Atmospheric background radiation modeling simulation method and device for air optical detection

Abstract

The invention discloses an atmospheric background radiation modeling simulation method and device for air optical detection, and belongs to the field of optical simulation. The method comprises the following steps: determining whether a detection scene is a cloud scene or not according to whether the detection scene has a cloud layer or not; if yes, generating a target three-dimensional cloud field by adopting a particle system; according to the initial environment parameters, respectively establishing a first lookup table of the radiance of the clear sky scene about the detector height and the pixel line-of-sight zenith angle, and establishing a second lookup table of the radiance and the transmittance of each segment path of the cloud scene about the detector height and the detection line-of-sight zenith angle; determining air data in all the detected pixel data according to the periodic height and the visual geometric information of the detector; and searching a lookup table of a corresponding scene according to the air data, and determining a radiance value used for generating a radiance image in front of a mouth. According to the invention, complex air optical visual simulation can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field of optical simulation, and in particular to a method and device for modeling and simulating atmospheric background radiation for air optical detection. Background Art

[0002] In semi-physical and fully digital optical scene simulations, airborne detection images are primarily influenced by optical signals generated by the atmosphere and its clouds. Therefore, a model specifically representing the atmospheric optical background is required to provide background image simulation data. Currently, optical scene simulation primarily utilizes computer graphics engines to simulate visual scenes. These simulations primarily target full-color scenes perceived by human vision and physical scenes on land and sea surfaces.

[0003] In related technologies, in special optical scene simulation tasks such as detection payload selection and design, performance evaluation, etc., it is necessary to generate quantitative radiation brightness images of any specified spectral band. At the same time, the cross-magnitude changes in radiation brightness in air detection with detection angle, detection altitude and spectral band are all impossible to achieve with current ordinary visual simulation.

[0004] Based on this, there is an urgent need for a method and device for modeling and simulating atmospheric background radiation for air optical detection to solve the above technical problems. Summary of the Invention

[0005] The present invention provides a method and device for modeling and simulating atmospheric background radiation for airborne optical detection, which can solve the problem that related technologies are difficult to achieve in complex visual scene simulation. The technical solution is as follows:

[0006] In one aspect, a method for modeling and simulating atmospheric background radiation for airborne optical detection is provided, the method comprising:

[0007] Determine whether the detection scene is a cloudy scene according to whether there is cloud layer in the detection scene; if so, use the particle system to generate the target three-dimensional cloud field;

[0008] Based on the initial environmental parameters, a first lookup table is established for the radiance of the clear sky scene in relation to the detector height and the pixel line of sight zenith angle, and a second lookup table is established for the radiance and transmittance of each segmented path in the cloudy scene in relation to the detector height and the detection line of sight zenith angle;

[0009] Determine the air data in all detected pixel data based on the periodic height and viewing direction geometry information of the detector;

[0010] A lookup table of a corresponding scene is searched according to the air data to determine a radiance value for generating a radiance image in front of the mouth.

[0011] On the other hand, a device for modeling and simulating atmospheric background radiation for air optical detection is provided, the device comprising:

[0012] A first determination module is configured to determine whether the detection scene is a cloudy scene according to whether there is a cloud layer in the detection scene; if so, generate a target three-dimensional cloud field using a particle system;

[0013] A modeling module is used to establish a first lookup table of the radiance of a clear sky scene with respect to the detector height and the pixel line of sight zenith angle, and to establish a second lookup table of the radiance and transmittance of each segmented path of a cloudy scene with respect to the detector height and the detection line of sight zenith angle, based on the initial environmental parameters;

[0014] The second determination module is used to determine the air data in all the detected pixel data according to the periodic height and viewing direction geometric information of the detector;

[0015] The third determining module is used to search a lookup table of a corresponding scene according to the air data, and determine a radiation brightness value for generating a radiation brightness image in front of the mouth.

[0016] On the other hand, a computer device is provided, which includes a memory and a processor, wherein the memory is used to store computer programs, and the processor is used to execute the computer programs stored in the memory to implement the steps of the above-mentioned atmospheric background radiation modeling and simulation method for air optical detection.

[0017] On the other hand, a computer-readable storage medium is provided, in which a computer program is stored. When the computer program is executed by a processor, the steps of the atmospheric background radiation modeling and simulation method for air optical detection are implemented.

[0018] On the other hand, a computer program product is provided, comprising a computer program, which, when executed by a processor, implements the steps of the above-mentioned method for modeling and simulating atmospheric background radiation for air optical detection.

[0019] The technical solution provided by the present invention can at least bring about the following beneficial effects: computational models for rapidly generating radiation images in front of the aperture of an optical detector are constructed for clear-sky atmospheres and cloudy atmospheres, respectively. The direct radiation transfer calculation method is used for clear-sky atmospheres, while the cloud-gas radiation decoupling method is used for cloudy atmospheres. Furthermore, based on the pre-calculation of a lookup table for the atmospheric radiation model, a reconstruction algorithm for atmospheric radiation in front of the aperture embedded in an open-source graphics engine is utilized to rapidly simulate the atmospheric background radiation brightness image. This method can simulate and calculate in real time the radiation brightness image in front of the aperture of an optical detector during air detection, and its changes with geometric parameters such as detection altitude, line-of-sight azimuth, and line-of-sight elevation angle, providing atmospheric background model support for full-digital and semi-physical simulations of air optical detection scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 This is a flow chart of a method for modeling and simulating atmospheric background radiation for air optical detection provided by one embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of air detection under clear sky conditions provided by an embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of air detection under cloudy conditions provided by an embodiment of the present invention;

[0024] Figure 4 This is a structural diagram of an atmospheric background radiation modeling and simulation device for air optical detection provided by one embodiment of the present invention;

[0025] Figure 5 This is a hardware architecture diagram of a computer device provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0027] As mentioned above, ordinary visual simulation cannot represent the cross-magnitude changes in radiation brightness during air detection due to detection angle, detection altitude, and spectrum.

[0028] Based on this, the concept of the present invention is to construct a computational model for the rapid generation of radiation images in front of the optical detector aperture for clear sky atmosphere and cloudy atmosphere respectively, so as to simulate and calculate in real time the radiation brightness image in front of the optical detector aperture during air detection and its changes with geometric parameters such as detection altitude, line of sight azimuth, and line of sight pitch angle.

[0029] The specific implementation of the above concept is described below.

[0030] Please refer to Figure 1 An embodiment of the present invention provides a method for modeling and simulating atmospheric background radiation for air optical detection, the method comprising:

[0031] Step 100, determining whether the detection scene is a cloudy scene according to whether there is a cloud layer in the detection scene; if so, generating a target three-dimensional cloud field using a particle system;

[0032] Step 102: Based on the initial environmental parameters, a first lookup table is established for the radiance of a clear sky scene in relation to the detector height and the pixel line of sight zenith angle, and a second lookup table is established for the radiance and transmittance of each segmented path in a cloudy scene in relation to the detector height and the detection line of sight zenith angle.

[0033] Step 104, determining the air data in all detected pixel data based on the periodic height and viewing direction geometry information of the detector;

[0034] Step 106 : searching a lookup table corresponding to the scene according to the air data to determine a radiance value for generating a radiance image in front of the mouth.

[0035] In an embodiment of the present invention, computational models for rapidly generating radiation images in front of the aperture of an optical detector are constructed for clear-sky and cloudy atmospheres, respectively. The direct radiation transfer method is used for clear-sky atmospheres, while the cloud-gas radiation decoupling method is used for cloudy atmospheres. Furthermore, based on the pre-calculation of a lookup table for the atmospheric radiation model, a reconstruction algorithm for atmospheric radiation in front of the aperture embedded in an open-source graphics engine is utilized to rapidly simulate the atmospheric background radiation brightness image. This method can simulate and calculate the radiation brightness image in front of the aperture of an optical detector during air detection in real time, as well as its changes with geometric parameters such as detection altitude, line-of-sight azimuth, and line-of-sight elevation angle. This provides atmospheric background model support for both full-digital and hardware-in-the-loop simulations of air optical detection scenarios.

[0036] Described below Figure 1 How to perform the steps shown.

[0037] First, for step 100, whether the detection scene is a cloudy scene is determined based on whether there is a cloud layer in the detection scene; if so, a particle system is used to generate a target three-dimensional cloud field.

[0038] The background radiation of the air optical detection scene described in the embodiment of the present invention mainly refers to the background generated by atmospheric gas radiation and cloud radiation, which are the main background objects encountered by air optical detection. Therefore, it is necessary to construct a calculation method for the air background radiation brightness according to clear sky and cloudy scenes respectively. Correspondingly, before calculation, it is necessary to first determine whether it is a clear sky scene or a cloudy scene; if it is a cloudy scene, a particle system is used to generate a target three-dimensional cloud field of a specified height and type.

[0039] Then, for step 102, based on the initial environmental parameters, a first lookup table is established for the radiant brightness of the clear sky scene with respect to the detector height and the pixel line of sight zenith angle, and a second lookup table is established for the radiant brightness and transmittance of each segmented path of the cloudy scene with respect to the detector height and the detection line of sight zenith angle.

[0040] In the embodiment of the present invention, when the detector is detecting the sky under clear sky conditions, the background radiation received by a single pixel mainly comes from the radiation of the atmospheric gas itself and the scattered radiation of the sun / moon on the detection line of sight path, which are accumulated in front of the detector mouth after being transmitted. Figure 2 Therefore, the calculation formula for the radiant brightness of the atmospheric background in a clear sky scene is expressed as:

[0041]

[0042] Where L represents the radiation brightness received in front of the detector aperture; ν1 and ν2 represent the starting and ending wavenumbers of the detector spectrum, respectively; H represents the detector height; θ represents the zenith angle of the line of sight at the detector, with the local zenith direction as the positive direction, θ = 0 for vertical upward line of sight, and θ = 180 for vertical downward line of sight; represents the sight azimuth; s0 represents the starting point of the sight, that is, the location of the detector; s t represents the end point of the line of sight, i.e., the intersection of the detector and the top of the atmosphere; J(s) represents the source function at point s on the line of sight; k(s) represents the extinction coefficient at point s; and τ(s,s0) represents the atmospheric optical depth along the path between s and s0. These parameters are calculated at different altitudes using low- and mid-to-high-atmosphere radiative transfer software, and then integrated according to the formula to obtain the total radiance.

[0043] Here, a one-dimensional spherical atmospheric model is constructed to calculate the line-of-sight geometry. The above radiation transfer integral is converted into the accumulation of parameters along the path. The calculation formula for the line-of-sight transmission length in each homogeneous layer can be expressed as:

[0044]

[0045] Among them, s i is the line-of-sight transmission length in the i-th homogeneous atmosphere; R is the radius of the earth; H i is the upper boundary height of the i-th homogeneous atmospheric layer, H i-1 is the lower boundary height of the i-th homogeneous atmospheric layer; θ i To detect the line of sight at H i The zenith angle at the height can be expressed as:

[0046]

[0047] According to the above calculation formula, the radiance corresponding to each detector height and pixel line of sight zenith angle in a clear sky scene can be calculated, and a first lookup table can be established based on these data.

[0048] Furthermore, a model for the variation of the radiance and transmittance of each segmented path in a cloud scene with respect to the detector height and the detection line of sight zenith angle is established, including:

[0049] Segmented path radiation brightness change model:

[0050]

[0051] Among them, L n represents the radiant brightness of the nth atmospheric path; s1 represents the starting position of the path, and s2 represents the ending position of the path; J n (s) represents the source function at position s on the nth path; k n (s) represents the extinction coefficient at point s on the nth path;

[0052] Transmittance change model:

[0053] T n =exp[-τ n (s1,s2)]

[0054] Among them, T n represents the atmospheric transmittance of the nth segment; τ n (s, s1) represents the atmospheric optical thickness between s and s1 on the nth path.

[0055] According to the segmented path radiance change model, the radiance corresponding to each detector height and pixel line of sight zenith angle in a cloudy scene is calculated. According to the transmittance change model, the transmittance corresponding to each detector height and pixel line of sight zenith angle in a cloudy scene is calculated, and a second lookup table containing the radiance and the transmittance is established.

[0056] It is worth noting that the calculation of the above-mentioned clear sky background radiation, path radiation and transmittance all take several minutes. In order to achieve the ability to generate atmospheric background radiation brightness images in real time, the embodiment of the present invention adopts pre-processing calculation for the above-mentioned calculation process, that is, according to the above-mentioned model, the data corresponding to each detector height and pixel line of sight zenith angle are calculated, and a corresponding data set lookup table is established, thereby providing a data basis for subsequent radiation image generation.

[0057] With respect to step 104 , the air data in all the detected pixel data are determined based on the periodic height and viewing direction geometric information of the detector.

[0058] In the embodiment of the present invention, the air data is determined in the following manner: in the graphics engine, based on the periodic height and viewing direction geometry information of the detector, the line of sight is judged pixel by pixel to determine whether it is an air detection. The judgment criterion is: when the line of sight zenith angle θ≤θ t When , the pixel data is determined to be air detection data; where θ t is the critical zenith angle where the line of sight is tangent to the Earth’s surface, calculated using the following formula:

[0059]

[0060] Where, R is the radius of the Earth; H is the height of the detector;

[0061] When the line of sight zenith angle θ>θ t , it is determined that the pixel data is ground detection data and a null value is assigned to the data.

[0062] With respect to step 106 , based on the acquired detection data, a lookup table corresponding to the scene is searched according to the air data to obtain a radiance value for generating a radiance image in front of the mouth.

[0063] The lookup table constructed by step 102 can speed up the efficiency of image generation. For clear sky scenes, since there is no interference from clouds, the first lookup table can be directly searched according to the actual detector height and the actual pixel line of sight zenith angle to obtain the corresponding radiation brightness value.

[0064] Furthermore, for cloudy scenes, since clouds do not cover the entire sky, there are still situations similar to clear sky scenes in cloudy scenes. In part, the line of sight of a single pixel does not intersect with the cloud field, and its perceived background is still the clear sky background radiation. Therefore, before searching, it is necessary to determine whether the pixel data is clear sky pixel data (that is, the pixel data is not obscured by clouds) based on the spatial distribution of the three-dimensional cloud field. If so, the radiation brightness value corresponding to the clear sky pixel data is determined according to the first lookup table.

[0065] The other part is where the line of sight of a single pixel intersects the cloud field, which is considered to be cloud pixel data (that is, the pixel data is blocked by clouds). In this case, the influence of the positional relationship between the detector and the cloud layer on the radiation brightness is considered. In other words, a cloud change model needs to be established to calculate the radiation brightness before reaching the pixel port.

[0066] Specifically, first, the radiance and transmittance corresponding to the cloud pixel data are found by searching the second lookup table.

[0067] Then follow the Figure 3 The following cloud change models are established for the two cases where the detector is under the cloud and above the cloud:

[0068] The radiation brightness received by the detector under the cloud can be expressed as follows:

[0069]

[0070] in, Represents the detector's pixel pointing to the line of sight at height H below the cloud The brightness of the background radiation received at Represents the portion of atmospheric radiation from the top of the atmosphere to the height of the cloud top in the line of sight direction; Represents the cloud path radiation portion from the cloud top to the cloud base in the line of sight direction, T cd Represents the cloud transmittance of this part; represents the atmospheric radiation portion from the cloud base to the detector aperture in the line of sight direction, T ad Represents the atmospheric transmittance of this part; χ 1d , χ cd are the spectrum weighting factors after the multiplication of the two-stage radiation and transmittance spectra into integral multiplication; H t 、H b They are cloud top height and cloud base height respectively.

[0071] The radiance received by the detector above the cloud can be similarly expressed as follows:

[0072]

[0073] in, Represents the detector's pixel pointing to the line of sight at height H above the cloud The brightness of the background radiation received at Represents the portion of atmospheric radiation from the top of the atmosphere to the height of the cloud base in the line of sight direction; Represents the cloud path radiation portion from the cloud base to the cloud top in the line of sight direction, T cu Represents the cloud transmittance of this part; represents the atmospheric radiation portion from the cloud top to the detector aperture in the line of sight direction, T au Represents the atmospheric transmittance of this part; χ 1u , χ cu They are the spectral weighting factors after the multiplication of the two-stage radiation and transmittance spectra is converted into integral multiplication.

[0074] The above segmented modeling of homogeneous atmosphere and cloud radiation is primarily intended to address the efficient generation of radiation from heterogeneously distributed cloud fields, and can be extended to express the calculation of background radiation brightness for multi-layer clouds. In practice, to save time in preprocessing during the scene generation phase, the above segmented expressions are combined and simplified in the actual calculation. For the subcloud scenario, the simplified expression is:

[0075]

[0076] in, Represents the radiation part of the path from the cloud top to the detector aperture in the line of sight direction, T ac,d represents the path transmittance of this part; χ d It is the spectral weighting factor obtained by converting the combined path radiation and path transmittance spectrum into integral multiplication.

[0077] For the cloud, the simplified expression is:

[0078]

[0079] in, Represents the radiation part of the path from the cloud base to the detector aperture in the line of sight direction, T ac,u represents the path transmittance of this part; χ u It is the spectral weighting factor obtained by converting the combined path radiation and path transmittance spectrum into integral multiplication.

[0080] It is worth noting that this step is a calculation performed in the graphics engine, and all of them are simple algebraic calculations in parallel on the GPU. Therefore, it is possible to render and generate a radiation brightness image in front of the mouth in real time according to the periodic information of the detector.

[0081] Please refer to Figure 4 The embodiment of the present invention provides an atmospheric background radiation modeling and simulation device for air optical detection, the device comprising:

[0082] The first determination module 400 is configured to determine whether the detection scene is a cloudy scene according to whether there is a cloud layer in the detection scene; if so, generate a target three-dimensional cloud field using a particle system;

[0083] Modeling module 402 is used to establish a first lookup table of radiance with respect to detector height and pixel line of sight zenith angle for a clear sky scene based on the initial environmental parameters, and to establish a second lookup table of radiance and transmittance with respect to detector height and detection line of sight zenith angle for each segment path of a cloudy scene;

[0084] A second determination module 404 is configured to determine the air data in all the detected pixel data based on the periodic height and viewing direction geometry information of the detector;

[0085] The third determining module 406 is configured to search a lookup table corresponding to a scene according to the air data, and determine a radiance value for generating a radiance image in front of the mouth.

[0086] In the embodiment of the present invention, when the modeling module 402 establishes a first lookup table of the radiance of a clear sky scene with respect to the detector height and the detection line of sight zenith angle, it is specifically configured to perform the following operations:

[0087] Based on the accumulated values of atmospheric gas self-radiation and solar / lunar scattered radiation in front of the detector aperture after transmission along the detection line of sight path, a clear sky variation model of the radiation brightness with the detector height and the detection line of sight zenith angle in clear sky scenes is established:

[0088]

[0089] Where L is the radiation brightness received in front of the detector aperture; ν1 and ν2 are the starting and ending wavenumbers of the detector spectrum, respectively; H is the detector height; θ is the line of sight zenith angle at the detector; is the sight azimuth; s0 is the starting point of the sight; s t is the end point of the line of sight; J(s) is the source function at point s on the line of sight; k(s) is the extinction coefficient at point s; τ(s,s0) is the atmospheric optical thickness of the path between s and s0;

[0090] According to the clear sky variation model, the radiance corresponding to each detector height and pixel line of sight zenith angle in the clear sky scene is calculated, and the first lookup table is established.

[0091] In the embodiment of the present invention, when the modeling module 402 creates a second lookup table of the radiance and transmittance of each segmented path in a cloud scene with respect to the detector height and the detection line of sight zenith angle, it is specifically configured to perform the following operations:

[0092] Establish a segmented path radiation brightness change model:

[0093]

[0094] Among them, L n represents the radiant brightness of the nth atmospheric path; s1 represents the starting position of the path, and s2 represents the ending position of the path; J n (s) represents the source function at position s on the nth path; k n (s) represents the extinction coefficient at point s on the nth path;

[0095] Establish a transmittance change model:

[0096] T n =exp[-τ n (s1,s2)]

[0097] Among them, T n represents the atmospheric transmittance of the nth segment; τ n (s, s1) represents the atmospheric optical thickness between s and s1 on the nth path;

[0098] According to the segmented path radiance change model, the radiance corresponding to each detector height and pixel line of sight zenith angle in a cloudy scene is calculated. According to the transmittance change model, the transmittance corresponding to each detector height and pixel line of sight zenith angle in a cloudy scene is calculated, and a second lookup table containing the radiance and the transmittance is established.

[0099] In the embodiment of the present invention, the second determination module 404 determines the air data in all detected pixel data based on the periodic height and viewing direction geometric information of the detector, including:

[0100] When the line of sight zenith angle θ≤θ t When , the pixel data is determined to be air detection data; wherein, θ t is the critical zenith angle where the line of sight is tangent to the Earth’s surface, calculated using the following formula:

[0101]

[0102] Where, R is the radius of the Earth; H is the height of the detector;

[0103] When the line of sight zenith angle θ>θ t , it is determined that the pixel data is ground detection data, and a null value is assigned to the data.

[0104] In an embodiment of the present invention, when the third determination module 406 searches for a lookup table corresponding to the scene based on the sky data to obtain a radiation brightness value for generating a radiation brightness image in front of the mouth, it is specifically used to perform the following operations: when the scene is a clear sky scene, the first lookup table is searched according to the actual detector height and the actual pixel line of sight zenith angle to obtain the corresponding radiation brightness value; when the scene is a cloudy scene, whether the pixel data is clear sky pixel data is determined according to the spatial distribution of the three-dimensional cloud field. If so, the radiation brightness value corresponding to the clear sky pixel data is determined according to the first lookup table; otherwise, the corresponding process radiation brightness and transmittance are determined according to the actual detector height and the actual pixel line of sight zenith angle of the cloudy pixel data, and the determination result is input into the preset cloud change model to calculate the radiation brightness value corresponding to the cloudy pixel data.

[0105] In the embodiment of the present invention, the cloud change model is established in the following manner:

[0106] The cloud change model is established based on the positional relationship between the detector and the cloud layer. When the detector is located below the cloud layer, the cloud change model is:

[0107]

[0108] Where, The pixel pointing line of sight of the detector at the height H below the cloud The brightness of the background radiation received at It is the part of atmospheric radiation from the top of the atmosphere to the height of the cloud top in the line of sight direction; is the radiation part of the path from the cloud top to the detector aperture in the line of sight direction, T ac,d is the path transmittance of the radiation part of the path from the cloud top to the detector aperture in the line of sight direction; d is the spectrum weighting factor obtained by converting the combined path radiation and path transmittance spectrum into integral multiplication;

[0109] When the detector is located above the cloud layer, the cloud change model is:

[0110]

[0111] Where, The detector's pixel pointing line of sight at height H above the cloud The brightness of the background radiation received at It is the part of atmospheric radiation from the top of the atmosphere to the height of the cloud base in the line of sight direction; is the radiation part of the path from the cloud base to the detector aperture in the line of sight direction, T ac,u is the path transmittance of the radiation part of the path from the cloud base to the detector aperture in the line of sight direction; u It is the spectral weighting factor after the combined path radiation and path transmittance spectrum are multiplied into integral multiplication.

[0112] It should be noted that the atmospheric background radiation modeling and simulation device for air optical detection provided in the above embodiment is only illustrated by the division of the above functional modules. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. In addition, the atmospheric background radiation modeling and simulation device for air optical detection provided in the above embodiment and the atmospheric background radiation modeling and simulation method embodiment for air optical detection are of the same concept. The specific implementation process is detailed in the method embodiment and will not be repeated here.

[0113] The embodiment of the present application also provides a computer device, please refer to Figure 5 The computer device includes a processor and a memory, wherein the memory stores at least one instruction, at least one program, code set or instruction set, and the at least one instruction, at least one program, code set or instruction set is loaded and executed by the processor to implement the atmospheric background radiation modeling and simulation method for air optical detection provided by the above-mentioned method embodiments.

[0114] An embodiment of the present application also provides a computer-readable storage medium, which stores at least one instruction, at least one program, code set or instruction set, and the at least one instruction, at least one program, code set or instruction set is loaded and executed by a processor to implement the atmospheric background radiation modeling and simulation method for air optical detection provided by the above-mentioned method embodiments.

[0115] An embodiment of the present application also provides a computer program product, which includes a computer program. The processor of a computer device reads the computer program from a computer-readable storage medium, and the processor executes the computer program, so that the computer device executes the atmospheric background radiation modeling and simulation method for air optical detection described in any of the above embodiments.

[0116] For the convenience of description, the above systems or devices are described as being divided into various modules or units according to their functions. Of course, when implementing the present application, the functions of each unit can be implemented in the same or multiple software and / or hardware.

[0117] Through the description of the above embodiments, it can be seen that those skilled in the art can clearly understand that the present application can be implemented by means of software plus a necessary general hardware platform. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which can be stored in a storage medium such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in various embodiments of the present application or certain parts of the embodiments.

[0118] Finally, it should be noted that, in this document, relational terms such as first, second, third, and fourth are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

[0119] The above is only a preferred embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A method for modeling and simulating atmospheric background radiation for air optical detection, characterized in that: The method comprises: Determine whether the detection scene is a cloudy scene according to whether there is cloud layer in the detection scene; if so, use the particle system to generate the target three-dimensional cloud field; Based on the initial environmental parameters, a first lookup table is established for the radiance of the clear sky scene in relation to the detector height and the pixel line of sight zenith angle, and a second lookup table is established for the radiance and transmittance of each segmented path in the cloudy scene in relation to the detector height and the detection line of sight zenith angle; Determine the air data in all detected pixel data based on the periodic height and viewing direction geometry information of the detector; A lookup table of a corresponding scene is searched according to the air data to determine a radiance value for generating a radiance image in front of the mouth.

2. The method according to claim 1, wherein The step of establishing a first lookup table of the radiance of a clear sky scene with respect to the detector height and the detection line of sight zenith angle comprises: Based on the accumulated values of atmospheric gas self-radiation and solar / lunar scattered radiation in front of the detector aperture after transmission along the detection line of sight path, a clear sky variation model of the radiation brightness with the detector height and the detection line of sight zenith angle in clear sky scenes is established: Where L is the radiation brightness received in front of the detector aperture; ν1 and ν2 are the starting and ending wavenumbers of the detector spectrum, respectively; H is the detector height; θ is the line of sight zenith angle at the detector; is the sight azimuth; s0 is the starting position of the sight; s t is the end point of the line of sight; J(s) is the source function at point s on the line of sight; k(s) is the extinction coefficient at point s; τ(s,s0) is the atmospheric optical thickness of the path between s and s0; According to the clear sky variation model, the radiance corresponding to each detector height and pixel line of sight zenith angle in the clear sky scene is calculated, and the first lookup table is established.

3. The method according to claim 2, wherein The second lookup table of the radiance and transmittance of each segmented path in the cloud scene in relation to the detector height and the detection line of sight zenith angle is established, including: Establish a segmented path radiation brightness change model: Among them, L n represents the radiant brightness of the nth atmospheric path; s1 represents the starting position of the path, and s2 represents the ending position of the path; J n (s) represents the source function at position s on the nth path; k n (s) represents the extinction coefficient at point s on the nth path; Establish a transmittance change model: T n =exp[-τ n (s1,s2)] Among them, T n represents the atmospheric transmittance of the nth segment; τ n (s, s1) represents the atmospheric optical thickness between s and s1 on the nth path; According to the segmented path radiance change model, the radiance corresponding to each detector height and pixel line of sight zenith angle in a cloudy scene is calculated. According to the transmittance change model, the transmittance corresponding to each detector height and pixel line of sight zenith angle in a cloudy scene is calculated, and a second lookup table containing the radiance and the transmittance is established.

4. The method according to claim 1, wherein Determining the air data in all detected pixel data based on the periodic height and viewing direction geometric information of the detector includes: When the line of sight zenith angle θ≤θ t When , the pixel data is determined to be air detection data; wherein, θ t is the critical zenith angle where the line of sight is tangent to the Earth’s surface, calculated using the following formula: Where, R is the radius of the Earth; H is the height of the detector; When the line of sight zenith angle θ>θ t , it is determined that the pixel data is ground detection data, and a null value is assigned to the data.

5. The method according to claim 3, wherein The step of searching a lookup table corresponding to a scene according to the air data to obtain a radiance value for generating a radiance image in front of the mouth comprises: When the scene is a clear sky scene, the first lookup table is searched according to the actual detector height and the actual pixel line of sight zenith angle to obtain the corresponding radiance value; When the scene is a cloudy scene, determine whether the pixel data is clear sky pixel data based on the spatial distribution of the three-dimensional cloud field. If so, determine the radiation brightness value corresponding to the clear sky pixel data based on the first lookup table; otherwise, determine the corresponding radiation brightness and transmittance based on the actual detector height and the actual pixel line of sight zenith angle of the cloudy pixel data, and input the determination result into the preset cloud change model to calculate the radiation brightness value corresponding to the cloudy pixel data.

6. The method according to claim 5, wherein The cloud change model is established in the following way: The cloud change model is established based on the positional relationship between the detector and the cloud layer. When the detector is located below the cloud layer, the cloud change model is: Where, The pixel pointing line of sight of the detector at the height H below the cloud The brightness of the background radiation received at It is the part of atmospheric radiation from the top of the atmosphere to the height of the cloud top in the line of sight direction; is the radiation part of the path from the cloud top to the detector aperture in the line of sight direction, T ac,d is the path transmittance of the radiation part of the path from the cloud top to the detector aperture in the line of sight direction; d is the spectrum weighting factor obtained by converting the combined path radiation and path transmittance spectrum into integral multiplication; When the detector is located above the cloud layer, the cloud change model is: Where, The detector is pointing to the line of sight at the height H above the cloud. The brightness of the background radiation received at It is the part of atmospheric radiation from the top of the atmosphere to the height of the cloud base in the line of sight direction; is the radiation part of the path from the cloud base to the detector aperture in the line of sight direction, T ac,u is the path transmittance of the radiation part of the path from the cloud base to the detector aperture in the line of sight direction; u It is the spectral weighting factor after the combined path radiation and path transmittance spectrum are multiplied into integral multiplication.

7. A device for modeling and simulating atmospheric background radiation for air optical detection, characterized in that: The device comprises: A first determination module is configured to determine whether the detection scene is a cloudy scene according to whether there is a cloud layer in the detection scene; if so, a target three-dimensional cloud field is generated using a particle system; A modeling module is used to establish a first lookup table of the radiance of a clear sky scene with respect to the detector height and the pixel line of sight zenith angle, and to establish a second lookup table of the radiance and transmittance of each segmented path of a cloudy scene with respect to the detector height and the detection line of sight zenith angle, based on the initial environmental parameters; A second determination module is used to determine the air data in all the detected pixel data according to the periodic height and viewing direction geometric information of the detector; The third determining module is used to search a lookup table of a corresponding scene according to the air data, and determine a radiation brightness value for generating a radiation brightness image in front of the mouth.

8. A computer device, characterized in that: The computer device includes a memory and a processor, the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory to implement the steps of any one of the methods described in claims 1-6.

9. A computer-readable storage medium, characterized in that The storage medium stores a computer program, which, when executed by a processor, implements the steps of the method according to any one of claims 1 to 6.

10. A computer program product, characterized in that The method comprises a computer program, wherein when the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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