Calculation Method, Device, Terminal and Storage Medium for Radiation Spectrum out of Water

Abstract

The present invention provides a method, device, terminal and storage medium for calculating the radiance spectrum of water leaving. The method includes: calculating the sky light reflection angle corresponding to each pixel in the water body hyperspectral image captured by the hyperspectral camera obliquely according to the inclination angle and field of view angle of the hyperspectral camera; calculating the relative radiation amount of the sky light received by each pixel in the water body hyperspectral image according to the sky light reflection angle corresponding to each pixel; calculating the sky light spectrum received by each pixel in the water body hyperspectral image based on the spectra and the relative radiation amount of the sky light received at the first preset position and the second preset position where the difference in the radiance spectrum of water leaving is within a preset difference range; calculating the radiance spectrum of water leaving for each pixel in the water body hyperspectral image based on the spectrum and the sky light spectrum received by each pixel. The present invention can accurately calculate the radiance spectrum of water leaving for each pixel in the water body hyperspectral image and improve the overall signal-to-noise ratio.

Description

Technical Field

[0001] The present invention relates to the technical field of in-situ observation of water color remote sensing, and particularly relates to a method, device, terminal and storage medium for calculating the water-leaving radiance spectrum. Background Technique

[0002] Water-leaving radiance is one of the key physical quantities in in-situ observation of water color remote sensing, and the remote sensing reflectance calculated from it is the most basic parameter for water color remote sensing parameter inversion.

[0003] However, when remotely sensing and inverting hyperspectral water quality parameters of natural waters such as lakes, rivers, and seawater, the radiation received by the hyperspectral camera tilted to shoot the water surface includes not only water-leaving radiance but also skylight. As Figure 1 shown, the reflection of skylight on the far water surface (at a larger zenith angle) is significantly higher than that on the near water surface (at a smaller zenith angle), that is, the intensity of skylight on the far water surface is much higher than the water-leaving radiance. However, skylight does not contain effective information about water body substances, and only water-leaving radiance contains effective information about water body substances. Therefore, if the skylight part in the hyperspectral image of the water body is not deducted, it will greatly increase the noise ratio of the water-leaving radiance spectrum and affect subsequent data processing. Summary of the Invention

[0004] Embodiments of the present invention provide a method, device, terminal and storage medium for calculating the water-leaving radiance spectrum, so as to solve the problem that the noise ratio of the water-leaving radiance spectrum of the hyperspectral image of the water body obtained by tilting the hyperspectral camera to shoot the water surface is relatively large, which is not conducive to subsequent data processing.

[0005] In a first aspect, embodiments of the present invention provide a method for calculating the water-leaving radiance spectrum, including:

[0006] According to the tilt angle and field of view angle of the hyperspectral camera, calculate the angle of skylight received by each pixel in the hyperspectral image of the water body tilted by the hyperspectral camera, denoted as the skylight reflection angle corresponding to the pixel;

[0007] Based on the water surface reflection law and the distribution law of skylight, calculate the relative radiation amount of skylight received by each pixel in the hyperspectral image of the water body according to the skylight reflection angle corresponding to each pixel;

[0008] Calculate the skylight spectrum received by each pixel in the water hyperspectral image based on the spectra received at the first preset position and the second preset position in the water hyperspectral image, and the relative radiation amounts of the skylight received at the first preset position and the second preset position; wherein, the difference between the water-leaving radiation spectra at the first preset position and the second preset position is within a preset difference range.

[0009] Calculate the water-leaving radiation spectrum of each pixel in the water hyperspectral image based on the spectrum received by each pixel in the water hyperspectral image and the skylight spectrum.

[0010] In a possible implementation manner, the calculating the angle of the skylight received by each pixel in the water hyperspectral image captured obliquely by the hyperspectral camera according to the tilt angle and the field of view angle of the hyperspectral camera, and recording it as the skylight reflection angle corresponding to this pixel includes:

[0011] According to Calculate the angle of the skylight received by each pixel in the water hyperspectral image captured obliquely by the hyperspectral camera, and record it as the skylight reflection angle corresponding to this pixel.

[0012] wherein, θ m is the skylight reflection angle corresponding to each pixel in the m-th row in the field of view direction of the water hyperspectral image, θ is the tilt angle of the hyperspectral camera, is the field of view angle of the hyperspectral camera, and M is the total number of rows in the field of view direction of the water hyperspectral image.

[0013] In a possible implementation manner, the calculating the relative radiation amount of the skylight received by each pixel in the water hyperspectral image based on the law of specular reflection of the water surface and the distribution law of the skylight, according to the skylight reflection angle corresponding to each pixel includes:

[0014] Based on the law of specular reflection of the water surface, determine the incident angle and the refraction angle of the skylight corresponding to each pixel according to the skylight reflection angle corresponding to each pixel.

[0015] According to the incident angle and the refraction angle of the skylight corresponding to each pixel, determine the first component perpendicular to the plane of incidence and the second component parallel to the plane of incidence of the skylight received by each pixel.

[0016] According to the first component and the second component, calculate the total reflectance of the light intensity of the skylight received by each pixel.

[0017] Based on the distribution law of the light intensity of skylight at different solar zenith angles and zenith angles, according to the light intensity of skylight at the zenith angle corresponding to the same skylight reflection angle of each pixel point and the total reflectivity of the light intensity of skylight received by the corresponding pixel point, calculate the relative radiation amount of skylight received by each pixel point.

[0018] In a possible implementation, based on the law of water surface reflection, according to the skylight reflection angle corresponding to each pixel point, determining the skylight incident angle and skylight refraction angle corresponding to each pixel point includes:

[0019] Based on the law of water surface reflection, according to the skylight reflection angle corresponding to each pixel point, determining the skylight incident angle corresponding to each pixel point;

[0020] Based on the law of water surface refraction, according to the skylight incident angle corresponding to each pixel point, determining the skylight refraction angle corresponding to each pixel point.

[0021] In a possible implementation, according to the skylight incident angle and skylight refraction angle corresponding to each pixel point, determining the first component of the skylight received by each pixel point vibrating perpendicular to the incident plane and the second component vibrating parallel to the incident plane includes:

[0022] According to Determine the first component of the skylight received by each pixel point vibrating perpendicular to the incident plane and the second component vibrating parallel to the incident plane;

[0023] Wherein, R s is the first component of the skylight received by each pixel point vibrating perpendicular to the incident plane, R p is the second component of the skylight received by each pixel point vibrating parallel to the incident plane, θ t is the skylight refraction angle corresponding to each pixel point, θ i is the skylight incident angle corresponding to each pixel point.

[0024] In a possible implementation, according to the first component and the second component, calculating the total reflectivity of the light intensity of the skylight received by each pixel point includes:

[0025] According to Calculate the total reflectivity of the light intensity of the skylight received by each pixel point;

[0026] Wherein, R is the total reflectivity of the light intensity of the skylight received by each pixel point, R s is the first component of the skylight received by each pixel point vibrating perpendicular to the incident plane, R p is the second component of the skylight received by each pixel point vibrating parallel to the incident plane.

[0027] In a possible implementation manner, calculating the skylight spectrum received by each pixel in the water body hyperspectral image based on the spectra received at the first preset position and the second preset position in the water body hyperspectral image, and the relative radiation amounts of the skylight received at the first preset position and the second preset position, includes:

[0028] Calculating the skylight spectrum received at the first preset position based on the spectra received at the first preset position and the second preset position in the water body hyperspectral image, and the relative radiation amounts of the skylight received at the first preset position and the second preset position;

[0029] Calculating the skylight spectrum received by each pixel in the water body hyperspectral image based on the skylight spectrum received at the first preset position and the relative radiation amount of the skylight, and the relative radiation amounts of the skylight received by each pixel in the water body hyperspectral image.

[0030] In a second aspect, an off-water radiation spectrum calculation device provided by an embodiment of the present invention includes:

[0031] A first calculation module, configured to calculate the angle of the skylight received by each pixel in the water body hyperspectral image captured obliquely by the hyperspectral camera according to the tilt angle and the field of view angle of the hyperspectral camera, and record it as the skylight reflection angle corresponding to the pixel;

[0032] A second calculation module, configured to calculate the relative radiation amount of the skylight received by each pixel in the water body hyperspectral image according to the skylight reflection angle corresponding to each pixel based on the water surface reflection law and the distribution law of the skylight;

[0033] A third calculation module, configured to calculate the skylight spectrum received by each pixel in the water body hyperspectral image based on the spectra received at the first preset position and the second preset position in the water body hyperspectral image, and the relative radiation amounts of the skylight received at the first preset position and the second preset position; wherein, the difference between the off-water radiation spectra of the first preset position and the second preset position is within a preset difference range;

[0034] A fourth calculation module, configured to calculate the off-water radiation spectrum of each pixel in the water body hyperspectral image based on the spectrum and the skylight spectrum received by each pixel in the water body hyperspectral image.

[0035] In a third aspect, an embodiment of the present invention provides a terminal, including a memory and a processor, where the memory is used to store a computer program, and the processor is used to call and run the computer program stored in the memory to execute the steps of the method described in the first aspect or any possible implementation manner of the first aspect above.

[0036] Fourthly, an embodiment of the present invention provides a computer-readable storage medium storing a computer program, and when the computer program is executed by a processor, the steps of the method described in the first aspect or any possible implementation manner of the first aspect above are implemented.

[0037] An embodiment of the present invention provides a method, device, terminal and storage medium for calculating the radiance spectrum of water leaving the surface. First, according to the tilt angle and field of view angle of a hyperspectral camera, the sky light reflection angle corresponding to each pixel in the water hyperspectral image taken by the tilted hyperspectral camera is calculated; then, based on the water surface reflection law and the distribution law of skylight, according to the sky light reflection angle corresponding to each pixel, the relative radiance of skylight received by each pixel in the water hyperspectral image is calculated; furthermore, based on the spectra received at the first preset position and the second preset position where the difference in the radiance spectrum of water leaving the surface in the water hyperspectral image is within a preset difference range, and the relative radiance of skylight received at the first preset position and the second preset position, the skylight spectrum received by each pixel in the water hyperspectral image is calculated; thus, the corresponding skylight spectrum can be effectively deducted from the spectra received by each pixel in the water hyperspectral image, and the accurate radiance spectrum of water leaving the surface for each pixel in the water hyperspectral image can be calculated, thereby avoiding the problem that the noise ratio of the radiance spectrum of water leaving the surface in the water hyperspectral image obtained by tilting the hyperspectral camera to shoot the water surface is relatively large and is not conducive to subsequent data processing, and improving the total signal-to-noise ratio of the radiance spectrum of water leaving the surface in the water hyperspectral image and the subsequent inversion of water color remote sensing parameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the following drawings are only some embodiments of the present invention, and those of ordinary skill in the art can also obtain other drawings without creative efforts based on these drawings.

[0039] Figure 1 is a schematic diagram of a water hyperspectral image obtained by tilting a hyperspectral camera to shoot the water surface provided by an embodiment of the present invention;

[0040] Figure 2 is a flowchart of the implementation of the method for calculating the radiance spectrum of water leaving the surface provided by an embodiment of the present invention;

[0041] Figure 3 is a schematic diagram of the tilt angle and field of view angle of a hyperspectral camera provided by an embodiment of the present invention;

[0042] Figure 4 is a schematic diagram of the distribution of the light intensity of skylight with different solar zenith angles and zenith angles provided by an embodiment of the present invention;

[0043] Figure 5 It is a schematic structural diagram of a device for calculating the off - water radiation spectrum provided by an embodiment of the present invention;

[0044] Figure 6 It is a schematic diagram of a terminal provided by an embodiment of the present invention. Detailed implementation manners

[0045] In the following description, for the purpose of illustration rather than limitation, specific details such as specific system structures and technologies are presented to thoroughly understand the embodiments of the present invention. However, those skilled in the art should clearly understand that the present invention can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well - known systems, devices, circuits, and methods are omitted to avoid unnecessary details from interfering with the description of the present invention.

[0046] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will be described through specific embodiments in conjunction with the accompanying drawings.

[0047] Refer to Figure 2 , which shows the implementation flowchart of the off - water radiation spectrum calculation method provided by an embodiment of the present invention, and is described in detail as follows:

[0048] In step 201, according to the tilt angle and field - of - view angle of the hyperspectral camera, calculate the angle of skylight received by each pixel in the hyperspectral image of the water body taken by the tilted hyperspectral camera, and denote it as the skylight reflection angle corresponding to this pixel.

[0049] Optionally, according to the [description missing in the original, assumed to be relevant parameters of the hyperspectral camera], calculating the angle of skylight received by each pixel in the hyperspectral image of the water body taken by the tilted hyperspectral camera, and denoting it as the skylight reflection angle corresponding to this pixel, may include:

[0050] According to Calculate the angle of skylight received by each pixel in the hyperspectral image of the water body taken by the tilted hyperspectral camera, and denote it as the skylight reflection angle corresponding to this pixel.

[0051] Among them, θ m is the skylight reflection angle corresponding to each pixel in the m - th row in the field - of - view direction of the water - body hyperspectral image, θ is the tilt angle of the hyperspectral camera, is the field - of - view angle of the hyperspectral camera, and M is the total number of rows in the field - of - view direction of the water - body hyperspectral image.

[0052] In this embodiment, as Figure 3 shown, since the tilt angle and field - of - view angle of the hyperspectral camera are known, and because the reflection angle is equal to the incident angle during specular reflection, the angle of skylight received by each pixel in the hyperspectral image of the water body taken within the field - of - view angle of the hyperspectral camera can be calculated.

[0053] In step 202, based on the water surface reflection law and the distribution law of skylight, according to the skylight reflection angle corresponding to each pixel, calculate the relative radiation amount of skylight received by each pixel in the water body hyperspectral image.

[0054] Optionally, based on the water surface reflection law and the distribution law of skylight, according to the skylight reflection angle corresponding to each pixel, calculating the relative radiation amount of skylight received by each pixel in the water body hyperspectral image may include:

[0055] Based on the water surface reflection law, according to the skylight reflection angle corresponding to each pixel, determine the skylight incident angle and skylight refraction angle corresponding to each pixel.

[0056] According to the skylight incident angle and skylight refraction angle corresponding to each pixel, determine the first component of the skylight perpendicular to the vibration of the incident plane and the second component parallel to the vibration of the incident plane received by each pixel.

[0057] According to the first component and the second component, calculate the total reflectance of the skylight intensity received by each pixel.

[0058] Based on the distribution law of the skylight intensity at different solar zenith angles and zenith angles, according to the skylight intensity at the zenith angle corresponding to the skylight reflection angle corresponding to each pixel and the total reflectance of the skylight intensity received by the corresponding pixel, calculate the relative radiation amount of skylight received by each pixel.

[0059] Optionally, based on the water surface reflection law, according to the skylight reflection angle corresponding to each pixel, determining the skylight incident angle and skylight refraction angle corresponding to each pixel includes: based on the water surface reflection law, according to the skylight reflection angle corresponding to each pixel, determining the skylight incident angle corresponding to each pixel; based on the water surface refraction law, according to the skylight incident angle corresponding to each pixel, determining the skylight refraction angle corresponding to each pixel.

[0060] In this embodiment, based on the water surface reflection law, the skylight reflection angle corresponding to each pixel is equal to the skylight incident angle corresponding to each pixel, so the skylight incident angle corresponding to each pixel can be determined. Since the reflection of the water surface conforms to the refraction law, then:

[0061]

[0062] where θ i is the skylight incident angle corresponding to each pixel, θ t is the skylight refraction angle corresponding to each pixel, n2 is the refractive index of water, and n1 is the refractive index of air. In this embodiment, n2 = 1.333 and n1 = 1. Therefore, when n1, n2, and the skylight incident angle θ corresponding to each pixel are known iWhen, based on the law of refraction of light on the water surface, the refraction angle θ of the skylight corresponding to each pixel can be determined t .

[0063] Optionally, determining the first component perpendicular to the plane of incidence and the second component parallel to the plane of incidence of the skylight received by each pixel according to the incident angle and refraction angle of the skylight corresponding to each pixel may include:

[0064] According to Determine the first component perpendicular to the plane of incidence and the second component parallel to the plane of incidence of the skylight received by each pixel.

[0065] Wherein, R s is the first component perpendicular to the plane of incidence of the skylight received by each pixel, and R p is the second component parallel to the plane of incidence of the skylight received by each pixel, θ t is the refraction angle of the skylight corresponding to each pixel, and θ i is the incident angle of the skylight corresponding to each pixel.

[0066] In this embodiment, since the reflected light can be divided into a component R s perpendicular to the plane of incidence and a component R p parallel to the plane of incidence according to its polarization angle. And the reflectivities of the component R s perpendicular to the plane of incidence and the component R p parallel to the plane of incidence are different, and their energy distributions respectively follow the following laws:

[0067]

[0068] Therefore, according to the incident angle and refraction angle of the skylight corresponding to each pixel, the magnitudes of the first component R s perpendicular to the plane of incidence and the second component R p parallel to the plane of incidence of the skylight received by each pixel can be determined.

[0069] Optionally, calculating the total reflectivity of the light intensity of the skylight received by each pixel according to the first component and the second component may include:

[0070] According to Calculate the total reflectivity of the light intensity of the skylight received by each pixel.

[0071] Wherein, R is the total reflectivity of the light intensity of the skylight received by each pixel, and R s is the first component perpendicular to the plane of incidence of the skylight received by each pixel, and R p is the second component parallel to the plane of incidence of the skylight received by each pixel.

[0072] In this embodiment, after determining the magnitude of the first component R of the skylight received by each pixel point vibrating perpendicular to the incident plane s and the second component R vibrating parallel to the incident plane p for the intensity of the received skylight, its total reflectance is:

[0073] On this basis, the intensity of the skylight at different solar zenith angles and zenith angles follows the distribution as Figure 4 shown. Based on Figure 4 , after determining the solar zenith angle, the intensity of the skylight at the zenith angle with the same skylight reflection angle corresponding to each pixel point can be determined from Figure 4 . Then, by multiplying the intensity of the skylight at the zenith angle with the same skylight reflection angle corresponding to each pixel point by the total reflectance of the intensity of the skylight received by this pixel point, the relative radiation amount of the skylight received by this pixel point can be calculated.

[0074] It should be noted that the distribution law of the intensity of the skylight at different solar zenith angles and zenith angles can also be reflected in the form of a table or formula. This embodiment only takes Figure 4 as an example and does not limit the manifestation form of the distribution law of the intensity of the skylight at different solar zenith angles and zenith angles.

[0075] In step 203, based on the spectra received at the first preset position and the second preset position in the water body hyperspectral image, and the relative radiation amounts of the skylight received at the first preset position and the second preset position, calculate the skylight spectrum received by each pixel point in the water body hyperspectral image.

[0076] Among them, the difference between the water-leaving radiation spectra at the first preset position and the second preset position is within the preset difference range.

[0077] In this embodiment, before or after tilting the hyperspectral camera to capture the water body hyperspectral image, according to the on-site situation, two pixel points or two regions with similar water-leaving radiation spectra in the water body hyperspectral image can be first determined as the first preset position and the second preset position. Or two pixel points or two regions with the most similar water-leaving radiation spectra can also be first determined from multiple pixel points or multiple regions with similar water-leaving radiation spectra in the water body hyperspectral image as the first preset position and the second preset position. Thus, based on the spectra received at the first preset position and the second preset position, and the relative radiation amounts of the skylight received at the first preset position and the second preset position, calculate the skylight spectrum received by each pixel point in the water body hyperspectral image.

[0078] Optionally, calculating the skylight spectrum received by each pixel in the water hyperspectral image based on the spectra received at the first preset position and the second preset position in the water hyperspectral image, and the relative radiation amounts of skylight received at the first preset position and the second preset position may include:

[0079] Calculating the skylight spectrum received at the first preset position based on the spectra received at the first preset position and the second preset position in the water hyperspectral image, and the relative radiation amounts of skylight received at the first preset position and the second preset position.

[0080] Calculating the skylight spectrum received by each pixel in the water hyperspectral image based on the skylight spectrum received at the first preset position and the relative radiation amount of skylight, and the relative radiation amounts of skylight received by each pixel in the water hyperspectral image.

[0081] In this embodiment, after determining the first preset position and the second preset position, based on the water hyperspectral image, the spectrum F(A) received at the first preset position and the spectrum F(B) received at the second preset position in the water hyperspectral image can be obtained. Let L(A) represent the relative radiation amount of skylight received at the first preset position, L(B) represent the relative radiation amount of skylight received at the second preset position, and assume that the skylight spectrum received at the first preset position is F(skyA), the water-leaving radiation spectrum at the first preset position is F(waterA), the skylight spectrum received at the second preset position is F(skyB), and the water-leaving radiation spectrum at the second preset position is F(waterB). Then:

[0082]

[0083] Also, since: And F(waterA)≈F(waterB), it can be considered that F(waterA)=F(waterB). Then, based on the spectrum F(A) received at the first preset position, the spectrum F(B) received at the second preset position, the relative radiation amount L(A) of skylight received at the first preset position, and the relative radiation amount L(B) of skylight received at the second preset position, the skylight spectrum F(skyA) received at the first preset position can be calculated:

[0084]

[0085] On this basis, assume that the skylight spectrum received by any pixel in the water hyperspectral image is F(skyX), and the relative radiation amount of skylight received by any pixel is L(X). Since Then, the skylight spectrum received by each pixel in the water hyperspectral image can be calculated:

[0086] It should be noted that if the first preset position and the second preset position are two regions with similar water-leaving radiation spectra, the relative radiation amount of skylight received at the first preset position can be obtained by calculating the average value of the relative radiation amounts of skylight received by all pixel points in the region corresponding to the first preset position, and the relative radiation amount of skylight received at the second preset position can be obtained by calculating the average value of the relative radiation amounts of skylight received by all pixel points in the region corresponding to the second preset position.

[0087] In step 204, based on the spectra received by each pixel point in the water body hyperspectral image and the skylight spectrum, the water-leaving radiation spectrum of each pixel point in the water body hyperspectral image is calculated.

[0088] Since the skylight spectrum F(skyX) received by each pixel point in the water body hyperspectral image is calculated in the above steps, and the spectrum F(X) received by each pixel point in the water body hyperspectral image is F(X)=F(waterX)+F(skyX), the water-leaving radiation spectrum F(waterX) of each pixel point in the water body hyperspectral image can be calculated by F(waterX)=F(X)-F(skyX).

[0089] This embodiment can subtract skylight when remotely retrieving hyperspectral water quality parameters of natural water bodies such as lakes, rivers, and seawater in the advanced environmental protection industry, ecological industry, optical detection industry, marine engineering equipment industry, drawing, computing and measuring instrument manufacturing, geospatial remote sensing information service, software development, information processing, and storage support services, so as to obtain an accurate water-leaving radiation spectrum.

[0090] In the embodiment of the present invention, first, according to the tilt angle and field of view angle of the hyperspectral camera, the skylight reflection angle corresponding to each pixel point in the water body hyperspectral image taken by the tilted hyperspectral camera is calculated; then, based on the water surface reflection law and the distribution law of skylight, according to the skylight reflection angle corresponding to each pixel point, the relative radiation amount of skylight received by each pixel point in the water body hyperspectral image is calculated; furthermore, based on the spectra received at the first preset position and the second preset position where the difference in the water-leaving radiation spectra in the water body hyperspectral image is within the preset difference range, and the relative radiation amounts of skylight received at the first preset position and the second preset position, the skylight spectrum received by each pixel point in the water body hyperspectral image is calculated; thus, the corresponding skylight spectrum can be effectively subtracted from the spectra received by each pixel point in the water body hyperspectral image, and the accurate water-leaving radiation spectrum of each pixel point in the water body hyperspectral image can be calculated, thereby avoiding the problem that the noise ratio of the water-leaving radiation spectrum of the water body hyperspectral image obtained by the tilted hyperspectral camera shooting the water surface is relatively large and is not conducive to subsequent data processing, and improving the overall signal-to-noise ratio of the water-leaving radiation spectrum of the water body hyperspectral image and the subsequent retrieval of water color remote sensing parameters.

[0091] It should be understood that the sequence numbers of the steps in the above embodiments do not imply the order of execution. The execution order of each process should be determined according to its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.

[0092] The following is the device embodiment of the present invention. For the details not described in detail, reference may be made to the corresponding method embodiments above.

[0093] Figure 5 The structural schematic diagram of the water-leaving radiance spectrum calculation device provided by the embodiment of the present invention is shown. For the convenience of description, only the parts related to the embodiment of the present invention are shown and are described in detail as follows:

[0094] As Figure 5 shown, the water-leaving radiance spectrum calculation device includes: a first calculation module 51, a second calculation module 52, a third calculation module 53, and a fourth calculation module 54.

[0095] The first calculation module 51 is configured to calculate the angle of skylight received by each pixel in the water hyperspectral image captured obliquely by the hyperspectral camera according to the tilt angle and field of view angle of the hyperspectral camera, which is denoted as the skylight reflection angle corresponding to the pixel.

[0096] The second calculation module 52 is configured to calculate the relative radiance of skylight received by each pixel in the water hyperspectral image according to the skylight reflection angle corresponding to each pixel based on the water surface reflection law and the distribution law of skylight.

[0097] The third calculation module 53 is configured to calculate the skylight spectrum received by each pixel in the water hyperspectral image based on the spectra received at a first preset position and a second preset position in the water hyperspectral image, and the relative radiance of skylight received at the first preset position and the second preset position; wherein, the difference between the water-leaving radiance spectra of the first preset position and the second preset position is within a preset difference range.

[0098] The fourth calculation module 54 is configured to calculate the water-leaving radiance spectrum of each pixel in the water hyperspectral image based on the spectrum and skylight spectrum received by each pixel in the water hyperspectral image.

[0099] In the embodiment of the present invention, first, according to the inclination angle and the field of view angle of the hyperspectral camera, the skylight reflection angle corresponding to each pixel in the hyperspectral image of the water body taken by the tilted hyperspectral camera is calculated; then, based on the water surface reflection law and the distribution law of skylight, according to the skylight reflection angle corresponding to each pixel, the relative radiation amount of skylight received by each pixel in the hyperspectral image of the water body is calculated; furthermore, based on the spectra received at the first preset position and the second preset position where the difference in the radiance spectra of the water-leaving radiation in the hyperspectral image of the water body is within a preset difference range, and the relative radiation amounts of skylight received at the first preset position and the second preset position, the skylight spectrum received by each pixel in the hyperspectral image of the water body is calculated; thus, the corresponding skylight spectrum can be effectively deducted from the spectra received by each pixel in the hyperspectral image of the water body, and the accurate water-leaving radiation spectrum of each pixel in the hyperspectral image of the water body can be calculated, thereby avoiding the problem that the noise ratio of the water-leaving radiation spectrum of the hyperspectral image of the water body obtained by tilting the hyperspectral camera to photograph the water surface is relatively large and is not conducive to subsequent data processing, and improving the total signal-to-noise ratio of the water-leaving radiation spectrum of the hyperspectral image of the water body and the subsequent inversion of water color remote sensing parameters.

[0100] In one possible implementation, the first calculation module 51 may be configured to, according to calculate the angle of skylight received by each pixel in the hyperspectral image of the water body taken by the tilted hyperspectral camera, denoted as the skylight reflection angle corresponding to this pixel;

[0101] where θ m is the skylight reflection angle corresponding to each pixel in the m-th row in the field of view direction of the hyperspectral image of the water body, θ is the inclination angle of the hyperspectral camera, is the field of view angle of the hyperspectral camera, and M is the total number of rows in the field of view direction of the hyperspectral image of the water body.

[0102] In one possible implementation, the second calculation module 52 may be configured to, based on the water surface reflection law, determine the incident angle and the refraction angle of skylight corresponding to each pixel according to the skylight reflection angle corresponding to each pixel;

[0103] According to the incident angle and the refraction angle of skylight corresponding to each pixel, determine the first component perpendicular to the plane of incidence and the second component parallel to the plane of incidence of the skylight received by each pixel;

[0104] According to the first component and the second component, calculate the total reflectance of the light intensity of the skylight received by each pixel;

[0105] Based on the distribution law of the light intensity of skylight at different solar zenith angles and zenith angles, according to the light intensity of skylight at the zenith angle corresponding to the same skylight reflection angle of each pixel point and the total reflectance of the light intensity of skylight received by the corresponding pixel point, calculate the relative radiation amount of skylight received by each pixel point.

[0106] In a possible implementation, the second calculation module 52 can be used to determine the incident angle of skylight corresponding to each pixel point according to the skylight reflection angle corresponding to each pixel point based on the water surface reflection law;

[0107] Based on the water surface refraction law, determine the refraction angle of skylight corresponding to each pixel point according to the incident angle of skylight corresponding to each pixel point.

[0108] In a possible implementation, the second calculation module 52 can be used to determine the first component of the skylight received by each pixel point vibrating perpendicular to the incident plane and the second component vibrating parallel to the incident plane;

[0109] where R s is the first component of the skylight received by each pixel point vibrating perpendicular to the incident plane, and R p is the second component of the skylight received by each pixel point vibrating parallel to the incident plane, θ t is the refraction angle of skylight corresponding to each pixel point, and θ i is the incident angle of skylight corresponding to each pixel point.

[0110] In a possible implementation, the second calculation module 52 can be used to calculate the total reflectance of the light intensity of skylight received by each pixel point;

[0111] where R is the total reflectance of the light intensity of skylight received by each pixel point, and R s is the first component of the skylight received by each pixel point vibrating perpendicular to the incident plane, and R p is the second component of the skylight received by each pixel point vibrating parallel to the incident plane.

[0112] In a possible implementation, the third calculation module 53 can be used to calculate the skylight spectrum received at the first preset position based on the spectra received at the first preset position and the second preset position in the water body hyperspectral image, and the relative radiation amount of skylight received at the first preset position and the second preset position;

[0113] Based on the skylight spectrum received at the first preset position and the relative radiation amount of skylight, and the relative radiation amount of skylight received by each pixel point in the water body hyperspectral image, calculate the skylight spectrum received by each pixel point in the water body hyperspectral image.

[0114] Figure 6 It is a schematic diagram of the terminal provided by an embodiment of the present invention. As Figure 6 shown, the terminal 6 of this embodiment includes: a processor 60, a memory 61, and a computer program 62 stored in the memory 61 and executable on the processor 60. When the processor 60 executes the computer program 62, the steps in the above-mentioned embodiments of various off-water radiation spectrum calculation methods are implemented, such as Figure 2 the steps 201 to 204 shown. Alternatively, when the processor 60 executes the computer program 62, the functions of each module / unit in the above-mentioned device embodiments are implemented, such as Figure 5 the functions of the modules / units 51 to 54 shown.

[0115] Exemplarily, the computer program 62 can be divided into one or more modules / units. One or more modules / units are stored in the memory 61 and executed by the processor 60 to complete the present invention. One or more modules / units can be a series of computer program instruction segments capable of performing specific functions, and these instruction segments are used to describe the execution process of the computer program 62 in the terminal 6. For example, the computer program 62 can be divided into Figure 5 the modules / units 51 to 54 shown.

[0116] The terminal 6 can be a computing device such as a desktop computer, a notebook, a palm computer, and a cloud server. The terminal 6 may include, but is not limited to, a processor 60 and a memory 61. Those skilled in the art can understand that Figure 6 this is only an example of the terminal 6 and does not constitute a limitation on the terminal 6. It may include more or fewer components than those shown in the figure, or combine certain components, or different components. For example, the terminal may further include input / output devices, network access devices, a bus, etc.

[0117] The so-called processor 60 may be a central processing unit (CPU), or may also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or this processor may also be any conventional processor, etc.

[0118] The memory 61 can be an internal storage unit of the terminal 6, such as the hard disk or memory of the terminal 6. The memory 61 can also be an external storage device of the terminal 6, such as a plug-in hard disk equipped on the terminal 6, a Smart Media Card (SMC), a Secure Digital (SD) card, a Flash Card, etc. Further, the memory 61 can also include both the internal storage unit of the terminal 6 and the external storage device. The memory 61 is used to store computer programs and other programs and data required by the terminal. The memory 61 can also be used to temporarily store the data that has been output or will be output.

[0119] Those skilled in the art can clearly understand that, for the convenience and conciseness of description, only the above division of each functional unit and module is used as an example. In actual applications, the above functions can be allocated to different functional units and modules according to needs, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiment can be integrated into a processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above integrated unit can be implemented in the form of hardware or in the form of a software functional unit. In addition, the specific names of each functional unit and module are only for the convenience of mutual distinction and do not limit the protection scope of the present application. The specific working processes of the units and modules in the above system can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated here.

[0120] In the above embodiments, the descriptions of the various embodiments have their own emphases. For the parts not detailed or recorded in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0121] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or by a combination of computer software and electronic hardware. Whether these functions are executed in hardware or software depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0122] In the embodiments provided by the present invention, it should be understood that the disclosed device / terminal and method can be implemented in other ways. For example, the device / terminal embodiments described above are merely illustrative. For example, the division of modules or units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces. The indirect couplings or communication connections of devices or units can be in electrical, mechanical or other forms.

[0123] The units described as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0124] In addition, in each embodiment of the present invention, the functional units can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional units.

[0125] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, to implement all or part of the processes in the above-mentioned embodiment methods of the present invention, it can also be completed by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, the steps of the above-mentioned various embodiments of the off-water radiation spectrum calculation method can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in the form of source code, object code, executable file or some intermediate form, etc. The computer-readable medium can include: any entity or device that can carry the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal, and software distribution medium, etc.

[0126] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method for calculating the off-water radiation spectrum, characterized in that, Including: According to the tilt angle and field of view angle of the hyperspectral camera, calculate the angle of skylight received by each pixel in the hyperspectral image of the water body captured by the tilted hyperspectral camera, denoted as the skylight reflection angle corresponding to this pixel; Based on the water surface reflection law and the distribution law of skylight, calculate the relative radiation amount of skylight received by each pixel in the hyperspectral image of the water body according to the skylight reflection angle corresponding to each pixel; Based on the spectra received at the first preset position and the second preset position in the hyperspectral image of the water body, and the relative radiation amounts of skylight received at the first preset position and the second preset position, calculate the skylight spectrum received by each pixel in the hyperspectral image of the water body; wherein, the difference between the water-leaving radiation spectra at the first preset position and the second preset position is within a preset difference range; Based on the spectra and skylight spectra received by each pixel in the hyperspectral image of the water body, calculate the water-leaving radiation spectrum of each pixel in the hyperspectral image of the water body.

2. The method for calculating the radiation spectrum out of water according to claim 1, wherein The step of calculating the angle of skylight received by each pixel in the hyperspectral image of the water body captured by the tilted hyperspectral camera according to the tilt angle and field of view angle of the hyperspectral camera, and denoting it as the skylight reflection angle corresponding to this pixel, includes: According to Calculate the angle of the skylight received by each pixel in the hyperspectral image of the water body taken by the tilted hyperspectral camera, and record it as the skylight reflection angle corresponding to this pixel; where θ m is the skylight reflection angle corresponding to each pixel in the m-th row in the field of view direction of the hyperspectral image of the water body, θ is the inclination angle of the hyperspectral camera, is the field of view angle of the hyperspectral camera, and M is the total number of rows in the field of view direction of the hyperspectral image of the water body.

3. The method for calculating the radiation spectrum out of water according to claim 1, wherein The step of calculating the relative radiation amount of skylight received by each pixel in the hyperspectral image of the water body based on the water surface reflection law and the distribution law of skylight according to the skylight reflection angle corresponding to each pixel, includes: Based on the water surface reflection law, determine the incident angle and refraction angle of skylight corresponding to each pixel according to the skylight reflection angle corresponding to each pixel; According to the incident angle and refraction angle of skylight corresponding to each pixel, determine the first component perpendicular to the plane of incidence and the second component parallel to the plane of incidence of the skylight received by each pixel; According to the first component and the second component, calculate the total reflectance of the light intensity of the skylight received by each pixel; Based on the distribution law of the light intensity of skylight at different solar zenith angles and zenith angles, calculate the relative radiation amount of skylight received by each pixel according to the light intensity of skylight at the zenith angle same as the skylight reflection angle corresponding to each pixel and the total reflectance of the light intensity of the skylight received by the corresponding pixel.

4. The method for calculating the off-water radiation spectrum according to claim 3, wherein The step of determining the incident angle and refraction angle of skylight corresponding to each pixel based on the water surface reflection law according to the skylight reflection angle corresponding to each pixel, includes: Based on the water surface reflection law, determine the incident angle of skylight corresponding to each pixel according to the skylight reflection angle corresponding to each pixel; Based on the water surface refraction law, determine the refraction angle of skylight corresponding to each pixel according to the incident angle of skylight corresponding to each pixel.

5. The method for calculating the radiation spectrum out of water according to claim 3, wherein The step of determining the first component perpendicular to the plane of incidence and the second component parallel to the plane of incidence of the skylight received by each pixel according to the incident angle and refraction angle of skylight corresponding to each pixel, includes: According to determine a first component perpendicular to the incident plane of vibration and a second component parallel to the incident plane of vibration of the skylight received by each pixel point; wherein, R s is the first component of the skylight received by each pixel vibrating perpendicular to the incident plane, R p is the second component of the skylight received by each pixel vibrating parallel to the incident plane, θ t is the refraction angle of the skylight corresponding to each pixel, θ i is the incident angle of the skylight corresponding to each pixel.

6. The method for calculating the radiation spectrum out of water according to claim 3, wherein The step of calculating the total reflectance of the light intensity of the skylight received by each pixel according to the first component and the second component, includes: According to calculate the total reflectance of the light intensity of skylight received by each pixel point; where R is the total reflectance of the light intensity of skylight received by each pixel, R s is the first component of the skylight received by each pixel vibrating perpendicular to the incident plane, R p is the second component of the skylight received by each pixel vibrating parallel to the incident plane.

7. The method for calculating the radiation spectrum out of water according to any one of claims 1-6, characterized in that Calculating the skylight spectrum received by each pixel in the water hyperspectral image based on the spectra received at the first preset position and the second preset position in the water hyperspectral image, and the relative radiation amounts of the skylight received at the first preset position and the second preset position, includes: Calculating the skylight spectrum received at the first preset position based on the spectra received at the first preset position and the second preset position in the water hyperspectral image, and the relative radiation amounts of the skylight received at the first preset position and the second preset position; Calculating the skylight spectrum received by each pixel in the water hyperspectral image based on the skylight spectrum received at the first preset position and the relative radiation amount of the skylight, and the relative radiation amounts of the skylight received by each pixel in the water hyperspectral image.

8. A device for calculating the off-water radiation spectrum, characterized in that, Includes: A first calculation module, configured to calculate the angle of the skylight received by each pixel in the water hyperspectral image captured by the tilted hyperspectral camera according to the tilt angle and the field of view angle of the hyperspectral camera, denoted as the skylight reflection angle corresponding to this pixel; A second calculation module, configured to calculate the relative radiation amount of the skylight received by each pixel in the water hyperspectral image based on the law of specular reflection of the water surface and the distribution law of the skylight according to the skylight reflection angle corresponding to each pixel; A third calculation module, configured to calculate the skylight spectrum received by each pixel in the water hyperspectral image based on the spectra received at the first preset position and the second preset position in the water hyperspectral image, and the relative radiation amounts of the skylight received at the first preset position and the second preset position; wherein, the difference between the spectra of the water-leaving radiation at the first preset position and the second preset position is within a preset difference range; A fourth calculation module, configured to calculate the water-leaving radiation spectrum of each pixel in the water hyperspectral image based on the spectrum and the skylight spectrum received by each pixel in the water hyperspectral image.

9. A terminal, characterized in that, Includes a memory and a processor, the memory is used to store a computer program, and the processor is used to call and run the computer program stored in the memory to execute the method according to any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, the steps of the method according to any one of claims 1 to 7 above are implemented.

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