Rendering device and program thereof, and ray information reduction device and program thereof

Abstract

To provide a rendering device capable of reducing a data volume of a point cloud having ray information.SOLUTION: A rendering device 1 includes: a point group reading unit 10 which reads a point group K having ray information; a ray direction averaging unit 11 which averages ray directions contained in the ray information acquired by the same type of sensors; a view point direction calculation unit 12 which calculates a view point direction from the arrangement position of a three-dimensional object to the view point position; a ray contribution calculation unit 13 which calculates contribution of the averaged ray direction to the view point direction; a drawing ray information selection unit 14 which selects pieces of ray information corresponding to the rays whose average ray directions are calculated for the previously set number sequentially starting with the averaged ray directions having higher contribution, and generates a new point group K' having the ray information; and a drawing unit which generates images from the new point group K' having the ray information and a camera parameter of a virtual camera corresponding to the view point position.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a rendering device and a program therefor, and a light ray information reduction device and a program therefor. [Background technology]

[0002] In recent years, the use of 3D models has been expanding. In addition to the traditional presentation of 2D images, various uses are expanding, including presentation by VR (Virtual Reality) using HMD (Head Mounted Display), presentation by AR (Augmented Reality) that displays virtual 3D objects over real camera images, and a representation method called xR (Cross Reality) that combines these two.

[0003] A point cloud format has been known as a model for describing the shape of a subject. A point cloud is a method for expressing a shape as a set of points with three-dimensional coordinates, and may also record color information (e.g., red, green, and blue components) and normal information (e.g., x-axis, y-axis, and z-axis components) for each component point of the point cloud. A well-known and widely used technique is to reconstruct a three-dimensional shape from images captured by a sensor such as a camera as a time-series three-dimensional point cloud, and then play back the reconstructed point cloud in order to enjoy the image as a three-dimensional image. Compared to conventional two-dimensional images, this three-dimensional image is also called volumetric image because it contains three-dimensional information.

[0004] Light field information is also known as a method for describing 3D images. Light field information can be expressed in four degrees of freedom, consisting of a position on the image plane perpendicular to the optical axis (two dimensions) and the direction of a ray of light (two dimensions) toward that position, or in five degrees of freedom, describing the direction of a ray of light (two dimensions) originating from a point on the surface or inside of an object (three dimensions). For example, by including ray information in a point cloud, the point cloud is expressed in eight dimensions, including directional information (θ,φ) relating to the direction of rays from the coordinates (x, y, z) of the vertex to the sensor (camera) that acquired the information used to generate the point cloud, and pixel value information (R, G, B). Furthermore, the directional information in the ray information is expressed in a polar coordinate system of (θ, φ), but it may also be expressed in a Cartesian coordinate system of (x, y, z). In this way, a rendering method has been disclosed in which light ray information is added to a point cloud to present a natural texture depending on the viewpoint (see Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2023-008697 Summary of the Invention [Problem to be solved by the invention]

[0006] The technique described in Patent Document 1 is advantageous in that it can produce rendering results that present a natural texture. On the other hand, when a viewer is freely able to change the viewpoint position and direction to obtain the rendering results of a 3D object, such as in VR or AR presentations, in order to comfortably view the 3D image, it is necessary to obtain the rendering results according to the viewpoint position and direction in a short calculation time, that is, quickly even if frame updates are performed frequently.

[0007] However, when attempting to process a large amount of ray information, as in the method described in Patent Document 1, ray information is written for each vertex, and so it is necessary to process an amount of data equal to the number of vertices multiplied by the number of pieces of ray information. In this case, with conventional methods, as the number of vertices increases, the amount of calculations increases accordingly, making it difficult to provide interactive presentations.

[0008] Therefore, an object of the present invention is to provide a rendering device and a program therefor that can reduce the amount of data of a point cloud with ray information, as well as a ray information reduction device and a program therefor. [Means for solving the problem]

[0009] In order to solve the above problem, the rendering device of the present invention is a rendering device that generates an image corresponding to a viewpoint position from a point cloud with ray information representing a three-dimensional object, and is configured to include a point cloud reading unit, a ray direction averaging unit, a viewpoint direction calculation unit, a ray contribution calculation unit, a drawing ray information selection unit, and a drawing unit.

[0010] In such a configuration, the rendering device reads a point cloud with ray information for each frame of the video using the point cloud reading unit. Then, the rendering device uses a ray direction averaging unit to calculate an average ray direction by averaging the ray directions contained in the ray information obtained by the same sensor among the ray information corresponding to the number of multiple ray rays associated with each vertex of the point group with ray information. Furthermore, the rendering device calculates the viewpoint direction from the arrangement position of the three-dimensional object to the viewpoint position by the viewpoint direction calculation unit.

[0011] The rendering device then uses the ray contribution calculation unit to calculate, for each average ray direction corresponding to the number of rays, a contribution in which the smaller the angle with the viewpoint direction, the greater the degree of contribution. Then, the rendering device uses the drawing ray information selection unit to select a predetermined number of ray information corresponding to the ray whose average ray direction has been calculated, in order from the average ray direction with the greatest contribution, and generates a new point group with ray information. This reduces the amount of ray information that contributes less.

[0012] The rendering device then generates an image for each frame using the drawing unit from the point cloud with ray information generated by the drawing ray information selection unit and the camera parameters of the virtual camera corresponding to the viewpoint position. This allows the rendering device to perform rendering while reducing the amount of data of the point cloud with ray information. The rendering device can be operated by a program that causes a computer to function as a rendering device.

[0013] In addition, in order to solve the above problem, the light ray information reduction device of the present invention is a light ray information reduction device that reduces the amount of data of a point cloud with light ray information representing a three-dimensional object, and is configured to include a point cloud reading unit, a ray direction averaging unit, a viewpoint direction calculation unit, a ray contribution calculation unit, and a drawing light ray information selection unit.

[0014] In such a configuration, the light ray information reduction device reads a point cloud with light ray information for each frame of the video using the point cloud reading unit. Then, the light ray information reduction device uses a light ray direction averaging unit to calculate an average light ray direction by averaging the light ray directions included in the light ray information acquired by the same sensor among the light ray information corresponding to the number of multiple light rays associated with each vertex of the point cloud with light ray information. Furthermore, the light ray information reduction device calculates the viewpoint direction from the arrangement position of the three-dimensional object to the viewpoint position by the viewpoint direction calculation unit.

[0015] The light ray information reduction device then calculates, by the light ray contribution calculation unit, for each average light ray direction corresponding to the number of light rays, a contribution in which the degree of contribution increases as the angle with the viewpoint direction decreases. Then, the light ray information reduction device uses the drawing light ray information selection unit to select a predetermined number of pieces of light ray information corresponding to the light rays whose average ray directions have been calculated, in order from the average ray direction with the greatest contribution, and generates a new point group with light ray information.

[0016] This allows the light ray information reduction device to reduce the amount of data of the point cloud with light ray information, while leaving only the light ray information that contributes to the viewpoint direction. The light ray information reduction device can be operated by a program that causes a computer to function as the light ray information reduction device. [Effects of the Invention]

[0017] According to the present invention, the amount of data of a point cloud with ray information can be reduced by adapting it to the viewing direction. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a block diagram showing the configuration of a rendering device according to an embodiment of the present invention. [Figure 2] FIG. 10 is an explanatory diagram for explaining a point group with ray information. [Figure 3] FIG. 10 is an explanatory diagram illustrating an example of the configuration of a point group with ray information. [Figure 4] 1A and 1B are explanatory diagrams for explaining the contents of a memory structure for storing a point group with ray information, in which FIG. 1A shows a vertex information structure and FIG. 1B shows a ray information structure. [Figure 5] 2 is an explanatory diagram for explaining a method for selecting ray information of a drawing target in the drawing ray information selection unit of FIG. 1. FIG. [Figure 6] 4 is a flowchart illustrating an operation of the rendering device according to the embodiment of the present invention. [Figure 7] 1 is a block diagram showing a configuration of a light ray information reduction device according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. <Rendering device configuration> The configuration of a rendering device 1 according to an embodiment of the present invention will be described with reference to FIG.

[0020] The rendering device 1 generates an image (viewpoint image) corresponding to a viewpoint position from a point cloud (point cloud data) with ray information that represents a three-dimensional object. The rendering device 1 generates a viewpoint image corresponding to a viewpoint position p from a predetermined placement position w of the three-dimensional object in a virtual space (which is the center of the world coordinates) and camera parameters cp when photographing the three-dimensional object with a virtual camera at an arbitrary viewpoint position p. As shown in FIG. 1, the rendering device 1 includes a point cloud reading unit 10, a ray direction averaging unit 11, a viewpoint direction calculation unit 12, a ray contribution calculation unit 13, a drawing ray information selection unit 14, and a drawing unit 15.

[0021] The point cloud reading unit 10 reads a point cloud with ray information for each frame of the video. Here, the point group with ray information will be described with reference to FIG. The point cloud K with ray information represents the shape of a three-dimensional object as a point cloud consisting of multiple vertices, and also adds ray direction information to each vertex. The point group K with ray information can be generated by a known photogrammetry technique (for example, the technique described in Japanese Patent Application Laid-Open No. 2023-8697).

[0022] As shown in Fig. 2, the point cloud K with ray information is captured by cameras C (C1, ..., C M It was generated using photogrammetry technology from multiple images of subject H taken in a volumetric studio or similar where a 3D model of the subject H is placed. The point group K with ray information is configured by associating vertex information with a plurality of pieces of ray information acquired by a plurality of sensors (cameras) for vertices V that make up the point group.

[0023] The vertex information is the position (three-dimensional coordinates) of the vertex in the virtual space. For example, the vertex V1 has (x1, y1, z1) as the vertex information Q1, and the vertex V N is the vertex information Q N As (x N ,y N ,zN ) where N is the number of vertices.

[0024] The light ray information is information that identifies the light rays at the vertices, and includes the light ray direction, color information, etc. for the number of sensors (number of light rays) acquired by a plurality of sensors. Specifically, the ray direction is information indicating the direction from the vertex V to the sensor (camera C) (for example, the azimuth angle φ and the elevation angle θ). The color information is information indicating the color value of the vertex V (for example, the RGB value).

[0025] For example, vertex V1 is connected to camera C1 using ray information L 11 :(θ 11 ,φ 11 ,R 11 ,G 11 ,B 11 ),…,Camera C M The light ray information L corresponding to 11 :(θ 1M ,φ 1M ,R 1M ,G 1M ,B 1M ) has light ray information for M light rays (M is the number of cameras). Also, for example, vertex V N is the light ray information L corresponding to camera C1. N1 :(θ N1 ,φ N1 ,R N1 ,G N1 ,B N1 ),…,Camera C M The light ray information L corresponding to NM :(θ NM ,φ NM ,R NM ,G NM ,B NM ) has light ray information for the number of M light rays. Note that for a vertex V that is not photographed by a certain camera C, all values ​​of the light ray information corresponding to the camera C that cannot photograph it are set to an indefinite value (for example, "0"). That is, the point group K with ray information is made up of vertices V1,...,V N For each, one vertex and cameras C1,…,C M The light beam information is associated with a plurality of light beams corresponding to the number of light beams. Returning to FIG. 1, the configuration of the rendering device 1 will be further described.

[0026] The point cloud reading unit 10 receives a point cloud K with ray information, in which a plurality of pieces of ray information are associated with each piece of vertex information shown in FIG. Here, the point cloud reading unit 10 reads the input point cloud K with ray information from the same cameras (sensors) C1, . . . , C M The light ray information acquired by the above is collected and rearranged in a memory (not shown) and stored. For example, as shown in FIG. 4(a), the point cloud reading unit 10 reads the vertex information as vertices V1, . . . , V N 4(b), the point cloud reader 10 stores the ray information in the memory as a vertex information structure arranged in order. M For each ray information of vertices V1,…,V N The ray information structures are stored in memory in order. This makes it possible to access the ray information for each camera at high speed compared to accessing the ray information corresponding to each camera for a large number of vertices.

[0027] The point cloud reading unit 10 stores the point cloud K with ray information in the format of the structure shown in FIG. 4 for each frame in a memory, and notifies the ray direction averaging unit 11 that it has been read. The point group K with ray information stored in the memory is referenced by the ray direction averaging unit 11 and the drawing ray information selection unit 14, which will be described later.

[0028] The ray direction averaging unit 11 calculates an average ray direction (direction vector) by averaging the ray directions included in the ray information acquired by the same sensor (camera) among the ray information corresponding to the number of multiple rays associated with each vertex of the point group K with ray information. Specifically, the light ray direction averaging unit 11 calculates the light ray information L1 (L 11 ,…,L N1 ) of the ray direction (θ 11 ,φ11 ),…,(θ N1 ,φ N1 ) and calculate the average ray direction L d1 (θ c1av ,φ c1av ) is calculated. Similarly, the light direction averaging unit 11 detects the camera C M The corresponding ray information L M (L 1M ,…,L NM ) in the direction (θ 1M ,φ 1M ),…,(θ NM ,φ NM ) and calculate the average ray direction L dM (θ cMav ,φ cMav ) is calculated. The average ray direction may be calculated using a polar coordinate system of (θ, φ) or a Cartesian coordinate system of (x, y, z).

[0029] The light direction averaging unit 11 detects the direction of the other cameras C2, . . . , C M-1 Similarly, the ray directions of the ray information corresponding to the average ray direction L d2 ,…,L dM-1 Calculate. The light ray direction averaging unit 11 outputs the average light ray direction for each piece of light ray information corresponding to the camera to the light ray contribution calculation unit 13 .

[0030] The viewpoint direction calculation unit 12 calculates the viewpoint direction from the arrangement position of the three-dimensional object to the viewpoint position. Here, the viewpoint direction calculation unit 12 calculates the viewpoint direction d from the placement position w of the three-dimensional object to the viewpoint position p, based on the placement position w of the three-dimensional object and the three-dimensional position (viewpoint position p) of the virtual camera included in the camera parameters cp of the virtual camera capturing the three-dimensional object. The placement position w of the three-dimensional object is, for example, the center of a circle in a volumetric studio where multiple cameras are arranged around the circumference. Note that this placement position w may be at a predetermined height from the floor. Viewpoint direction calculation unit 12 calculates a viewpoint direction d (direction vector) (d=pw) by subtracting arrangement position w, which is a three-dimensional coordinate, from viewpoint position p, which is a three-dimensional coordinate. Viewpoint direction calculation unit 12 outputs the calculated viewpoint direction d to light ray contribution calculation unit 13.

[0031] The light ray contribution calculation unit 13 calculates the contribution for each average light ray direction corresponding to the number of light rays, with the degree of contribution increasing as the angle formed with the viewing direction decreases. That is, the closer the average light ray direction calculated by the light ray direction averaging unit 11 is to the viewpoint direction d calculated by the viewpoint direction calculation unit 12, the greater the contribution calculated by the light ray contribution calculation unit 13.

[0032] Specifically, the light ray contribution calculation unit 13 calculates the average light ray direction L for each camera calculated by the light ray direction averaging unit 11. d1 ,…,L dM and the viewpoint direction d, and calculate the dot product of the direction vectors, and calculate the contribution CO i (i=1, ..., M). Here, if the ray direction is a polar coordinate system of (θ, φ) and the viewpoint direction is a three-dimensional Cartesian coordinate system of (x, y, z), the ray contribution calculation unit 13 can convert one of the coordinate systems into the other coordinate system and then find the dot product.

[0033] In this case, if the contribution (value of the dot product) is a positive value, the angle between the viewing direction and the average ray direction is acute, and the larger the value, the smaller the angle between the viewing direction and the average ray direction. If the contribution is "0", the angle between the viewing direction and the average ray direction is 90 degrees. If the contribution is a negative value, the angle between the viewing direction and the average ray direction is an obtuse angle. The light ray contribution calculation unit 13 outputs the contribution for each average light ray direction to the drawing light ray information selection unit 14 .

[0034] The drawing ray information selection unit 14 selects a predetermined number of ray information corresponding to the ray whose average ray direction has been calculated, in descending order of the average ray direction with the greatest contribution calculated by the ray contribution calculation unit 13, and generates a new point group with ray information.

[0035] That is, the drawing ray information selection unit 14 selects the ray information of the cameras C1, . . . , C2 in the ray information structure shown in FIG. M Among the ray information corresponding to i A preset number of pieces of ray information are selected in descending order of (i=1, ..., M). Note that the rendering ray information selection unit 14 does not select pieces of ray information corresponding to average ray directions whose contribution rate is "0" or less, even if the number is less than the preset number.

[0036] For example, as shown in FIG. 5, the drawing ray information selection unit 14 selects the light rays in ascending order of the angle formed with the viewpoint direction d from the virtual camera CV placed at the viewpoint position (L dM ,L d1 ,L dM-1 , . . . ), a preset number of ray directions are identified, and ray information corresponding to the identified ray directions is selected as the rendering target. In the example of Figure 5, the average light ray direction L d2 ,L d3 The light ray information corresponding to the above is not included in the rendering target.

[0037] The drawing ray information selection unit 14 selects only the vertex information corresponding to the ray information selected in the ray information structure of Figure 4(b) from the vertex information shown in the vertex information structure of Figure 4(a), and associates the corresponding ray information with the selected vertex information. This allows the rendering ray information selection unit 14 to delete ray information that is not to be rendered from the point group K with ray information, thereby generating a point group K' with ray information in which the amount of data is reduced. The rendering ray information selection unit 14 outputs the selected and generated point group K′ with ray information to the rendering unit 15.

[0038] The rendering unit 15 generates (renders) an image for each frame from the point group K' with ray information generated by the rendering ray information selection unit 14 and the camera parameters cp of the virtual camera input from outside. The camera parameters cp are information for associating the point group K' with ray information on the world coordinate system with image coordinates, and include the optical principal point position of the lens (viewpoint position p), the camera attitude, the size and arrangement of pixels of the image sensor, the focal length of the lens, etc. The drawing unit 15 may use a known rendering method, such as the rendering device described in Japanese Patent Application Laid-Open No. 2023-8697.

[0039] With the configuration described above, the rendering device 1 can generate images of three-dimensional objects faster than conventional methods by reducing the amount of data by reducing the amount of ray information that contributes little to the rendering of point clouds with ray information. The rendering device 1 can be operated by a program (rendering program) that causes a computer (not shown) to function as each of the above-mentioned units.

[0040] <Rendering device operation> Next, the operation of the rendering device 1 will be described with reference to FIG. 6 (and as appropriate, with reference to FIG. 1 for the configuration).

[0041] In step S1, the point cloud reader 10 reads a point cloud K with ray information for each frame of an image. At this time, the point cloud reader 10 reads vertex information into the vertices V1, ..., V N The point cloud reader 10 stores the vertex information structure in memory, in which the vertices are arranged in order. M For each ray information of vertices V1,…,V N The ray information is stored in memory in a sequentially arranged structure. In step S2, the light ray direction averaging unit 11 initializes an index i for identifying light ray information (i←1).

[0042] In step S3, the light ray direction averaging unit 11 calculates the i-th light ray information L i The ray directions are averaged to obtain the average ray direction L di Calculate. In step S4, the light ray direction averaging unit 11 determines whether or not the index i has reached the number M of light ray information, which is the number of light rays set at the vertex. Here, if the index i has not yet reached M (No in step S4), in step S5, the light direction averaging unit 11 increments the index i (i←i+1) and returns the operation to step S3.

[0043] On the other hand, if the index i has reached M (Yes in step S4), then in step S6, the viewpoint direction calculation unit 12 calculates the viewpoint direction d from the arrangement position w of the three-dimensional object and the viewpoint position p. In step S7, the light ray contribution calculation unit 13 initializes an index i for identifying the light ray direction (i←1).

[0044] In step S8, the light ray contribution calculation unit 13 calculates the i-th average light ray direction L di The dot product of the vector of the viewpoint direction d calculated in step S6 is calculated as the contribution CO i It is calculated as follows. In step S9, the light ray contribution calculation unit 13 determines whether or not the index i has reached the number M of light ray information, which is the number of light rays set at the vertex. Here, if the index i has not yet reached M (No in step S9), in step S10, the light ray contribution calculation unit 13 increments the index i (i←i+1) and returns the operation to step S8.

[0045] On the other hand, if the index i reaches M (Yes in step S9), in step S11, the drawing ray information selection unit 14 selects the degree of contribution CO i A preset number of pieces of ray information corresponding to the rays whose average ray direction has been calculated are selected in descending order of the number (i=1, . . . , M), and a new point group K' with ray information is generated. This allows ray information that contributes little to rendering to be deleted, thereby reducing the amount of data in the point cloud with ray information.

[0046] In step S12, the rendering unit 15 renders the point group K' with ray information generated by reducing the amount of data in step S14 as an image based on the camera parameters cp of the virtual camera input from the outside. Through the above operations, the rendering device 1 can reduce ray information that does not contribute to the viewpoint position, and generate an image of a three-dimensional object faster than conventional methods.

[0047] Although the embodiment of the present invention has been described above, the present invention is not limited to this embodiment. Here, the rendering ray information selection unit 14 selects a preset number of pieces of ray information, but the number may be variable depending on the image to be rendered. For example, if it is desired to render an image more realistically, the number of pieces of ray information may be increased, and if it is desired to further reduce the processing load on the rendering device 1, the number of pieces of ray information may be decreased.

[0048] Also, although an example in which the present invention is configured as the rendering device 1 has been shown here, the drawing unit 15 may be omitted from the configuration and the present invention may be configured as a light ray information reduction device. FIG. 7 shows the configuration of a light information reduction device 2 according to an embodiment of the present invention. The light ray information reduction device 2 reduces the amount of data of a point cloud with light ray information that represents a three-dimensional object. The light ray information reduction device 2 includes a point cloud reading unit 10, a light ray direction averaging unit 11, a viewpoint direction calculation unit 12, a light ray contribution calculation unit 13, and a rendering light ray information selection unit . Since each component is the same as that of the rendering device 1 described in FIG. 1, the same components are denoted by the same reference numerals and the description thereof will be omitted. The light ray information reduction device 2 can be operated by a program (light ray information reduction program) that causes a computer (not shown) to function as each of the above-mentioned units. Furthermore, the operation of the light ray information reduction device 2 can be achieved by omitting the processing of step S12 from the operation of the rendering device 1 described with reference to FIG. By configuring and operating the light ray information reduction device 2 in this way, the light ray information reduction device 2 can reduce light ray information that contributes little to rendering of a point cloud with light ray information. [Explanation of symbols]

[0049] 1. Rendering Device 10 Point cloud reading section 11 Ray direction averaging section 12 Viewpoint direction calculation unit 13 Ray contribution calculation unit 14 Drawing ray information selection section 15 Drawing section 2 Ray information reduction device Point cloud with K-ray information

Claims

1. A rendering device that generates an image corresponding to a viewpoint position from a point cloud with ray information that represents a three-dimensional object, a point cloud reader that reads a point cloud with ray information for each frame of the video; a light ray direction averaging unit that calculates an average light ray direction by averaging light ray directions included in light ray information acquired by the same sensor among light ray information corresponding to a plurality of numbers of light rays associated with each vertex of the point cloud with light ray information; a viewpoint direction calculation unit that calculates a viewpoint direction from the arrangement position of the three-dimensional object to a viewpoint position; a light ray contribution calculation unit that calculates a contribution degree for each average light ray direction corresponding to the number of light rays, the degree of contribution increasing as the angle formed with the viewpoint direction decreases; a rendering ray information selection unit that selects a predetermined number of pieces of ray information corresponding to the ray whose average ray direction has been calculated in descending order of the average ray direction having the greatest contribution, and generates a new point cloud with ray information; a drawing unit that generates an image for each frame from the point cloud with ray information generated by the drawing ray information selection unit and camera parameters of a virtual camera corresponding to the viewpoint position; A rendering device comprising:

2. The rendering device described in claim 1, characterized in that the point cloud reading unit rearranges and stores the point cloud with light ray information, in which multiple pieces of light ray information are associated with each vertex information indicating the coordinates of the vertices, in memory by grouping the light ray information acquired by the same sensor.

3. 2. The rendering device according to claim 1, wherein the light ray contribution calculation unit calculates, as the contribution, an inner product of a direction vector of the viewpoint direction and the average light ray direction.

4. The rendering device according to claim 3, characterized in that the drawing ray information selection unit does not select ray information corresponding to an average ray direction whose contribution rate is "0" or less, even if it is less than the predetermined number.

5. A program for causing a computer to function as the rendering device according to any one of claims 1 to 4.

6. A ray information reduction device that reduces the amount of data of a point cloud with ray information representing a three-dimensional object, comprising: a point cloud reader that reads a point cloud with ray information for each frame of the video; a light ray direction averaging unit that calculates an average light ray direction by averaging light ray directions included in light ray information acquired by the same sensor among light ray information corresponding to a plurality of numbers of light rays associated with each vertex of the point cloud with light ray information; a viewpoint direction calculation unit that calculates a viewpoint direction from the arrangement position of the three-dimensional object to a viewpoint position; a light ray contribution calculation unit that calculates a contribution degree for each average light ray direction corresponding to the number of light rays, the degree of contribution increasing as the angle formed with the viewpoint direction decreases; a rendering ray information selection unit that selects a predetermined number of pieces of ray information corresponding to the ray whose average ray direction has been calculated in descending order of the average ray direction having the greatest contribution, and generates a new point cloud with ray information; A light ray information reduction device comprising:

7. A program for causing a computer to function as the light beam information reduction device according to claim 6.

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