality of top-down octrees (layers), and displays the point cloud using a larger number of layers as the distance between the viewpoint and the fixation point is closer, so that it is possible to suppress the occurrence of a density difference in the point cloud between display regions.

[0117] Embodiment 3. Next, Embodiment 3 will be described with reference to FIGS. 7 to 9. In Embodiment 3, the display priority of the spatial region close to the line of sight is increased, and the display priority of the spatial region close to the viewpoint is also increased.

[0118] FIG. 7 is a diagram showing the configuration of the point cloud display system according to Embodiment 3. Among the components in FIG. 7, components that achieve the same functions as the point cloud display systems 1A and 1B are denoted by the same reference numerals, and redundant descriptions are omitted.

[0119] The point cloud display system 1C of Embodiment 3 includes a server 20C instead of the server 20B as compared with the point cloud display system 1B. That is, the point cloud display system 1B includes the client terminal 10 and the server 20C.

[0120] The server 20C has a point cloud management unit 23C instead of the point cloud management unit 23A as compared with the server 20B. That is, the server 20C has a point cloud DB 21, a point cloud registration unit 22B, and a point cloud management unit 23C. The point cloud registration unit 22B and the point cloud management unit 23C are a point cloud processing unit 200C that registers point cloud data obtained by measuring the measurement target in a top-down octree.

[0121] The point cloud management unit 23C includes a fixation point priority unit 231 and a gaze priority unit 232. Similar to the point cloud registration unit 22A in Embodiment 1, the fixation point priority unit 231 sets a higher display priority for a display area closer to the fixation point.

[0122] The point cloud management unit 23C in Embodiment 3 can execute both the process using the fixation point priority unit 231 and the process using the gaze priority unit 232. Hereinafter, the case where the point cloud management unit 23C executes the process using the gaze priority unit 232 will be described.

[0123] The gaze priority unit 232 sets a display priority for each spatial area based on the distance from the gaze line. Further, the gaze priority unit 232 sets a display priority for each spatial area based on the distance from the viewpoint. The gaze priority unit 232 sets a higher display priority as the distance from the gaze line is closer and as the distance from the viewpoint is closer. Thereby, the gaze priority unit 232 displays a point cloud with a higher density as the distance from the gaze line is closer and as the distance from the viewpoint is closer.

[0124] Note that the point cloud display system 1C may or may not include either the normal registration unit 221 or the divided registration unit 222. Further, the point cloud display system 1C may not include the fixation point priority unit 231.

[0125] Here, the point cloud registration process and the display process executed by the point cloud display system 1C will be described. FIG. 8 is a diagram for explaining the point cloud registration process and the display process executed by the point cloud display system according to Embodiment 3. A line connecting the viewpoint 40 and the fixation point 31 is the gaze line 51.

[0126] The line-of-sight priority unit 232 sets a display priority for each spatial region based on the distance from the line of sight 51. The line-of-sight priority unit 232 sets a higher display priority for a spatial region closer to the line of sight 51. For example, the line-of-sight priority unit 232 sets the spatial region 52, which is the closest to the line of sight 51 among the three-dimensional spaces, as the display region with the highest display priority. When the spatial region 52 is cut by a plane including the line of sight 51, the cross-sectional shape of the spatial region 52 may be an elliptical shape, or may be the shape of a land vehicle combining a straight line and a semi-circular shape.

[0127] The line-of-sight priority unit 232 sets the spatial region 53, which is the second closest to the line of sight 51 among the three-dimensional spaces, as the display region with the second highest display priority. The spatial region 53 is a region surrounding the spatial region 52. When the spatial region 53 is cut by a plane including the line of sight 51, the inner and outer circumferences of the cross-sectional shape of the spatial region 53 may each be an elliptical shape, or may be the shape of a land vehicle combining a straight line and a semi-circular shape.

[0128] The line-of-sight priority unit 232 further sets a display priority within the spatial regions 52 and 53 based on the distance from the viewpoint 40. The line-of-sight priority unit 232 sets a higher display priority for a spatial region closer to the viewpoint 40 with respect to the spatial region 52. Similarly, the line-of-sight priority unit 232 sets a higher display priority for a spatial region closer to the viewpoint 40 with respect to the spatial region 53. For example, the line-of-sight priority unit 232 sets the position of the viewpoint 40 within the three-dimensional space as the spatial region with the highest display priority within the spatial region 52. The line-of-sight priority unit 232 decreases the display priority within the spatial region 52 as it moves away from the viewpoint 40 along the direction of the arrow shown in FIG. 8. Similarly, the line-of-sight priority unit 232 decreases the display priority within the spatial region 53 as it moves away from the viewpoint 40 along the direction of the arrow shown in FIG. 8.

[0129] In this way, the line-of-sight priority unit 232 sets a display priority for each spatial region within the three-dimensional space based on the distance from the line of sight 51 and the distance from the viewpoint 40.

[0130] FIG. 9 is a flowchart showing the processing procedure of the point cloud display process executed by the point cloud display system according to Embodiment 3. Among the processes shown in FIG. 9, the same process as the process shown in FIG. 6 is given the same step number code, and duplicate explanations are omitted.

[0131] Compared with the server 20B, the server 20C in Embodiment 3 executes the process of step S83 instead of step S82. Also, the server 20C executes the processes of steps S10 to S70, S81, S85, S86, and S90 in the same manner as the server 20B.

[0132] After the process of step S70, the point cloud registration unit 22B determines the octree for upload to be applied to the display area based on the distance from the viewpoint to the fixation point (step S81).

[0133] The gaze priority unit 232 sets the display priority according to the gaze and the distance from the viewpoint for each display area included in the display area 30 (step S83). Specifically, the gaze priority unit 232 sets a higher display priority as the distance from the gaze is closer and as the distance from the viewpoint is closer.

[0134] The gaze priority unit 232 sets nodes at a depth corresponding to the display priority for the determined octree for upload so that the number of point clouds to be displayed is equal to or less than the set number (step S85). The gaze priority unit 232 sets the point cloud data of the nodes in each display area (step S86).

[0135] The display information generation unit 14 reads out the display point cloud data including the point cloud data with the fixation point and the viewpoint set from the point cloud management unit 23C. The display information generation unit 14 causes the point cloud of the display point cloud data to be displayed on the screen display unit 13 (step S90). Thereby, the point cloud display system 1C can display an image with a lower decimation rate and higher clarity as the distance from the gaze and the viewpoint is closer, and can also display the decimated point cloud in the display area other than the vicinity of the fixation point.

[0136] Furthermore, the point cloud display system 1C sets a higher display priority as the distance from the line of sight is closer and as the distance from the viewpoint is closer, so that it is possible to prevent the point cloud near the viewpoint from becoming invisible. For example, even when the viewpoint is near the ground and the fixation point is in the far horizontal direction, the point cloud display system 1C can prevent the point cloud near the viewpoint from being thinned out and becoming invisible, and can clearly display the vicinity of the viewpoint. Note that the processes of steps S70, S81, S83, S85, and S86 may be executed by the client terminal 10.

[0137] As described above, in the third embodiment, since the point cloud display system 1C increases the display priority of the spatial region close to the line of sight and increases the display priority of the spatial region close to the viewpoint, it is possible to prevent the point cloud near the line of sight and the viewpoint from becoming invisible, and the vicinity of the line of sight and the viewpoint can be clearly displayed.

[0138] Fourth Embodiment. Next, the fourth embodiment will be described with reference to FIGS. 10 and 11. In the fourth embodiment, the processes executed in the first to third embodiments are realized by one computer.

[0139] FIG. 10 is a diagram showing the configuration of a point cloud display device according to the fourth embodiment. Among the components of FIG. 10, components that achieve the same functions as the point cloud display systems 1A to 1C are denoted by the same reference numerals, and redundant descriptions are omitted.

[0140] The point cloud display device 2 according to Embodiment 4 has the same functions as any of the point cloud display systems 1A to 1C. When the point cloud display device 2 executes the same processing as the point cloud display system 1A, it includes a screen operation unit 11, a point cloud selection unit 12, a screen display unit 13, a display information generation unit 14, a point cloud DB 21, a point cloud registration unit 22A, and a point cloud management unit 23A. Further, when the point cloud display device 2 executes the same processing as the point cloud display system 1B, it includes a screen operation unit 11, a point cloud selection unit 12, a screen display unit 13, a display information generation unit 14, a point cloud DB 21, a point cloud registration unit 22B, and a point cloud management unit 23A. Further, when the point cloud display device 2 executes the same processing as the point cloud display system 1C, it includes a screen operation unit 11, a point cloud selection unit 12, a screen display unit 13, a display information generation unit 14, a point cloud DB 21, a point cloud registration unit 22B, and a point cloud management unit 23C. Note that the point cloud display device 2 may include a screen operation unit 11, a point cloud selection unit 12, a screen display unit 13, a display information generation unit 14, a point cloud DB 21, a point cloud registration unit 22A, and a point cloud management unit 23C.

[0141] When the point cloud display device 2 executes the same processing as the point cloud display system 1A, the point cloud registration unit 22A and the point cloud management unit 23A are the point cloud processing unit 200A. When the point cloud display device 2 executes the same processing as the point cloud display system 1B, the point cloud registration unit 22B and the point cloud management unit 23A are the point cloud processing unit 200B. When the point cloud display device 2 executes the same processing as the point cloud display system 1C, the point cloud registration unit 22B and the point cloud management unit 23C are the point cloud processing unit 200C.

[0142] As described above, in Embodiment 4, the point cloud registration unit is either the point cloud registration unit 22A or 22B, and the point cloud management unit is either the point cloud management unit 23A or 23C. Hereinafter, the case where the point cloud display device 2 executes the same processing as the point cloud display system 1A will be described.

[0143] FIG. 11 is a flowchart showing the processing procedure of the point group display process executed by the point group display device according to Embodiment 4. The processing of steps S110 to S170 and S190 executed by the point group display device 2 is the same as the processing of steps S10 to S70 and S90 executed by the point group display system 1A.

[0144] That is, the screen operation unit 11 of the point group display device 2 receives point group data designation information in which the user designates point group data (step S110). The screen operation unit 11 transmits the point group data designation information received from the user to the point group selection unit 12 and the display information generation unit 14. The point group selection unit 12 transmits the point group data designation information to the point group registration unit 22A and the display information generation unit 14.

[0145] The point group registration unit 22A acquires the designated point group corresponding to the point group data designation information from the point group DB 21 (step S120). The point group registration unit 22A generates an octree for the designated point group (step S130).

[0146] The point group registration unit 22A stores the octree and the designated point group in the point group management unit 23A (step S140).

[0147] The point group processing unit 200A transmits distribution range information indicating the range of the coordinates of the designated point group to the display information generation unit 14. The point group display device 2 receives the positions (coordinates) of the viewpoint and the fixation point from the user (step S150). Specifically, the screen operation unit 11 receives a viewpoint setting instruction for setting the coordinates of the viewpoint and a fixation point setting instruction for setting the coordinates of the fixation point from the user.

[0148] The display information generation unit 14 transmits a point group acquisition request, which is a request for acquiring the point group to be displayed, to the point group processing unit 200A (step S160). This point group acquisition request includes display designation information (the display range of the point group, the fixation point setting instruction, and the viewpoint setting instruction).

[0149] The point cloud processing unit 200A receives a point cloud acquisition request from the display information generation unit 14. The point cloud management unit 23A sets a fixation point and a viewpoint for the specified point cloud (step S170).

[0150] The point cloud management unit 23A sets a display priority and nodes for each display area (step S180). That is, the point cloud management unit 23A executes the processes of steps S82 and S84 described with reference to FIG. 3. Specifically, the point cloud management unit 23A sets a display priority according to the distance from the fixation point for each display area. The point cloud management unit 23A sets nodes at a depth according to the display priority so that the number of point clouds to be displayed is equal to or less than the set number.

[0151] When the point cloud display device 2 executes the same processes as the point cloud display system 1B, in the point cloud display device 2, the point cloud management unit 23B executes the processes of steps S81, S82, and S85 described with reference to FIG. 6 as the process of step S180.

[0152] When the point cloud display device 2 executes the same processes as the point cloud display system 1C, in the point cloud display device 2, the point cloud registration unit 22C executes the processes of steps S81, S83, and S85 described with reference to FIG. 9 as the process of step S180.

[0153] The point cloud management unit 23A sets the point cloud of nodes for each display area (step S185). The display information generation unit 14 reads out the display point cloud data including the point cloud data with the fixation point and the viewpoint set from the point cloud management unit 23A. The display information generation unit 14 causes the screen display unit 13 to display the point cloud of the display point cloud data (step S190). As a result, an image with a lower decimation rate is displayed as the distance from the line of sight and the viewpoint is closer, and the decimated point cloud is also displayed in the display area other than the vicinity of the fixation point. Note that the processes of steps S170, S180, and S185 may be executed by the display information generation unit 14.

[0154] As described above, in the fourth embodiment, the point cloud display device 2 determines a shallower node as the three-dimensional point cloud to be displayed for a display area with a lower display priority, thereby increasing the decimation rate of the three-dimensional point cloud for a display area with a lower display priority. Therefore, similar to the first to third embodiments, the point cloud display device 2 can eliminate the local display of the point cloud when subsampling and displaying the point cloud.

[0155] Next, the hardware configuration of the point cloud display device 2 will be described. The point cloud display device 2 is realized by a processing circuit. This processing circuit may be a processor and a memory that execute a program stored in the memory, or may be dedicated hardware. The processing circuit is also called a control circuit.

[0156] FIG. 12 is a diagram showing a configuration example of a processing circuit when the processing circuit included in the point cloud display device according to the fourth embodiment is realized by a processor and a memory. The processing circuit 90 shown in FIG. 12 is a control circuit and includes a processor 91 and a memory 92. When the processing circuit 90 is composed of the processor 91 and the memory 92, each function of the processing circuit 90 is realized by software, firmware, or a combination of software and firmware. The software or firmware is described as a program and stored in the memory 92. In the processing circuit 90, the processor 91 reads and executes the program stored in the memory 92 to realize each function. That is, the processing circuit 90 includes a memory 92 for storing a point cloud display program for which the processing of the point cloud display device 2 will be ultimately executed. It can also be said that this point cloud display program is a program for causing the point cloud display device 2 to execute each function realized by the processing circuit 90. This point cloud display program may be provided by a storage medium in which the program is stored, or may be provided by other means such as a communication medium.

[0157] The point cloud display program executed by the point cloud display device 2 has a module configuration including a screen operation unit 11, a point cloud selection unit 12, a display information generation unit 14, a point cloud registration unit 22A, and a point cloud management unit 23A. These are loaded onto the main memory device and are generated on the main memory device.

[0158] When the point cloud display device 2 executes the same processing as the point cloud display system 1B, the point cloud display program has a module configuration including a screen operation unit 11, a point cloud selection unit 12, a display information generation unit 14, a point cloud registration unit 22B, and a point cloud management unit 23A. These are loaded onto the main memory device and are generated on the main memory device.

[0159] When the point cloud display device 2 executes the same processing as the point cloud display system 1C, the point cloud display program has a module configuration including a screen operation unit 11, a point cloud selection unit 12, a display information generation unit 14, a point cloud registration unit 22B, and a point cloud management unit 23C. These are loaded onto the main memory device and are generated on the main memory device.

[0160] Here, the processor 91 is, for example, a CPU (Central Processing Unit), a processing device, an arithmetic device, a microprocessor, a microcomputer, or a DSP (Digital Signal Processor), etc. Also, the memory 92 corresponds to, for example, a non-volatile or volatile semiconductor memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable ROM), an EEPROM (registered trademark) (Electrically EPROM), a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, or a DVD (Digital Versatile Disc).

[0161] FIG. 13 is a diagram showing an example of a processing circuit included in the point group display device according to Embodiment 4 when the processing circuit is configured by dedicated hardware. The processing circuit 93 shown in FIG. 13 corresponds to, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination thereof.

[0162] Regarding the processing circuits 90 and 93, part of them may be realized by dedicated hardware and part of them may be realized by software or firmware. In this way, the processing circuits 90 and 93 can realize the above-described respective functions by dedicated hardware, software, firmware, or a combination thereof.

[0163] Note that the point group display device 2 may be realized by one processing circuit or may be realized by a plurality of processing circuits. Also, the client terminals 10 and the servers 20A to 20C have the same hardware configuration as the point group display device 2 described with reference to FIGS. 12 and 13.

[0164] Here, an example of the point group displayed by the point group display systems 1A to 1C of Embodiments 1 to 3 will be described. FIG. 14 is a diagram showing a point group display image when a point group is thinned out using a general octree and a point group display image displayed by the point group display system of Embodiment 1. FIG. 14 shows point group display images F1 and F2 when the line is viewed from above the line. The central portions of the point group display images F1 and F2 are the viewpoints and the fixation points.

[0165] The point group display image F1 is an image displayed when the point group is thinned out using a general octree, and the point group display image F2 is an image displayed by the point group display system 1A of Embodiment 1.

[0166] When a point cloud is decimated using a general octree, the point cloud is left centered around the fixation point, and the point cloud in the outer peripheral part of the image is decimated. That is, in the point cloud display image F1 when the point cloud is decimated using a general octree, only the leaf nodes (nodes having no child nodes) among the octree nodes become the point cloud to be displayed. For this reason, in the point cloud display image F1, only the vicinity of the fixation point (the central part of the point cloud display image F1) is the object of point cloud display, and the peripheral part of the point cloud display image F1 does not become the object of point cloud display. As a result, when a general octree is used, the area where the point cloud is displayed and the area where it is not displayed are clearly separated, making it difficult to understand the situation of the peripheral part of the point cloud display image F1.

[0167] On the other hand, the point cloud display system 1A of Embodiment 1 generates a point cloud display image F2 in which the decimation rate is lower as the distance from the fixation point is closer and higher as the distance from the fixation point is farther. Thereby, the point cloud display system 1A can display a point cloud display image F2 in which the point cloud is decimated and arranged over a wide range centered around the fixation point. Therefore, the point cloud display system 1A can eliminate the local display of the point cloud when displaying the decimated point cloud.

[0168] FIG. 15 is a diagram showing a point cloud display image when the point cloud is decimated using one top-down octree and a point cloud display image displayed by the point cloud display system of Embodiment 2. In FIG. 15, point cloud display images F3 and F4 when viewing a line from above the line are shown. The central parts of the point cloud display images F3 and F4 are the viewpoint and the fixation point.

[0169] The point cloud display image F3 is an image displayed when the point cloud is decimated using one top-down octree, and the point cloud display image F4 is an image to be displayed by the point cloud display system 1B of Embodiment 2.

[0170] In the point cloud display image F3 when the point cloud is decimated using one top-down octree, node boundaries may be clearly displayed at the boundary between the decimated area and the non-decimated area.

[0171] On the other hand, the point cloud display system 1B of Embodiment 2 divides the point cloud into a plurality of top-down octrees, and generates a point cloud display image F4 using a larger number of layers (top-down octrees) as the distance from the viewpoint to the fixation point is shorter. As a result, the point cloud display system 1B can display the point cloud of shallower nodes than when using a single top-down octree, so that it is possible to prevent the occurrence of a density difference (density unevenness) of the point cloud in adjacent regions and display a uniformly distributed point cloud.

[0172] FIG. 16 is a diagram showing a point cloud display image when thinning out the point cloud centered on the fixation point and a point cloud display image displayed by the point cloud display system of Embodiment 3. In FIG. 16, point cloud display images F5 and F6 are shown when looking from the line to the back direction of the line. In the point cloud display images F5 and F6, the line is the viewpoint and the fixation point is set in the back direction of the line.

[0173] The point cloud display image F5 is an image displayed when thinning out the point cloud centered on the fixation point, and the point cloud display image F6 is an image to be displayed by the point cloud display system 1C of Embodiment 3.

[0174] In the point cloud display image F5 when thinning out the point cloud centered on the fixation point, when there is a fixation point in the far horizontal direction (the depth direction of the line), the point cloud near the fixation point is displayed, but the point cloud near the viewpoint is not displayed.

[0175] On the other hand, the point cloud display system 1C of Embodiment 3 generates a point cloud display image F6 that preferentially displays the region close to the line of sight and the region close to the viewpoint. As a result, the point cloud display system 1C can clearly display the point cloud near the line of sight and the viewpoint.

[0176] The configurations shown in the above embodiments are examples, and it is possible to combine them with other known techniques, combine the embodiments with each other, and omit or change a part of the configuration without departing from the gist.

[0177] Hereinafter, aspects of the present disclosure will be collectively described as appendices.

[0178] (Appendix 1) A server that stores the three-dimensional point cloud data of the measurement target obtained by measuring the measurement target, A point cloud display device that displays a three-dimensional point cloud corresponding to the three-dimensional point cloud data, and has, The server, registers the three-dimensional point cloud data in an octree structure, and based on the display priority when displaying the three-dimensional point cloud, determines which nodes among the nodes of the octree structure are to be the three-dimensional point cloud to be displayed, and includes a point cloud processing unit, The point cloud processing unit, by determining that the shallower nodes in the display area with lower display priority are the three-dimensional point cloud to be displayed, increases the decimation rate of the three-dimensional point cloud in the display area with lower display priority, The point cloud display device, displays the three-dimensional point cloud with a higher decimation rate in the display area with lower display priority, A point cloud display system characterized by this. (Appendix 2) The point cloud processing unit, sets child nodes by dividing the space of the parent node of the octree structure, and sets the three-dimensional point cloud data of the parent node by uploading a specific ratio of the three-dimensional point cloud data among the three-dimensional point cloud data of the child nodes to the parent node, generates the octree structure with the three-dimensional point cloud data set in the parent node as an up-tree octree, and determines the three-dimensional point cloud to be displayed based on the up-tree octree, The point cloud display system according to Appendix 1, characterized by this. (Appendix 3) The point cloud processing unit, sets a higher display priority for the display area closer to the fixation point set in the display area, The point cloud display system according to Appendix 1 or 2, characterized by this. (Appendix 4) The point cloud processing unit, sets a higher display priority for the display area closer to the viewpoint set in the display area, The point cloud display system according to Appendix 1 or 2, characterized by this. (Appendix 5) The point cloud processing unit sets a higher display priority for a display area closer to the line of sight set in the display area. The point cloud display system according to Appendix 1 or 2, characterized in that. (Appendix 6) The point cloud processing unit divides the three-dimensional point cloud data into a plurality of layers, registers each of the divided three-dimensional point cloud data in a divided octree structure that is an octree structure, and determines which layer of the layers is the three-dimensional point cloud to be displayed based on viewpoint information that is information on a specific position with respect to the viewpoint, and determines which node of the nodes in the divided octree structure is the three-dimensional point cloud to be displayed based on the display priority. The point cloud display system according to any one of Appendices 1 to 5, characterized in that. (Appendix 7) The point cloud processing unit uses a larger number of layers as the three-dimensional point cloud to be displayed when the distance from the viewpoint set in the display area to the fixation point set in the display area is shorter. The point cloud display system according to Appendix 6, characterized in that. (Appendix 8) The point cloud processing unit uses a larger number of layers as the three-dimensional point cloud to be displayed when the distance from the viewpoint set in the display area to the lowest point among the point clouds set in the display area is shorter. The point cloud display system according to Appendix 6, characterized in that. (Appendix 9) The point cloud processing unit uses a larger number of layers as the three-dimensional point cloud to be displayed when the angle formed by the line of sight set in the display area and the horizontal line is larger. The point cloud display system according to Appendix 6, characterized in that. (Appendix 10) a storage unit that stores the three-dimensional point cloud data of the measurement target obtained by measuring the measurement target; Register the three-dimensional point cloud data in an octree structure, and determine which nodes among the nodes of the octree structure are to be used as the three-dimensional point cloud to be displayed based on the display priority when displaying the three-dimensional point cloud corresponding to the three-dimensional point cloud data. A point cloud processing unit A display unit that displays the three-dimensional point cloud corresponding to the three-dimensional point cloud data Comprising The point cloud processing unit By determining that the shallower the node in the display area with a lower display priority is the three-dimensional point cloud to be displayed, the decimation rate of the three-dimensional point cloud is increased as the display area with a lower display priority is The display unit displays the three-dimensional point cloud with a higher decimation rate in the display area with a lower display priority A point cloud display device characterized by the above (Appendix 11) A server that stores the three-dimensional point cloud data of the measurement target obtained by measuring the measurement target registers the three-dimensional point cloud data in an octree structure, and based on the display priority when displaying the three-dimensional point cloud corresponding to the three-dimensional point cloud data, determines which nodes among the nodes of the octree structure are to be used as the three-dimensional point cloud to be displayed. A point cloud processing step A display step in which a point cloud display device displays the three-dimensional point cloud corresponding to the three-dimensional point cloud data Including In the point cloud processing step The server determines that the shallower the node in the display area with a lower display priority is the three-dimensional point cloud to be displayed, so that the decimation rate of the three-dimensional point cloud is increased as the display area with a lower display priority is In the display step The point cloud display device displays the three-dimensional point cloud with a higher decimation rate in the display area with a lower display priority A point cloud display method characterized by the above (Appendix 12) Register the three-dimensional point cloud data of the measurement object obtained by measuring the measurement object in an octree structure, and determine which nodes among the nodes of the octree structure are to be used as the three-dimensional point cloud to be displayed based on the display priority when displaying the three-dimensional point cloud corresponding to the three-dimensional point cloud data. A point cloud processing step; A display step of displaying the three-dimensional point cloud corresponding to the three-dimensional point cloud data; Cause a computer to execute, In the point cloud processing step, By determining that the shallower the node in the display area with a lower display priority is the three-dimensional point cloud to be displayed, the decimation rate of the three-dimensional point cloud is increased as the display area with a lower display priority; In the display step, Display the three-dimensional point cloud with a higher decimation rate in the display area with a lower display priority. A point cloud display program characterized by the above.

Explanation of Signs

[0179] 1A~1C Point cloud display system, 2 Point cloud display device, 10 Client terminal, 11 Screen operation unit, 12 Point cloud selection unit, 13 Screen display unit, 14 Display information generation unit, 20A~20C Server, 21 Point cloud DB, 22A,22B Point cloud registration unit, 23A,23C Point cloud management unit, 31 Fixation point, 32,33,34 Display area, 40 Viewpoint, 42,43,52,53 Spatial area, 51 Line of sight, 90,93 Processing circuit, 91 Processor, 92 Memory, 200A~200C Point cloud processing unit, 221 Normal registration unit, 222 Division registration unit, 231 Fixation point priority unit, 232 Line of sight priority unit, D1 Point cloud data, F1~F6 Point cloud display image, H1 First layer, H2 Second layer, H3 Third layer, L1~L6 Layer, T1~T3,Tx Top-down octree.

Claims

1. A server that stores the three-dimensional point cloud data of the measurement target obtained by measuring the measurement target, A point cloud display device that displays a three-dimensional point cloud corresponding to the three-dimensional point cloud data, having, The server registers the three-dimensional point cloud data in an octree structure, and based on the display priority when displaying the three-dimensional point cloud, determines which nodes among the nodes of the octree structure are to be the three-dimensional point cloud to be displayed, and includes a point cloud processing unit, The point cloud processing unit By determining that the shallower the node in the display area with a lower display priority is the three-dimensional point cloud to be displayed, the decimation rate of the three-dimensional point cloud is increased as the display area with a lower display priority, The point cloud display device Displays the three-dimensional point cloud with a higher decimation rate in the display area with a lower display priority, A point cloud display system characterized by this.

2. The point cloud processing unit Sets child nodes by dividing the space of the parent node of the octree structure, and sets the three-dimensional point cloud data of the parent node by uploading a specific ratio of the three-dimensional point cloud data among the three-dimensional point cloud data of the child nodes to the parent node, generates the octree structure as an upload octree, and determines the three-dimensional point cloud to be displayed based on the upload octree, The point cloud display system according to claim 1, characterized by this.

3. The point cloud processing unit Sets a higher display priority for the display area closer to the fixation point set in the display area, The point cloud display system according to claim 1 or 2, characterized by this.

4. The point cloud processing unit Sets a higher display priority for the display area closer to the viewing point set in the display area, The point cloud display system according to claim 1 or 2, characterized in that...

5. The point cloud processing unit sets a higher display priority for a display area closer to the line of sight set in the display area. The point cloud display system according to claim 1 or 2, characterized in that...

6. The point cloud processing unit divides the three-dimensional point cloud data into a plurality of layers, registers each of the divided three-dimensional point cloud data in a divided octree structure that is an octree structure, and determines which layer among the layers is the three-dimensional point cloud to be displayed based on viewpoint information that is information on a specific position with respect to the viewpoint, and determines which node among the nodes of the divided octree structure is the three-dimensional point cloud to be displayed based on the display priority. The point cloud display system according to claim 1, characterized in that...

7. The point cloud processing unit sets a larger number of layers as the three-dimensional point cloud to be displayed when the distance from the viewpoint set in the display area to the fixation point set in the display area is shorter. The point cloud display system according to claim 6, characterized in that...

8. The point cloud processing unit sets a larger number of layers as the three-dimensional point cloud to be displayed when the distance from the viewpoint set in the display area to the lowest point among the point clouds set in the display area is shorter. The point cloud display system according to claim 6, characterized in that...

9. The point cloud processing unit sets a larger number of layers as the three-dimensional point cloud to be displayed when the angle formed by the line of sight set in the display area and the horizontal line is larger. The point cloud display system according to claim 6, characterized in that...

10. A storage unit that stores the three-dimensional point cloud data of the measurement target obtained by measuring the measurement target; A point cloud processing unit that registers the three-dimensional point cloud data in an octree structure and determines which nodes among the nodes of the octree structure are to be the three-dimensional point cloud to be displayed based on the display priority when displaying the three-dimensional point cloud corresponding to the three-dimensional point cloud data; A display unit that displays the three-dimensional point cloud corresponding to the three-dimensional point cloud data; Comprising; The point cloud processing unit; By determining that the shallower nodes are the three-dimensional point cloud to be displayed for the display areas with lower display priority, the decimation rate of the three-dimensional point cloud is increased for the display areas with lower display priority; The display unit displays the three-dimensional point cloud with a higher decimation rate for the display areas with lower display priority. A point cloud display device characterized by the above.

11. A server that stores the three-dimensional point cloud data of the measurement target obtained by measuring the measurement target registers the three-dimensional point cloud data in an octree structure and determines which nodes among the nodes of the octree structure are to be the three-dimensional point cloud to be displayed based on the display priority when displaying the three-dimensional point cloud corresponding to the three-dimensional point cloud data, a point cloud processing step; A display step in which a point cloud display device displays the three-dimensional point cloud corresponding to the three-dimensional point cloud data; Including; In the point cloud processing step; The server determines that the shallower nodes are the three-dimensional point cloud to be displayed for the display areas with lower display priority, thereby increasing the decimation rate of the three-dimensional point cloud for the display areas with lower display priority; In the display step; The point cloud display device displays the three-dimensional point cloud with a higher decimation rate for the display areas with lower display priority. A point cloud display method characterized by the above.

12. Register the three-dimensional point cloud data of the measurement object obtained by measuring the measurement object in an octree structure, and based on the display priority when displaying the three-dimensional point cloud corresponding to the three-dimensional point cloud data, determine which nodes among the nodes of the octree structure are to be used as the three-dimensional point cloud to be displayed. A point cloud processing step; A display step of displaying the three-dimensional point cloud corresponding to the three-dimensional point cloud data; Cause a computer to execute; In the point cloud processing step; By determining that the shallower the node in the display area with a lower display priority is the three-dimensional point cloud to be displayed, the decimation rate of the three-dimensional point cloud is increased as the display area with a lower display priority; In the display step; Display the three-dimensional point cloud with a higher decimation rate in the display area with a lower display priority; A point cloud display program characterized by the above.

Images