Spectral radiation joint calibration method and device for spaceborne hyperspectral remote sensor

Abstract

The present invention relates to the field of remote sensing technology, and in particular to a spectral radiation joint calibration method and device for a satellite-borne hyperspectral remote sensor. The present invention realizes the joint calibration of the spectrum and radiation calibration parameters of the satellite-borne hyperspectral remote sensor by constructing a spectral radiation joint calibration model of the satellite-borne hyperspectral remote sensor based on an atmospheric radiation transmission simulation model and remote sensor observation values. Compared with the current hyperspectral payload spectrum and radiation independent or cyclic iteration calibration method, the present invention can simultaneously obtain the spectrum and radiation calibration parameters of the satellite-borne hyperspectral remote sensor, and has obvious advantages in solving the coupling and entanglement problem of the two in the spectrum and radiation calibration process of the satellite-borne hyperspectral remote sensor and improving the calibration accuracy.

Description

Technical Field

[0001] The present invention relates to the field of remote sensing technology, and in particular to a spectral radiation joint calibration method and device for a satellite-borne hyperspectral remote sensor. Background Art

[0002] With the development of hyperspectral remote sensing technology, it has become a hot topic and technological frontier that has attracted attention at home and abroad due to its important application potential and value in industries such as agricultural and forestry classification, land and resources survey, ecological environment protection, and ground object identification, as well as its huge advantages in obtaining surface information at regional and even global scales.

[0003] In the prior art, the spectrum and radiation calibration of satellite-borne hyperspectral remote sensors are mainly carried out by independent calibration, that is, under the assumption that the laboratory spectrum calibration parameters (central wavelength and half-wave width FWHM) remain unchanged, the radiation calibration parameters (gain and bias) of satellite-borne hyperspectral remote sensing are obtained by field calibration; then, the radiation calibration parameters obtained by field calibration are used as input to perform field spectrum calibration on the satellite-borne hyperspectral remote sensor to obtain the on-orbit spectrum calibration parameters of satellite-borne hyperspectral remote sensing. In other technical solutions of the prior art, the final spectrum and radiation calibration parameters are calculated by iterating the two processes of field radiation calibration and spectrum calibration, which increases the error accumulation caused by the iterative process.

[0004] There are at least the following disadvantages in the prior art: when performing absolute radiation calibration of a hyperspectral remote sensor, it is necessary to assume that the spectral performance parameters of the target hyperspectral remote sensor are known and accurate; and when performing spectral calibration of hyperspectral remote sensing, it is also necessary to assume that the absolute radiation calibration coefficient of the hyperspectral remote sensor is known, and perform spectral and radiation calibration separately, which is bound to bring certain uncertainties to the spectral and radiation calibration results, thereby reducing the calibration accuracy of the two. Summary of the invention

[0005] The present invention provides a spectral radiation joint calibration method and device for a satellite-borne hyperspectral remote sensor, which are used to solve the calibration error problem caused by mutual coupling and entanglement during the on-orbit spectrum and radiation calibration of the satellite-borne hyperspectral remote sensor in the prior art, and realize high-precision spectral radiation joint calibration of the satellite-borne hyperspectral remote sensor.

[0006] The present invention provides a spectral radiation joint calibration method for a spaceborne hyperspectral remote sensor, comprising the following steps:

[0007] A spectral radiation joint calibration model is established based on an atmospheric radiation transmission simulation model and remote sensor observations; the spectral radiation joint calibration model is used to describe the distance matching quantitative relationship and the spectral angle matching quantitative relationship between the simulated apparent reflectance and the observed apparent reflectance;

[0008] The spectral radiation joint calibration model is solved iteratively to obtain the spectral radiation calibration parameters.

[0009] According to the spectral radiation joint calibration method of the spaceborne hyperspectral remote sensor provided by the present invention, the expression of the spectral radiation joint calibration model is:

[0010]

[0011] Among them, Δλ is the center wavelength offset, ΔF is the half-wave width offset, G is the absolute radiation calibration coefficient gain, B is the bias of the absolute radiation calibration coefficient; γ is the weight coefficient, is the observed value of the apparent reflectance at the entrance pupil of the jth band after convolution with the spectral response function of the hyperspectral remote sensor; is the simulated value of the apparent reflectance at the entrance pupil of the jth band after convolution with the spectral response function of the hyperspectral remote sensor, and N is the number of bands.

[0012] According to the spectral radiation joint calibration method of the spaceborne hyperspectral remote sensor provided by the present invention, the expression of the apparent reflectance observation value is:

[0013]

[0014] Among them, DN is the DN value actually observed by the spaceborne hyperspectral remote sensor, μ s is the cosine of the solar zenith angle, and E0 is the solar irradiance.

[0015] According to the spectral radiation joint calibration method of the satellite-borne hyperspectral remote sensor provided by the present invention, the apparent reflectance simulation value is obtained by convolution calculation of the ultra-high spectral radiance spectrum simulated by the atmospheric radiation transmission simulation model and the spectral response function of the hyperspectral remote sensor.

[0016] According to the spectral radiation joint calibration method of the spaceborne hyperspectral remote sensor provided by the present invention, the expression of the apparent reflectance simulation value is:

[0017]

[0018] Among them, λ1 is the starting wavelength, λ2 is the ending wavelength, ρ k The ultra-high spectral radiance simulated by the atmospheric radiation transfer simulation model, S j (λ) is the spectral response function of the satellite-borne hyperspectral remote sensor; the spectral response function of the satellite-borne hyperspectral remote sensor is obtained based on laboratory calibration.

[0019] According to the spectral radiation joint calibration method of the spaceborne hyperspectral remote sensor provided by the present invention, the spectral response function of the spaceborne hyperspectral remote sensor is expressed as:

[0020]

[0021] Among them, λ j is the center wavelength of the jth band calibrated by the laboratory, F j is the half-wave width of the jth band calibrated in the laboratory.

[0022] The present invention also provides a spectral radiation joint calibration device for a satellite-borne hyperspectral remote sensor, comprising:

[0023] A joint calibration model module is used to establish a spectral radiation joint calibration model based on an atmospheric radiation transmission simulation model and remote sensor observations; the spectral radiation joint calibration model is used to describe the distance matching quantitative relationship and the spectral angle matching quantitative relationship between the simulated apparent reflectance and the observed apparent reflectance;

[0024] The calibration module is used to iteratively solve the spectral radiation joint calibration model to obtain the spectral radiation calibration parameters.

[0025] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, a spectral radiation joint calibration method for a satellite-borne hyperspectral remote sensor as described in any one of the above-mentioned methods is implemented.

[0026] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method for joint calibration of spectral radiation of a space-borne hyperspectral remote sensor as described in any one of the above is implemented.

[0027] The present invention also provides a computer program product, comprising a computer program, which, when executed by a processor, implements any of the above-mentioned spectral radiation joint calibration methods for a space-borne hyperspectral remote sensor.

[0028] The spectral radiation joint calibration method and device of the spaceborne hyperspectral remote sensor provided by the present invention realizes the joint calibration of the spectrum and radiation calibration parameters of the spaceborne hyperspectral remote sensor by constructing a spectral radiation joint calibration model of the spaceborne hyperspectral remote sensor based on the atmospheric radiation transmission simulation model and the remote sensor observation value. Compared with the current hyperspectral payload spectrum and radiation independent or cyclic iteration calibration method, the present invention can simultaneously obtain the spectrum and radiation calibration parameters of the spaceborne hyperspectral remote sensor, and has obvious advantages in solving the coupling entanglement problem of the two in the process of spectrum and radiation calibration of the spaceborne hyperspectral remote sensor and improving the calibration accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the present invention or 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 creative work.

[0030] Figure 1 It is a schematic diagram of the overall process of the spectral radiation joint calibration method of the space-borne hyperspectral remote sensor provided by the present invention;

[0031] Figure 2 It is a schematic diagram of a model solution process of a spectral radiation joint calibration method for a spaceborne hyperspectral remote sensor provided by the present invention;

[0032] Figure 3 It is a structural schematic diagram of a spectral radiation joint calibration device for a satellite-borne hyperspectral remote sensor provided by the present invention;

[0033] Figure 4 It is a structural schematic diagram of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] Combine the following Figure 1-Figure 4 The present invention describes a spectral radiation joint calibration method and device for a satellite-borne hyperspectral remote sensor.

[0036] Figure 1 FIG. 1 is a schematic diagram of the overall process of the spectral radiation joint calibration method of the spaceborne hyperspectral remote sensor according to an embodiment of the present invention. Figure 1 As shown, it includes step 110 and step 120, specifically:

[0037] Step 110: establishing a spectral radiation joint calibration model based on the atmospheric radiation transmission simulation model and the remote sensor observation values; the spectral radiation joint calibration model is used to describe the distance matching quantitative relationship and the spectral angle matching quantitative relationship between the simulated apparent reflectance and the observed apparent reflectance;

[0038] Step 120, iteratively solve the spectral radiation joint calibration model to obtain spectral radiation calibration parameters.

[0039] In step 110 of the embodiment of the present invention, the simulated apparent reflectivity is the simulated apparent reflectivity data obtained by simulating the atmospheric radiation transmission process using a physics-based atmospheric radiation transmission simulation model. The atmospheric radiation transmission simulation model can be an existing model describing the atmospheric radiation transmission process, such as a 5S model, a 6S model, a LOWTRAN model, a MODTRAN model, and a FASCODE model, etc., or a model created using other methods to describe the atmospheric radiation transmission process. It can be understood that the simulated apparent reflectivity data of the embodiment of the present invention can be simulated using a single atmospheric radiation transmission simulation model, or can be simulated using multiple different atmospheric radiation transmission simulation models.

[0040] In the embodiment of the present invention, the expression of the spectral radiation joint calibration model is:

[0041]

[0042] Among them, Δλ is the center wavelength offset, ΔF is the half-wave width offset, G is the absolute radiation calibration coefficient gain, B is the bias of the absolute radiation calibration coefficient; γ is the weight coefficient, is the observed value of the apparent reflectance at the entrance pupil of the jth band after convolution with the spectral response function of the hyperspectral remote sensor; is the simulated value of the apparent reflectance at the entrance pupil of the jth band after convolution with the spectral response function of the hyperspectral remote sensor, and N is the number of bands.

[0043] In an embodiment of the present invention, the weight coefficient can be set according to the degree of attention paid by the spectral radiation joint calibration model to distance matching and spectral angle matching. For example, when the spectral radiation joint calibration model is required to pay equal attention to distance matching and spectral angle matching, γ can be set to 0.5. When the spectral radiation joint calibration model is required to pay more attention to the quantitative relationship of distance matching, γ can be set to a real number greater than 0.5 but less than 1. Conversely, when the spectral radiation joint calibration model is required to pay more attention to the quantitative relationship of spectral angle matching, γ can be set to a real number greater than 0 but less than 0.5.

[0044] Specifically, the expression of the apparent reflectance observation value is:

[0045]

[0046] Among them, DN is the DN value actually observed by the spaceborne hyperspectral remote sensor, μ s is the cosine of the solar zenith angle, and E0 is the solar irradiance.

[0047] The apparent reflectance simulation value is obtained by convolution calculation based on the ultra-high spectral radiance spectrum simulated by the atmospheric radiation transmission simulation model and the spectral response function of the hyperspectral remote sensor, and its expression is:

[0048]

[0049] Among them, λ1 is the starting wavelength, λ2 is the ending wavelength, ρ k The ultra-high spectral radiance simulated by the atmospheric radiation transfer simulation model, S j (λ) is the spectral response function of the spaceborne hyperspectral remote sensor; the spectral response function of the spaceborne hyperspectral remote sensor is obtained according to laboratory calibration, and its expression is:

[0050]

[0051] Among them, λ j is the center wavelength of the jth band calibrated by the laboratory, F j is the half-wave width of the jth band calibrated in the laboratory.

[0052] The embodiment of the present invention realizes decoupling in the process of spectral radiation joint calibration through the above-mentioned model design based on physical mechanism, so that the uncertainty factors in the spectral and radiation calibration process will not cause error accumulation due to the cyclic iterative solution process, and the requirements for input data are lower, which can improve the accuracy of spectral radiation joint calibration.

[0053] Figure 2 : is a schematic diagram of the model solution process of the spectral radiation joint calibration method of the space-borne hyperspectral remote sensor provided by the present invention, such as Figure 2 As shown, in step 120 of the embodiment of the present invention, the model can solve the spectral radiation joint calibration model by setting the optimization target and using a nonlinear optimization iteration method. Specifically, in the embodiment of the present invention, the optimization target is to minimize the difference between the apparent reflectance at the entrance pupil simulated by the atmospheric radiation transmission simulation model and the apparent reflectance at the entrance pupil observed by the hyperspectral remote sensor, and iteratively solve the spectral radiation joint calibration model to obtain the spectral radiation calibration parameters, including the following steps:

[0054] According to the preset conditions, it is determined whether the spectral radiation joint calibration model reaches the optimal solution; if the optimal solution is reached, the spectral radiation calibration parameters are output;

[0055] If the optimal solution is not reached, the input parameters for calculating the apparent reflectance observation value at the entrance pupil of the hyperspectral remote sensor (i.e., absolute radiation calibration parameters: gain G and bias B) and the input values ​​for simulation calculation of the atmospheric radiation transfer simulation model (i.e., spectral calibration parameters: center wavelength offset Δλ and half-wavewidth offset ΔF) are updated to reduce the gap between the apparent reflectance at the entrance pupil simulated by the atmospheric radiation transfer simulation model and the apparent reflectance at the entrance pupil observed by the hyperspectral remote sensor.

[0056] In a specific embodiment of the present invention, the preset condition may be the number of iterations or the difference between the apparent reflectance at the entrance pupil simulated by the atmospheric radiation transmission simulation model and the apparent reflectance at the entrance pupil observed by the hyperspectral remote sensor. That is, when the number of iterations reaches a first preset value, or the difference between the apparent reflectance at the entrance pupil simulated by the atmospheric radiation transmission simulation model and the apparent reflectance at the entrance pupil observed by the hyperspectral remote sensor is less than a second preset value, it is judged that the spectral radiation joint calibration model has reached the optimal solution.

[0057] In summary, the spectral radiation joint calibration method of the satellite-borne hyperspectral remote sensor of the embodiment of the present invention realizes the joint calibration of the spectrum and radiation calibration parameters of the satellite-borne hyperspectral remote sensor by constructing a spectral radiation joint calibration model of the satellite-borne hyperspectral remote sensor based on the atmospheric radiation transmission simulation model and the remote sensor observation value. Compared with the current hyperspectral payload spectrum and radiation independent or cyclic iteration calibration method, the present invention can simultaneously obtain the spectrum and radiation calibration parameters of the satellite-borne hyperspectral remote sensor, and has obvious advantages in solving the coupling and entanglement problem of the two in the process of spectrum and radiation calibration of the satellite-borne hyperspectral remote sensor and improving the calibration accuracy.

[0058] The spectral radiation joint calibration device of the satellite-borne hyperspectral remote sensor provided by the present invention is described below. The spectral radiation joint calibration device of the satellite-borne hyperspectral remote sensor described below and the spectral radiation joint calibration method of the satellite-borne hyperspectral remote sensor described above can be referenced to each other.

[0059] Figure 3 is a schematic diagram of the structure of a spectral radiation joint calibration device for a satellite-borne hyperspectral remote sensor according to an embodiment of the present invention. Figure 3 As shown, including:

[0060] A joint calibration model module 310 is used to establish a spectral radiation joint calibration model based on an atmospheric radiation transmission simulation model and remote sensor observations; the spectral radiation joint calibration model is used to describe a distance matching quantitative relationship and a spectral angle matching quantitative relationship between simulated apparent reflectance and observed apparent reflectance;

[0061] The calibration module 320 is used to iteratively solve the spectral radiation joint calibration model to obtain the spectral radiation calibration parameters.

[0062] It can be seen that the spectral radiation joint calibration device of the satellite-borne hyperspectral remote sensor of the embodiment of the present invention can construct a spectral radiation joint calibration model of the satellite-borne hyperspectral remote sensor based on the atmospheric radiation transmission simulation model and the remote sensor observation value, and realize the joint calibration of the spectrum and radiation calibration parameters of the satellite-borne hyperspectral remote sensor. Compared with the current hyperspectral payload spectrum and radiation independent or cyclic iteration calibration method, the present invention can simultaneously obtain the spectrum and radiation calibration parameters of the satellite-borne hyperspectral remote sensor, and has obvious advantages in solving the coupling and entanglement problem of the two in the process of spectrum and radiation calibration of the satellite-borne hyperspectral remote sensor and improving the calibration accuracy.

[0063] Figure 4 An example of a physical structure diagram of an electronic device is shown in FIG. Figure 4 As shown, the electronic device may include: a processor 410, a communication interface 420, a memory 430 and a communication bus 440, wherein the processor 410, the communication interface 420 and the memory 430 communicate with each other through the communication bus 440. The processor 410 may call the logic instructions in the memory 430 to execute the spectral radiation joint calibration method of the spaceborne hyperspectral remote sensor, including the following steps:

[0064] A spectral radiation joint calibration model is established based on an atmospheric radiation transmission simulation model and remote sensor observations; the spectral radiation joint calibration model is used to describe the distance matching quantitative relationship and the spectral angle matching quantitative relationship between the simulated apparent reflectance and the observed apparent reflectance;

[0065] The spectral radiation joint calibration model is solved iteratively to obtain the spectral radiation calibration parameters.

[0066] In addition, the logic instructions in the above-mentioned memory 830 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0067] On the other hand, the present invention further provides a computer program product, the computer program product includes a computer program, the computer program can be stored in a non-transitory computer-readable storage medium, when the computer program is executed by a processor, the computer can execute the spectral radiation joint calibration method of the spaceborne hyperspectral remote sensor provided by the above methods, including the following steps:

[0068] A spectral radiation joint calibration model is established based on an atmospheric radiation transmission simulation model and remote sensor observations; the spectral radiation joint calibration model is used to describe the distance matching quantitative relationship and the spectral angle matching quantitative relationship between the simulated apparent reflectance and the observed apparent reflectance;

[0069] The spectral radiation joint calibration model is solved iteratively to obtain the spectral radiation calibration parameters.

[0070] In another aspect, the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon, which is implemented when the computer program is executed by a processor to perform the spectral radiation joint calibration method of the spaceborne hyperspectral remote sensor provided by the above methods, including the following steps:

[0071] A spectral radiation joint calibration model is established based on an atmospheric radiation transmission simulation model and remote sensor observations; the spectral radiation joint calibration model is used to describe the distance matching quantitative relationship and the spectral angle matching quantitative relationship between the simulated apparent reflectance and the observed apparent reflectance;

[0072] The spectral radiation joint calibration model is solved iteratively to obtain the spectral radiation calibration parameters.

[0073] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0074] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0075] Finally, it should be noted that 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A spectral radiation joint calibration method for a spaceborne hyperspectral remote sensor, characterized in that: The following steps are involved: A spectral radiation joint calibration model is established based on an atmospheric radiation transmission simulation model and remote sensor observations; the spectral radiation joint calibration model is used to describe the distance matching quantitative relationship and the spectral angle matching quantitative relationship between the simulated apparent reflectance and the observed apparent reflectance; Iteratively solve the spectral radiation joint calibration model to obtain the spectral radiation calibration parameters; The expression of the spectral radiation joint calibration model is: Among them, Δλ is the center wavelength offset, Δf is the half-wave width offset, G is the absolute radiation calibration coefficient gain, B is the bias of the absolute radiation calibration coefficient; γ is the weight coefficient, is the observed value of the apparent reflectance at the entrance pupil of the jth band after convolution with the spectral response function of the hyperspectral remote sensor; is the simulated value of the apparent reflectance at the entrance pupil of the jth band after convolution with the spectral response function of the hyperspectral remote sensor, and N is the number of bands; The expression of the apparent reflectance observation value is: Among them, DN is the DN value actually observed by the spaceborne hyperspectral remote sensor, μ s is the cosine of the solar zenith angle, and E0 is the solar irradiance; Wherein, the simulated apparent reflectance value is obtained by convolution calculation based on the ultra-high spectral radiance spectrum simulated by the atmospheric radiation transmission simulation model and the spectral response function of the hyperspectral remote sensor; Wherein, the expression of the simulated value of apparent reflectance is: Among them, λ1 is the starting wavelength, λ2 is the ending wavelength, ρ k The ultra-high spectral radiance simulated by the atmospheric radiation transfer simulation model, S j (λ) is the spectral response function of the satellite-borne hyperspectral remote sensor; the spectral response function of the satellite-borne hyperspectral remote sensor is obtained based on laboratory calibration. The spectral response function of the satellite-borne hyperspectral remote sensor is expressed as follows: Among them, λ j is the center wavelength of the jth band calibrated by the laboratory, F j is the half-wave width of the jth band calibrated in the laboratory.

2. A spectral radiation joint calibration device for a satellite-borne hyperspectral remote sensor, characterized in that: The method for performing spectral radiation joint calibration of a spaceborne hyperspectral remote sensor as claimed in claim 1 comprises: A joint calibration model module is used to establish a spectral radiation joint calibration model based on an atmospheric radiation transmission simulation model and remote sensor observations; the spectral radiation joint calibration model is used to describe the distance matching quantitative relationship and the spectral angle matching quantitative relationship between the simulated apparent reflectance and the observed apparent reflectance; The calibration module is used to iteratively solve the spectral radiation joint calibration model to obtain the spectral radiation calibration parameters.

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