A method for calculating total reflection radiation brightness of a multi-radiation source and a light ray tracing method

Abstract

The application relates to the technical field of light ray tracing, and discloses a multi-radiation-source total reflected radiation brightness calculation method and a light ray tracing method. The multi-radiation-source total reflected radiation brightness calculation method comprises the following steps: S1, initializing a radiation source; S2, calculating reflected light ray radiation brightness; S3, calculating radiation source radiation brightness; S4, calculating the opening angle of the radiation source to a reflection point; and S5, calculating total reflected radiation brightness. The application solves the problems of slow calculation speed, high calculation complexity, and a large number of sampled light rays in the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ray tracing, and particularly relates to a method for calculating total reflected radiance of multiple radiation sources and a ray tracing method. BACKGROUND

[0002] In the inverse Monte Carlo ray tracing algorithm, the radiance of a certain wall surface to be reflected needs to be calculated by randomly sampling a plurality of rays in the 2π solid angle of the wall surface, and the average radiance is an unbiased estimate of the radiance of the wall surface. However, different random sampling schemes have an impact on the calculation efficiency and accuracy of the radiance.

[0003] The infrared simulation technology combining the inverse Monte Carlo method with the ray tracing algorithm can solve the problem of infrared simulation in a complex scene, avoid solving a super-large linear equation system, and flexibly handle more types of scene targets other than typical wall surfaces. However, in the traditional ray tracing algorithm, if there is a strong infrared radiation source in the scene, the radiance distribution in the 2π solid angle of the wall surface will be uneven, and in order to achieve the same calculation accuracy, the number of sampled rays needs to be greatly increased, which will greatly slow down the calculation speed.

[0004] In the prior art, for example, in the patent “Radiation source sampling weight determination method for multi-radiation source scene rendering and related equipment” (application number: CN202011360803.X, publication number: CN114549730A) applied by Huawei Technologies Co., Ltd., a method for determining the sampling weight of a radiation source in a multi-radiation source scene is proposed, which includes: obtaining a to-be-rendered scene in a multi-radiation source scene at a target rendering perspective, and obtaining a plurality of radiation sources set in the multi-radiation source scene; performing single-radiation-source ray tracing rendering on the to-be-rendered scene at the target rendering perspective to obtain a plurality of first rendering images corresponding to the to-be-rendered scene under the illumination of each radiation source; and determining the radiation source sampling weight of each radiation source at the target rendering perspective according to the irradiation information in the plurality of first rendering images. This method has the advantage of high calculation accuracy, but the process of determining the weight has high computational complexity, the number of sampled rays is large, and the calculation speed is slow. SUMMARY

[0005] To overcome the shortcomings of the prior art, the present application provides a method for calculating total reflected radiance of multiple radiation sources and a ray tracing method, which solves the problems of slow calculation speed, high calculation complexity, and a large number of sampled rays in the prior art.

[0006] The technical solution adopted by the present application to solve the above problems is as follows:

[0007] A method for calculating total reflected radiance of multiple radiation sources, comprising the following steps:

[0008] S1, initializing the radiation source: collecting self-information of all radiation sources in the scene;

[0009] S2, calculating the reflected light radiation luminance: calculating the reflected light radiation luminance L0 according to the reflection law;

[0010] S3, calculating the radiation source radiation luminance: calculating the radiation luminance L i of each radiation source in the scene; wherein L i represents the radiation luminance of the i-th radiation source in the scene, i represents the radiation source number, 1≤i≤N and i is an integer, N represents the total number of radiation sources in the scene, N≥1 and N is an integer;

[0011] S4, calculating the opening angle Ω i of the radiation source to the reflection point; wherein Ω i represents the opening angle of the i-th radiation source to the reflection point in the scene;

[0012] S5, calculating the total reflected radiation luminance: based on the reflected light radiation luminance L0 and the radiation luminance L i , calculating the total reflected radiation luminance L of the reflection point; the calculation formula is:

[0013]

[0014] As a preferred technical solution, the radiation source at least includes a solar radiation source and a high-temperature tail flame radiation source; wherein high temperature refers to a temperature of 400K or above.

[0015] As a preferred technical solution, the radiation source further includes a point radiation source and a surface radiation source.

[0016] As a preferred technical solution, in step S2, if the surface hit by the light is a mirror surface, the reflected light direction is calculated according to the reflection law, and the reflected light radiation luminance is calculated by using ray tracing; if the surface hit by the light is not a mirror surface, the reflected light direction is randomly sampled according to the reflection law, and the reflected light radiation luminance is calculated by using ray tracing.

[0017] As a preferred technical solution, in step S2, if the surface hit by the light is not a mirror surface, the method for calculating the reflected light radiation luminance by using ray tracing is:

[0018] If the randomly sampled reflected light can hit the radiation source, the reflected light direction is randomly resampled until the randomly sampled reflected light cannot hit the radiation source;

[0019] If the randomly sampled reflected light cannot hit the radiation source, the reflected light radiation luminance is calculated by using ray tracing.

[0020] As a preferred technical solution, step S4 includes the following steps:

[0021] S41, calculate the opening angle of the sun radiation source to the reflection point, the calculation formula is:

[0022]

[0023] Wherein, Ω A represents the opening angle of the sun radiation source to the reflection point, r sun represents the radius of the sun, R s-e represents the distance between the sun and the earth;

[0024] S42, calculate the opening angle of the point radiation source to the reflection point, the calculation formula is:

[0025]

[0026] Wherein, Ω B represents the opening angle of the point radiation source to the reflection point, r spot represents the radius of the point radiation source, l B represents the distance between the point radiation source and the reflection point;

[0027] S43, calculate the opening angle of the high temperature tail flame radiation source to the reflection point: use the bounding box algorithm to calculate the opening angle of the high temperature tail flame radiation source to the reflection point;

[0028] S44, calculate the opening angle of the surface radiation source to the reflection point, the calculation formula is:

[0029] Ω D =S / l D 2 ;

[0030] Wherein, Ω D represents the opening angle of the surface radiation source to the reflection point, S represents the texture area, l D represents the distance between the surface radiation source and the reflection point.

[0031] As a preferred technical scheme, in step S43, the opening angle of the high temperature tail flame radiation source to the reflection point is calculated by the following method:

[0032] S431, generate the AABB bounding box of the high temperature tail flame;

[0033] S432, according to the distance between the rectangular boundary surface of the AABB bounding box and the reflection point, divide each rectangular boundary surface into triangular mesh;

[0034] S433, find out the opening angle of all triangular mesh contained by the bounding box boundary surface directly radiated by the reflection point to the reflection point.

[0035] As a preferred technical scheme, in step S433, the opening angle of the triangular mesh to the reflection point is solved by the following method:

[0036] S4331, project the three vertices of the triangle mesh on the unit sphere with the reflection point as the center, to obtain the projection of the triangle mesh on the unit sphere, and the projection of the triangle mesh on the unit sphere is denoted as a spherical triangle;

[0037] S4332, obtain the three internal angles of the spherical triangle obtained in step S4331, and denote them as alpha, beta and gamma respectively;

[0038] S4333, the angular calculation formula of the triangle mesh to the reflection point is:

[0039] Ω C = alpha + beta + gamma - pi;

[0040] Wherein, Ω C represents the angular of the high-temperature tail flame radiation source to the reflection point.

[0041] As a preferred technical solution, step S1 comprises the following steps:

[0042] S11, initializing the sun radiation source: collecting and recording the azimuth of the sun radiation source;

[0043] S12, initializing the point radiation source: collecting and recording the position and brightness of the point radiation source;

[0044] S13, initializing the high-temperature tail flame radiation source: collecting and recording the range of the tail flame area;

[0045] S14, initializing the surface radiation source: collecting and recording the temperature and position of the surface radiation source.

[0046] A multi-radiation source ray tracing method comprises the following steps: obtaining the total reflected radiation brightness of the multi-radiation source; wherein in the step of obtaining the total reflected radiation brightness of the multi-radiation source, the multi-radiation source total reflected radiation brightness obtaining method is used.

[0047] Compared with the prior art, the present application has the following beneficial effects:

[0048] (1) In the present application, when calculating the weight of each radiation source in reflected light, simple geometric shapes are combined to abstract and model the radiation source, thereby eliminating the imaging process of single radiation source and saving a large amount of calculation;

[0049] (2) In the present application, the random sampling algorithm based on weight is abandoned, and a certain number of rays are sampled for each radiation source, and then the radiation brightness of the sampled rays is weighted by using the weight, so that the number of sampled rays for achieving the same accuracy of the calculation result is necessarily less than that of the complete random sampling method;

[0050] (3) The application also performs corresponding technical processing on the identification of the radiation source and the calculation of the radiation brightness, and has higher environmental adaptability compared with the visible light radiation source processing. BRIEF DESCRIPTION OF DRAWINGS

[0051] Figure 1 A step schematic diagram of a total reflected radiation brightness calculation method of a multi-radiation source according to the application;

[0052] Figure 2 A flowchart of a total reflected radiation brightness calculation method of a multi-radiation source according to the embodiment 2 of the application;

[0053] Figure 3 A schematic diagram of a solid angle calculation method for a spatial triangle to a specified point;

[0054] Figure 4 A schematic diagram of a triangle mesh division method for a solid angle of a plume radiation source to a specified point based on a plume AABB bounding box. DETAILED DESCRIPTION

[0055] The application will be further described in detail below with reference to the embodiments and the drawings, but the implementation manner of the application is not limited to this.

[0056] Embodiment 1

[0057] As shown in the figure, a total reflected radiation brightness calculation method of a multi-radiation source comprises the following steps: Figures 1 to 4

[0058] S1, initializing the radiation source: collecting the self information of all the radiation sources in the scene;

[0059] S2, calculating the reflected light radiation brightness: calculating the reflected light radiation brightness L0 according to the reflection law;

[0060] S3, calculating the radiation source radiation brightness: calculating the radiation brightness Li of each radiation source in the scene; i ; wherein Li represents the radiation brightness of the i th radiation source in the scene, i represents the radiation source number, 1≤i≤N and i is an integer, N represents the total number of the radiation sources in the scene, N≥1 and N is an integer; i

[0061] S4, calculating the opening angle Ωi of the radiation source to the reflection point; i i ; wherein Ωi represents the opening angle of the i th radiation source to the reflection point in the scene;

[0062] S5, calculating the total reflected radiation brightness: based on the reflected light radiation brightness L0 and the radiation source radiation brightness Li, calculating the total reflected radiation brightness L of the reflection point; the calculation formula is: i ​​​​

[0063]

[0064] Compared with the best technical solution at present, the present application has at least two improvements, which can improve the calculation efficiency on the premise of ensuring the calculation accuracy. First, in the process of calculating the weight of each radiation source on the reflected light, the present application abstracts and models the radiation source by using the combination of simple geometric shapes, which eliminates the process of single radiation source imaging and image processing, and saves a lot of calculation amount. Second, in the process of sampling the reflected light, the present application discards the random sampling algorithm based on weight, but samples a certain number of light lines for each radiation source, and then weights the radiation brightness of the sampled light lines by using the weight. In this way, the number of sampled light lines for achieving the same calculation result is definitely less than that of the complete random sampling method. At the same time, the present application focuses on the calculation of the infrared band, so corresponding technical processing is also carried out on the identification of the radiation source and the calculation of the radiation brightness, and the present application has higher environmental adaptability compared with the visible light radiation source processing.

[0065] As a preferred technical solution, the radiation source at least includes a solar radiation source and a high-temperature tail flame radiation source; wherein the high temperature refers to a temperature of 400K or higher.

[0066] As a preferred technical solution, the radiation source further includes a point radiation source and a surface radiation source.

[0067] The above technical solution makes the present application applicable to more application scenarios.

[0068] As a preferred technical solution, in step S2, if the surface hit by the light line is a mirror surface, the direction of the reflected light line is calculated according to the reflection law, and the radiation brightness of the reflected light line is calculated by using ray tracing; if the surface hit by the light line is not a mirror surface, the direction of the reflected light line is randomly sampled according to the reflection law, and the radiation brightness of the reflected light line is calculated by using ray tracing.

[0069] As a preferred technical solution, in step S2, if the surface hit by the light line is not a mirror surface, the method for calculating the radiation brightness of the reflected light line by using ray tracing is as follows:

[0070] If the randomly sampled reflected light line can hit the radiation source, the direction of the reflected light line is randomly sampled again until the randomly sampled reflected light line cannot hit the radiation source;

[0071] If the randomly sampled reflected light line cannot hit the radiation source, the radiation brightness of the reflected light line is calculated by using ray tracing.

[0072] The above technical solution further describes the method for calculating the radiation brightness of the reflected light line in detail.

[0073] As a preferred technical solution, step S4 includes the following steps:

[0074] S41, calculate the opening angle of the sun radiation source to the reflection point, and the calculation formula is:

[0075]

[0076] wherein, Ω A represents the opening angle of the sun radiation source to the reflection point, r sun represents the sun radius, R s-e represents the distance between the sun and the earth;

[0077] S42, calculate the opening angle of the point radiation source to the reflection point, and the calculation formula is:

[0078]

[0079] wherein, Ω B represents the opening angle of the point radiation source to the reflection point, r spot represents the radius of the point radiation source, l B represents the distance between the point radiation source and the reflection point;

[0080] S43, calculate the opening angle of the high-temperature tail flame radiation source to the reflection point: use the bounding box algorithm to calculate the opening angle of the high-temperature tail flame radiation source to the reflection point;

[0081] S44, calculate the opening angle of the surface radiation source to the reflection point, and the calculation formula is:

[0082] Ω D =S / l D 2 ;

[0083] wherein, Ω D represents the opening angle of the surface radiation source to the reflection point, S represents the texture area, l D represents the distance between the surface radiation source and the reflection point.

[0084] As a preferred technical solution, in step S43, the opening angle of the high-temperature tail flame radiation source to the reflection point is calculated by the following method:

[0085] S431, generate the AABB bounding box of the high-temperature tail flame;

[0086] S432, according to the distance between the rectangular boundary surface of the AABB bounding box and the reflection point, divide each rectangular boundary surface into a triangular mesh;

[0087] S433, find out the opening angle of all the triangular meshes contained in the bounding box boundary surface directly radiated by the reflection point to the reflection point.

[0088] As a preferred technical solution, in step S433, the opening angle of the triangular mesh to the reflection point is solved by the following method:

[0089] S4331, projecting three vertices of the triangular mesh on a unit sphere with the reflection point as the center of the sphere to obtain a projection of the triangular mesh on the unit sphere, and the projection of the triangular mesh on the unit sphere is denoted as a spherical triangle;

[0090] S4332, obtaining three internal angles of the spherical triangle obtained in step S4331, and denoting the three internal angles as α, β and γ respectively;

[0091] S4333, the calculation formula of the opening angle of the triangular mesh to the reflection point is Ω C = α + β + γ - π.

[0092] Wherein, Ω C represents the opening angle of the high-temperature exhaust plume radiation source to the reflection point.

[0093] The above technical solution further describes the method for calculating the opening angle of the radiation source to the reflection point.

[0094] As a preferred technical solution, step S1 comprises the following steps:

[0095] S11, initializing the solar radiation source: collecting and recording the azimuth of the solar radiation source;

[0096] S12, initializing the point radiation source: collecting and recording the position and brightness of the point radiation source;

[0097] S13, initializing the high-temperature exhaust plume radiation source: collecting and recording the range of the exhaust plume area;

[0098] S14, initializing the surface radiation source: collecting and recording the temperature and position of the surface radiation source.

[0099] The above technical solution further describes the method for initializing the radiation source.

[0100] A multi-radiation source ray tracing method comprises the following steps: obtaining total reflected radiation brightness of the multi-radiation source; wherein in the step of obtaining the total reflected radiation brightness of the multi-radiation source, the multi-radiation source total reflected radiation brightness obtaining method is used.

[0101] The application also provides a multi-radiation source ray tracing method using the multi-radiation source total reflected radiation brightness obtaining method.

[0102] Embodiment 2

[0103] It should be noted that in this embodiment, the radiation source used is an infrared light source, but the use of this light source in this embodiment does not mean a limitation of the application. The application can be applied to other radiation source cases as long as the electromagnetic wave generated by the radiation source propagates along a straight line.

[0104] AsFigures 1 to 4 As a further optimization of Example 1, on the basis of Example 1, the present example further comprises the following technical features:

[0105] The present application comprises the following steps:

[0106] S1, initializing all infrared radiation sources in the scene: collecting self-information of all radiation sources in the scene; specifically including:

[0107] S11, initializing a solar radiation source, which is characterized in that, for the scene, its infrared radiation can be regarded as parallel light, and meanwhile, the sun is a Lambert body, and the radiation brightness of the entire solar disc to the scene is the same. When sampling this kind of radiation source, parallel light can be directly selected, and the opening angle of the solar disc to the earth is selected as the corresponding solid angle of the radiation source (the opening angle of the solar disc to the earth is the solid angle of the solar disc to the earth). The position of the solar radiation source is collected and recorded.

[0108] S12, initializing a point radiation source, a typical representative of which is a decoy bomb, which only needs to be given its position and radiation brightness, and meanwhile, this kind of radiation source needs to be regarded as a rigid small ball in physics, and the corresponding solid angle is calculated by specifying its radius. The position and brightness of the point radiation source are collected and recorded.

[0109] S13, initializing a high-temperature plume radiation source, which is characterized in that it is related to the combustion characteristics and working conditions of an aero-engine, and usually presents a slender circular truncated cone shape, so the range of the plume region is outlined based on a clear determination rule by comparing each physical field of each grid in the entire plume region, and the solid angle of the plume to the reflection point is calculated by calculating the bounding box of the plume. The range of the plume region is collected and recorded.

[0110] S14, initializing a surface radiation source, a typical representative of which is a special effect such as a flame or explosion realized by generating a two-dimensional texture, and the radiation brightness of this kind of radiation source is determined by the temperature and the texture together, and then the solid angle to the reflection point is calculated by the position of the texture mapping in the scene. The temperature and position of the surface radiation source are collected and recorded.

[0111] After steps S11-S14, the light rays are sampled to each radiation source.

[0112] It is worth noting that steps S11-S14 are a description of the initialization of various infrared radiation sources, which is not limited to the order of steps listed in the present example. In fact, steps S11-S14 can be performed in any order, and can also be performed simultaneously.

[0113] S2, calculating the radiation brightness of the reflected light: according to the law of reflection, the radiation brightness L0 of the reflected light is calculated;

[0114] If the surface hit by the ray is a mirror surface, the direction of the reflected ray is calculated according to the law of reflection of light, and the radiance of the reflected ray is calculated by ray tracing.

[0115] If the surface hit by the ray is not a mirror surface, the direction of the reflected ray is randomly sampled according to the law of reflection. If the reflected ray hits the radiation source, the step of randomly sampling the direction of the reflected ray is re-executed; if the reflected ray does not hit the radiation source, the radiance of the reflected ray is calculated by ray tracing.

[0116] S3, calculating the radiance of the radiation source: calculating the radiance L of each radiation source in the scene i .

[0117] S4, calculating the solid angle Ω of the radiation source to the reflection point i ;

[0118] S41, calculating the solid angle of the sun radiation source to the reflection point, the calculation formula is:

[0119]

[0120] wherein Ω A represents the solid angle of the sun radiation source to the reflection point, r sun represents the radius of the sun, R s-e represents the distance from the earth to the sun;

[0121] S42, calculating the solid angle of the point radiation source to the reflection point, the calculation formula is:

[0122]

[0123] wherein Ω B represents the solid angle of the point radiation source to the reflection point, r spot represents the radius of the point radiation source, l B represents the distance from the point radiation source to the reflection point;

[0124] S43, calculating the solid angle of the high-temperature plume radiation source to the reflection point: calculating the solid angle of the high-temperature plume radiation source to the reflection point by using the bounding box algorithm;

[0125] More specifically, the method comprises the following steps:

[0126] First, an AABB bounding box (AABB bounding box refers to an axis-aligned bounding box, also known as a rectangular box, English full name is Axis Aligned Bounding Box) of the high-temperature plume is generated;

[0127] The rectangular boundary of the bounding box is adaptively divided into triangular meshes according to the distance between the reflection point and the rectangular boundary (preferably, the size of each triangular mesh is the same, and the triangular mesh is a right triangle, which is more convenient for calculation). There are at most three bounding box boundary surfaces that can be observed by the reflection point, and the solid angle of all the small triangular meshes contained in the three bounding box boundary surfaces is calculated.

[0128] The solid angle of the triangular mesh with respect to the reflection point is calculated by the following method: 1) projecting the three vertices of the triangular mesh on the unit sphere with the reflection point as the center; 2) calculating the three internal angles of the spherical triangle obtained in 1), and denoting them as α, β, and γ; and 3) the solid angle of the triangular mesh with respect to the reflection point is

[0129] Ω C = α + β + γ - π.

[0130] Figure 3 A method for calculating the solid angle of a spatial triangular surface element △ABC with respect to a point O is described. A unit sphere is made with the point O as the center, and the intersection points of AO, BO, and CO with the surface of the unit sphere are denoted as D, E, and F. A spherical triangle DEF is obtained, and the three internal angles of the spherical triangle DEF are denoted as α, β, and γ. Then the solid angle of the triangular surface element △ABC with respect to the point O is

[0131] Ω C = α + β + γ - π.

[0132] Figure 4 A triangular surface element division of an AABB bounding box (that is, the rectangular box in the figure) covering the plume region is described. A sampling light ray is emitted from the center of each triangular surface element (for example, 10 surface elements are shown in the figure), and the overall radiation brightness of the light source is calculated.

[0133] In S44, the solid angle of the surface radiation source with respect to the reflection point is calculated, and the calculation formula is:

[0134] Ω D = S / l D 2 ;

[0135] Wherein, Ω D represents the solid angle of the surface radiation source with respect to the reflection point, S represents the texture area, and l D represents the distance from the surface radiation source to the reflection point.

[0136] In S5, the total reflected radiation brightness of the reflection point is calculated.

[0137] Suppose that there are N strong radiation sources in the scene. From the reflection point, the solid angle of each radiation source with respect to the reflection point is calculated, and the solid angle of the i-th radiation source with respect to the reflection point is denoted as Ω i, the radiation luminance of the reflection point to the radiation source is calculated as L i The radiation luminance of the reflection light not radiating to the radiation source is L0, and the total radiation luminance L can be calculated as follows:

[0138]

[0139] If the intensity of the corresponding solid angle of a certain radiation source is also greatly uneven, the solid angle corresponding to the radiation source can be further subdivided, and each small solid angle can be sampled, and finally the results of all small solid angles are superimposed.

[0140] If the reflection types other than the specular reflection and diffuse reflection at the reflection point are considered during calculation, such as the BRDF (BRDF, the full name of English is Bidirectional Reflectance Distribution Function, which represents the bidirectional reflectance distribution function) reflection type, to support anisotropic reflection material, the direction of the reflected light is first determined randomly using the BRDF parameters of the material in the random sampling of the reflected light direction. At the same time, after calculating the radiation luminance of the light sampled to the radiation source, the possibility factor of the light reflected to this direction is calculated based on the BRDF parameters, which will be weighted with the solid angle of the reflection point to the radiation source to the radiation luminance of the light. The total reflected radiation luminance of the BRDF material can be obtained by the above, and the simulation of the infrared characteristics of the scene based on the inverse Monte Carlo method light tracing algorithm is realized.

[0141] The present application is suitable for simulating the illumination effect of various radiation sources on other targets in a complex scene.

[0142] The present application is suitable for calculating the shape and luminance of the special-shaped shadow formed by the non-parallel radiation source (sun) in the scene.

[0143] Compared with the best technical solution at present, the present application has at least two improvements, which can improve the calculation efficiency on the premise of ensuring the calculation accuracy. First, the present application abstracts and models the radiation source by using the combination of simple geometric shapes when calculating the weight of each radiation source in the reflected light, which eliminates the imaging of single radiation source and image processing process, and saves a lot of calculation amount. Second, the present application discards the random sampling algorithm based on weight when sampling the reflected light, and determines the number of light for each radiation source, and then uses the weight to weight the radiation luminance of the sampled light, so that the number of sampled light for the same accuracy calculation result must be less than that of the complete random sampling method. At the same time, the present application focuses on the calculation of the infrared band, so the corresponding technical treatment is also carried out on the identification of the radiation source and the calculation of the radiation luminance, and the environmental adaptability is higher than that of the visible light radiation source.

[0144] As described above, the present application can be preferably implemented.

[0145] All features disclosed in this specification, and / or all methods or processes specified in this specification can be combined in any combination, and / or substituted, except for mutually exclusive combinations of features and / or processes. All method steps disclosed in this specification can be carried out in any order, unless otherwise specified or unless it is obvious from the context that an order is necessary for the method to work. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The present application contemplates any and all combinations of the features described herein.

[0146] The above description is only the preferred embodiment of the present application, not any form of limitation to the present application. Any simple modification, equivalent replacement and improvement of the above embodiment, etc. made according to the technical essence of the present application, within the spirit and principle of the present application, all still belong to the protection scope of the technical scheme of the present application.

Claims

1. A method for determining the total reflected radiance of multiple radiation sources, characterized in that, The method comprises the following steps: S1, initializing a radiation source: collecting self-information of all radiation sources in a scene; S2, calculating reflected light radiation brightness: calculating reflected light radiation brightness L0 according to the reflection law; S3, calculating radiance of the radiation source: calculating radiance L of each radiation source in the scene i ; wherein L i represents the radiance of the i-th radiation source in the scene, i represents the radiation source number, 1≤i≤N and i is an integer, N represents the total number of radiation sources in the scene, N≥1 and N is an integer; S4, calculating the opening angle Ω of the radiation source pair to the reflection point i ; wherein Ω i denotes the opening angle of the i-th radiation source pair to the reflection point in the scene; S5, obtaining total reflected radiation luminance: based on reflected light radiation luminance L0 and radiation source radiation luminance L i , obtaining reflected point total reflected radiation luminance L; the formula is:

2. The method according to claim 1, wherein, The radiation sources at least include a sun radiation source, a high-temperature tail flame radiation source; wherein the high temperature refers to a temperature of 400K or above.

3. The method according to claim 2, wherein, The radiation sources further include a point radiation source and a surface radiation source.

4. The method according to claim 3, wherein, In step S2, if the surface hit by the light is a mirror surface, the reflected light direction is calculated according to the reflection law, and the reflected light radiation brightness is calculated by using ray tracing; if the surface hit by the light is not a mirror surface, the reflected light direction is randomly sampled according to the reflection law, and the reflected light radiation brightness is calculated by using ray tracing.

5. The method for determining the total reflected radiance of multiple radiation sources according to claim 4, characterized in that, In step S2, if the surface hit by the light is not a mirror surface, the method for calculating the reflected light radiation brightness by using ray tracing is as follows: If the randomly sampled reflected light can hit the radiation source, the reflected light direction is randomly resampled until the randomly sampled reflected light cannot hit the radiation source; If the randomly sampled reflected light cannot hit the radiation source, the reflected light radiation brightness is calculated by using ray tracing.

6. The method according to claim 5, wherein, Step S4 comprises the following steps: S41, calculating the opening angle of the sun radiation source to the reflection point, and the calculation formula is: where Ω A denotes the solar radius, R sun denotes the solar radius, R s-e denotes the solar radius, R S42, calculating the opening angle of the point radiation source to the reflection point, and the calculation formula is: where Ω B represents the opening angle of the point radiation source to the reflection point, r spot represents the radius of the point radiation source, l B represents the distance from the point radiation source to the reflection point; S43, calculating the opening angle of the high-temperature tail flame radiation source to the reflection point: calculating the opening angle of the high-temperature tail flame radiation source to the reflection point by using the bounding box algorithm; S44, calculating the opening angle of the surface radiation source to the reflection point, and the calculation formula is: Ω D = S / l D 2 ; wherein Ω D represents the solid angle of the surface radiation source to the reflection point, S represents the texture area, and l D represents the distance from the surface radiation source to the reflection point.

7. A method according to claim 6, characterized in that In step S43, the opening angle of the high-temperature tail flame radiation source to the reflection point is calculated by using the following method: S431, generating an AABB bounding box of the high-temperature tail flame; S432, according to the distance between the rectangular boundary surface of the AABB bounding box and the reflection point, each rectangular boundary surface is divided into a triangular mesh; S433, the opening angle of all triangular meshes contained by the bounding box boundary surface directly radiated by the reflection point to the reflection point is calculated.

8. The method according to claim 7, wherein, In step S433, the opening angle of the triangular mesh to the reflection point is calculated by using the following method: S4331, projecting the three vertices of the triangular mesh on the unit sphere with the reflection point as the center to obtain the projection of the triangular mesh on the unit sphere, and the projection of the triangular mesh on the unit sphere is denoted as a spherical triangle; S4332, calculating the three internal angles of the spherical triangle obtained in step S4331, and denoted as α, β and γ respectively; S4333, the calculation formula of the opening angle of the triangular mesh to the reflection point is: Ω C = a + b + g - p; where Ω C represents the opening angle of the high-temperature plume radiation source to the reflection point.

9. A method according to any one of claims 3 to 8, characterized in that, Step S1 comprises the following steps: S11, initializing the sun radiation source: collecting and recording the position of the sun radiation source; S12, initializing the point radiation source: collecting and recording the position and brightness of the point radiation source; S13, initializing the high-temperature tail flame radiation source: collecting and recording the range of the tail flame area; S14, initializing the surface radiation source: collecting and recording the temperature and position of the surface radiation source.

10. A multi-radiosity ray tracing method, characterized by, The method comprises the following steps: The total reflected radiation brightness of the multiple radiation sources is calculated; wherein in the step of calculating the total reflected radiation brightness of the multiple radiation sources, the total reflected radiation brightness calculation method of the multiple radiation sources is used.

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