Stray light measuring device for imaging spectrometer and stray light correction method

Abstract

The invention discloses a stray light measuring device for an imaging spectrometer and a stray light correction method. The measuring device comprises a white light laser, a focusing system, a light splitting system, a collimation system, a pinhole diaphragm, an adjusting table and the imaging spectrometer. For the stray light problem of the imaging spectrometer, firstly, suppression is carried out from a design source, and measures such as stray light eliminating diaphragms are added; then a set of stray light correction system is designed, through the same set of device, two-dimensional stray light correction of the spectrum dimension and the space dimension of the area array detector can be achieved, repeated measurement of an experiment is avoided, the operation process is simplified, and the device and the process are simple and convenient. The method is suitable for stray light suppression and correction of the spectral dimension and the spatial dimension of the imaging spectrometer; the stray light diaphragm setting method and the stray light measuring device have important reference value for the space imaging load, and can provide technical support for improving the radiometric calibration precision.

Description

Technical Field

[0001] The present invention relates to the technical field of stray light correction of optical systems, and in particular to the field related to spectral and spatial dimension stray light suppression and correction of space-load imaging spectrometers, and specifically to a stray light measurement device and a stray light correction method for an imaging spectrometer. Background Art

[0002] Imaging spectrometers have been widely used in many fields, and their radiation calibration accuracy directly affects the measurement accuracy. Among the many factors that affect the radiation calibration accuracy of imaging spectrometers, stray light is a major source of error. Stray light not only affects the spectral dimension, causing the spectra of each wavelength to overlap chaotically, but also affects the DN value of each pixel radiation response, thereby affecting the radiation calibration accuracy; at the same time, stray light also affects the quality of space imaging. Therefore, stray light itself has become the main indicator for calibrating the quality performance of imaging spectrometers. Therefore, conducting research on two-dimensional stray light correction in the spectral dimension and spatial dimension of imaging spectrometers is of great significance to future aerial remote sensing payloads.

[0003] Stray light inside the instrument, whether in the spectral dimension or the spatial dimension, is a common problem in space remote sensing instruments. Stray light is mainly caused by the scattering caused by the non-ideal characteristics of optical elements, reflectors, slits, convex gratings, etc. and the high-order diffraction of the grating. In the early stage of optical design and processing, the design of stray light elimination apertures and light blocking rings can only suppress stray light to a certain extent, but cannot completely eliminate the impact of stray light on the detector signal. In the later stage, it is necessary to build an experimental device to perform stray light data correction on the entire imaging spectrometer to further reduce the impact of stray light on the data.

[0004] Currently, many documents and patents focus on correcting stray light in the spectral dimension of linear array non-imaging detectors, but lack methods and devices for correcting stray light in the spectral and spatial dimensions of planar array detectors used in imaging spectrometers. Summary of the invention

[0005] In view of the problem of spectral dimension and spatial dimension stray light correction of existing imaging hyperspectral imagers, the present invention provides a stray light measurement device and a stray light correction method for an imaging spectrometer, so as to achieve accurate and efficient measurement of stray light and correct the stray light in two dimensions, thereby reducing the impact of stray light.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] The invention discloses a stray light measuring device for an imaging spectrometer, which comprises: a white light laser, a focusing system, a light splitting system, a collimation system, a pinhole aperture, an imaging spectrometer and an adjustment platform;

[0008] A white light laser as a light source emits a parallel light beam, which passes through the focusing system and is focused at the incident slit of the light splitting system. The light splitting system then splits the focused parallel light beam and turns it into a single-wavelength light beam. The single-wavelength light beam passes through a coupler at the exit of the light splitting system and enters an optical fiber placed at the focal plane of the collimation system. After being collimated by the collimation system, a single-wavelength parallel light beam is output. After passing through the pinhole aperture at the exit of the collimation system, the single-wavelength parallel light beam becomes a single-wavelength parallel point source and enters the imaging spectrometer as incident light.

[0009] The position of the area array detector in the imaging spectrometer in the Y spatial direction is adjusted by an adjustment stage so that the incident light is imaged on the pixels of the spectral dimension and the spatial dimension of the area array detector, thereby measuring the stray light of the imaging spectrometer in the spectral dimension and the spatial dimension.

[0010] The stray light measuring device for an imaging spectrometer described in the present invention is also characterized in that:

[0011] The focusing system and the collimating system are mutually reversible optical path systems. The focusing system and the collimating system are transmission-type single convex lenses or lens groups, or reflection-type single off-axis parabolic lenses.

[0012] Furthermore, the spectroscopic system is a CT structure spectrometer that utilizes plane grating spectrometry, or a spectrometer system that utilizes prism, concave grating or convex grating spectrometry.

[0013] The stray light correction method for an imaging spectrometer of the present invention is characterized in that it is applied to the stray light measurement device and is performed according to the following steps:

[0014] Step 1: Measure the spectral stray light distribution matrix D n×n :

[0015] Step 1.1: Keep the imaging spectrometer in place and control the spectroscopic system to output wavelengths from λ0 to λ n The single wavelength beam is used to obtain the response value of the pixel in the area array detector, where the response value of the pixel in the i-th row and j-th column of the area array detector is recorded as M i,j , i is the number of rows of pixels in the array detector of the imaging spectrometer, j is the number of columns of pixels in the array detector of the imaging spectrometer; i, j∈[1,n]; n represents the dimension of the pixel in the array detector;

[0016] Step 1.2: The pixels of the imaging spectrometer array detector that respond to the single-wavelength beam and its adjacent pixels are recorded as the in-band pixels of the single-wavelength beam, and the remaining pixels are recorded as the out-band pixels of the single-wavelength beam;

[0017] If the pixel in the i-th row and j-th column belongs to the out-of-band area, then let the distribution function of the stray light of the pixel in the i-th row and j-th column in the spectral dimension be i,j is the response value M of the pixel in the spectral dimension of the pixel in the i-th row and j-th column in the out-of-band area i,j Divided by the sum of the response values ​​of all pixels in the in-band area on the spectral dimension, if the pixel in the i-th row and j-th column belongs to the in-band area pixel, let the distribution function of the stray light of the pixel in the i-th row and j-th column on the spectral dimension be d i,j is 0, thus obtaining the spectral stray light distribution matrix D n×n =[d i,j ] i,j=1,2,…,n ;

[0018] Step 2: Measure the spatial stray light distribution matrix E n×n :

[0019] Step 2.1: Select a monochromatic wavelength λ of the single-wavelength light beam and keep it unchanged, change the Y spatial dimension of the imaging spectrometer by adjusting the adjustment stage, and adjust the pitch angle of the imaging spectrometer, so that the lens of the imaging spectrometer moves from the initial 0 angle corresponding to the central field of view to the half field of view of θ angle in sequence, and obtain the spatial dimension Response pixels;

[0020] like Any of the response pixels Line If the pixels in the first column belong to the out-of-band area, then Line Distribution function of stray light in the spatial dimension of a column pixel The pixel in the out-of-band area Line The response value of the column pixel in the spatial dimension N i´,j´ Divided by the sum of the response values ​​of all pixels in the band in the spatial dimension, if the Line If the pixel column belongs to the in-band area pixel, then let Line Distribution function of stray light of pixel in spectral dimension is 0, thus obtaining the spatial dimensional stray light distribution matrix ;

[0021] Step 3: Use equation (1) to obtain the spectral stray light correction matrix B n×n ;

[0022] (1)

[0023] In formula (1), i,j for The response correction value of , and:

[0024] (2)

[0025] In formula (2), A is the identity matrix of the spectral dimension;

[0026] Using formula (3), we can get the spatial stray light correction matrix: ;

[0027] (3)

[0028] In formula (3), for The response correction value of , and:

[0029] (4)

[0030] In formula (4), is the identity matrix of the spatial dimension.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. The present invention measures the pinhole monochromatic parallel light beam through the same set of measuring devices, and converts the parallel light beam input by the white light laser into the pinhole monochromatic parallel light beam output through the construction of the entire optical path. The spectral line spread function (SLSF) is obtained by measuring the output of a single-wavelength beam, and the point spread function (PSF) is obtained by measuring the parallel light pinhole point source, and then the spectral dimension and spatial dimension stray light correction matrix are obtained, so as to perform two-dimensional stray light correction on the imaging spectrometer, reduce the influence of stray light on the results, thereby avoiding repeated experimental measurements, simplifying the operation process, and having a wide range of applications.

[0033] 2. The stray light measuring device of the present invention comprises a white light laser, a focusing system, a spectroscopic system, a collimation system, a pinhole aperture, an adjustment stage, and an imaging spectrometer. By measuring the pinhole monochromatic parallel light beam, the spectral line spread function (SLSF) and the point spread function (PSF) are obtained, and then the spectral dimension stray light correction matrix and the spatial dimension stray light correction matrix are obtained, so that the imaging spectrometer is corrected for stray light in two dimensions, reducing the influence of stray light. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a schematic diagram of a stray light measuring device for an imaging spectrometer of the present invention;

[0035] Figure 2 It is a schematic diagram of the working imaging mode of the imaging spectrometer;

[0036] Figure 3a This is a schematic diagram of the distribution of spectral stray light correction;

[0037] Figure 3b Schematic diagram of the spatial dimension stray light correction distribution;

[0038] Figure 4 is a schematic diagram of the correction method.

[0039] Markings in the figure: white light laser 1, focusing system 2, splitting system 3, collimation system 4, pinhole aperture 5, lens 6, imaging spectrometer 7, adjustment stage 8, vernier caliper 9. DETAILED DESCRIPTION

[0040] In this embodiment, a stray light measuring device for an imaging spectrometer is provided. Figure 1 As shown, it includes: a white light laser 1, a focusing system 2, a light splitting system 3, a collimation system 4, a pinhole aperture 5, an imaging spectrometer 7 and an adjustment stage 8;

[0041] The focusing system 2 and the collimating system 4 are optical path reversible systems. The focusing system 2 and the collimating system 4 are transmissive single convex lenses or lens groups, or reflective single off-axis parabolic lenses.

[0042] The spectroscopic system 3 is a CT structure spectrometer using a plane grating for spectrometry, or a spectrometer system using a prism, a concave grating or a convex grating for spectrometry; as long as the optical elements in the optical path are adjusted by a motor drive, a narrow spectral width, continuously adjustable monochromatic light can be output at the outlet.

[0043] Figure 2 As shown, the entire imaging spectrometer 7 is composed of a front real entrance pupil image side telecentric off-axis three-mirror, a rear Offner spectroscopic system, and a planar array detector.

[0044] After the incident light beam is split by the spectroscopic system 3, it is split in one dimension of the array detector, and each pixel corresponds to a different wavelength. This dimension is called the spectral dimension; the other dimension is used for Y field imaging, called the Y spatial dimension. When the instrument is working, it pushes and scans along the direction perpendicular to the slit, and synthesizes the n pictures of the push scan into the X spatial dimension, that is, the X spatial dimension is the number of pictures taken; taking a picture includes the spectral dimension and the Y spatial dimension.

[0045] The power of the white light laser 1 is continuously adjustable, and the size of the pinhole aperture 5 at the exit of the collimation system 4 is also continuously adjustable. The power of the white light laser 1 and the size of the pinhole aperture 5 can be adjusted by feedback according to the response of each pixel of the array detector; it is ensured that the response of the array detector is not saturated after each single wavelength light beam passes through the imaging spectrometer 7 and reaches the pixel, and the spatial dimension direction occupies a single row of pixels, or a small number of rows of pixels.

[0046] The white light laser 1 as the light source emits a parallel light beam, which passes through the focusing system 2 and is focused at the incident slit of the splitter system 3. The splitter system 3 then splits the focused parallel light beam and converts it into a single-wavelength light beam. The single-wavelength light beam output is to obtain a monochromatic spectral line source to characterize a specific wavelength, thereby obtaining a spectral line spread function (SLSF).

[0047] The single-wavelength light beam passes through the coupler at the exit of the spectroscopic system 3 and enters the optical fiber placed at the focal plane of the collimation system 4. After being collimated by the collimation system 4, a single-wavelength parallel light beam is output. The parallel light pinhole source output is to obtain the two-dimensional relative spatial response of the imaging spectrometer when measuring the pinhole source, thereby obtaining the point spread function (PSF).

[0048] After the single-wavelength parallel light beam passes through the pinhole aperture 5 at the exit of the collimation system 4, it becomes a single-wavelength parallel point source and enters the imaging spectrometer 7 as incident light; by adjusting the size of the pinhole aperture 5 at the exit of the collimation system 4, a single-wavelength parallel point source can be obtained.

[0049] The position of the area array detector in the imaging spectrometer 7 in the Y spatial direction is adjusted by adjusting the stage 8 so that the incident light is imaged on the pixels of the spectral dimension and the spatial dimension of the area array detector, thereby measuring the stray light of the imaging spectrometer 7 in the spectral dimension and the spatial dimension.

[0050] According to the distance L between the pinhole aperture 5 and the imaging spectrometer 7, and the field of view angle of the lens 6 of the imaging spectrometer 7, the moving distance of the imaging spectrometer 7 in the Y direction is calculated, and the imaging spectrometer 7 is adjusted using the adjustment table 8 according to the value of the vernier caliper 9 so that the pinhole point source is in different fields of view in the lens 6 of the imaging spectrometer 7.

[0051] When a parallel light beam enters the optical system and converges at a point, such an optical system is called a focusing system. On the contrary, when a light beam is emitted from a point source and finally emerges as parallel light through the optical system, such an optical system is called a collimating system.

[0052] In this embodiment, a stray light correction method for an imaging spectrometer 7 is applied to the above-mentioned stray light measurement device, such as Figure 3a , Figure 3b The diagrams shown here represent the schematic diagrams of spectral dimension stray light test and spatial dimension stray light test, where Figure 3a Where λ1 represents the wavelength corresponding to pixel 1 in the spectral dimension, λ x Represents the wavelength corresponding to the pixel x in the spectral dimension, λ m Represents the wavelength corresponding to the pixel m in the spectral dimension, λ n Represents the wavelength corresponding to the nth pixel in the spectral dimension. Figure 3b Y represents the corresponding spatial dimension, Y0 represents the spatial dimension corresponding to the spatial dimension of the Y center field of view corresponding to the spatial dimension of pixel 0, and Yx Represents the spatial dimension corresponding to a certain x field of view of Y, the spatial dimension corresponding to the pixel number x, Y m represents the spatial dimension corresponding to the m-th pixel of a certain m-field of view, Y n Represents the spatial dimension corresponding to the nth pixel of a certain n-field of view of Y. The single-wavelength parallel light output is to obtain a monochromatic spectral line source to characterize a specific wavelength, thereby obtaining a spectral line spread function (SLSF). The parallel light pinhole source output is to obtain the two-dimensional relative spatial response of the imaging spectrometer 7 when measuring the pinhole source, thereby obtaining a point spread function (PSF).

[0053] Spectral stray light correction is to correct the stray light relationship between pixels in the spectral dimension; spatial stray light correction is to correct the stray light relationship between pixels in the Y spatial dimension. For high-precision imaging spectrometers, it is necessary to correct stray light in two dimensions to reduce the impact of stray light on the results.

[0054] like Figure 4 As shown, the present invention realizes simultaneous correction of two dimensions through the same device and the same experiment. By adjusting the output monochromatic wavelength of the spectroscopic system 3 and adjusting the position of the imaging spectrometer 7 in the Y spatial direction by adjusting the stage 8, the spectral dimension of the imaging spectrometer and the spatial dimension stray light distribution function in the Y field of view are measured to construct the spectral dimension stray light distribution matrix D n×n and the spatial stray light distribution matrix E n×n ; According to the stray light distribution matrix, the spectral stray light correction matrix B is obtained respectively n×n and the spatial stray light correction matrix C n×n , to achieve out-of-band stray light correction for the measurement signal. Specifically, the method is carried out in the following steps:

[0055] Step 1: Measure the spectral stray light distribution matrix D n×n :

[0056] Step 1.1: Keep the imaging spectrometer 7 in place, and control the spectroscopic system 3 to output wavelengths from λ0 to λ1 at regular intervals, for example, every 10 nm. n The single wavelength beam is used to obtain the response value of the pixel in the area array detector. The imaging spectrometer 7 uses an area array detector. For an area array detector with n*n pixels, the area array detector is regarded as composed of n linear array detectors, each linear array detector has n pixels, and each monochromatic spectrum output by the spectroscopic system 3 can be measured to obtain an n-dimensional column vector. The response value of the pixel in the i-th row and j-th column of the area array detector is recorded as M i,j , i is the number of rows of pixels in the array detector of the imaging spectrometer 7, j is the number of columns of pixels in the array detector of the imaging spectrometer 7; i, j∈[1,n]; n represents the dimension of the pixels in the array detector;

[0057] Step 1.2: The pixel and its adjacent pixels of the array detector of the imaging spectrometer 7 that respond to the single-wavelength beam are recorded as the in-band pixels of the single-wavelength beam, and the remaining pixels are recorded as the out-band pixels of the single-wavelength beam;

[0058] If the pixel in the i-th row and j-th column belongs to the out-of-band area, then let the distribution function of the stray light of the pixel in the i-th row and j-th column in the spectral dimension be i,j is the response value M of the pixel in the spectral dimension of the pixel in the i-th row and j-th column in the out-of-band area i,j Divided by the sum of the response values ​​of all pixels in the in-band area on the spectral dimension, if the pixel in the i-th row and j-th column belongs to the in-band area pixel, let the distribution function of the stray light of the pixel in the i-th row and j-th column on the spectral dimension be d i,j is 0, thus obtaining the spectral stray light distribution matrix D n×n =[d i,j ] i,j=1,2,…,n ; The formula is as follows:

[0059]

[0060] Spectral stray light distribution matrix D n×n It is the core of out-of-band stray light correction. Each column represents the out-of-band stray light distribution of a fixed index wavelength spectrum for each pixel, and each row represents the stray light distribution of each index wavelength for a fixed pixel.

[0061] Step 2: Measure the spatial stray light distribution matrix E n×n :

[0062] Step 2.1: Select a monochromatic wavelength λ of the single-wavelength light beam and keep it unchanged, change the Y spatial dimension of the imaging spectrometer 7 by adjusting the adjustment stage 8, and adjust the pitch angle of the imaging spectrometer 7, so that the lens of the imaging spectrometer 7 moves from the initial 0 angle corresponding to the central field of view to the half field of view θ angle in sequence, and obtain the spatial dimension Response pixels;

[0063] like Any of the response pixels Line If the pixels in the first column belong to the out-of-band area, then Line Distribution function of stray light in the spatial dimension of a column pixel The pixel in the out-of-band area Line The response value of the column pixel in the spatial dimension N i´,j´ Divided by the sum of the response values ​​of all pixels in the band in the spatial dimension, if the Line If the pixel column belongs to the in-band area pixel, then let Line Distribution function of stray light of pixel in spectral dimension is 0, thus obtaining the spatial dimensional stray light distribution matrix ; The formula is as follows:

[0064]

[0065] Spatial stray light distribution matrix E n×n It is the core of the spatial dimension out-of-band stray light correction. Each column represents the out-of-band stray light distribution of the aperture point source for each pixel in a certain fixed Y spatial dimension corresponding to the field of view; each row represents the stray light distribution of each Y spatial dimension corresponding to the field of view for a certain fixed pixel.

[0066] Step 3: Solve the spectral stray light correction matrix B n×n and the spatial dimensional stray light correction matrix C n´×n´ , including: the spectral stray light distribution matrix D obtained according to step 1 and step 2 n×n , using formula (1) to obtain the spectral stray light correction matrix B n×n ;

[0067] (1)

[0068] In formula (1), i,j for The response correction value of , and:

[0069] (2)

[0070] In formula (2), A is the identity matrix of the spectral dimension;

[0071] The spatial stray light distribution matrix E obtained from step 1 and step 2 n´×n´ , using formula (3) to obtain the spatial stray light correction matrix ;

[0072] (3)

[0073] In formula (3), for The response correction value of , and:

[0074] (4)

[0075] In formula (4), is the identity matrix of the spatial dimension.

[0076] Since the obtained spectral dimension and spatial dimension stray light correction matrices are independent, one represents the spectral dimension stray light distribution characteristics of the detector, and the other represents the spatial dimension stray light distribution characteristics of the instrument Y field of view. Both are indispensable for the stray light correction of imaging spectrometers. Therefore, in practical applications, the spectral dimension and spatial dimension stray light correction matrices need to be used to correct the detector measurement values ​​respectively to obtain the actual true signal value.

[0077] If the uniformity of the entire detector and the consistency of each pixel are good, or the consistency of each pixel has been corrected. When performing stray light correction on the spectral dimension, it can be regarded as consisting of n linear array detectors with consistent performance. It is only necessary to repeatedly correct the n rows of the entire detector using a certain row of the stray light correction matrix obtained in the spectral dimension in step 3 above. When performing stray light correction on the spatial dimension, it is only necessary to repeatedly correct the n columns of the entire detector using a certain column of the stray light correction matrix obtained in the spatial dimension in step 4 above.

[0078] If the uniformity of the entire detector and the consistency of each pixel are good or the consistency of each pixel has been corrected, then when performing stray light correction on the spectral dimension, only a certain row of the stray light correction matrix obtained in the spectral dimension of step 1 is repeatedly corrected on the n rows of the entire detector; when performing stray light correction on the spatial dimension, only a certain column of the stray light correction matrix obtained in the spatial dimension of step 2 is repeatedly corrected on the n columns of the entire detector one by one.

[0079] If the uniformity consistency of each pixel of the entire detector is not corrected, when the stray light correction is performed on the spectral dimension, the spectral dimension stray light distribution matrix of step 1 is measured one by one to obtain the spectral dimension stray light matrix of n linear array detectors, and then the stray light correction matrix measured in each row is used to correct the corresponding row; when the stray light correction is performed on the spatial dimension, the spatial dimension stray light distribution matrix of step 2 is measured one by one to obtain the spectral dimension stray light matrix of n linear array detectors, and then the stray light correction matrix measured in each column is used to correct the corresponding column.

[0080] In summary, the present invention provides a stray light measurement device and correction method for an imaging spectrometer. Through the same set of measuring devices, a pinhole monochromatic parallel light beam is measured to obtain a spectral line spread function (SLSF) and a point spread function (PSF), and then the spectral dimension and spatial dimension stray light correction matrix are obtained, thereby performing two-dimensional stray light correction on the imaging spectrometer to reduce the impact of stray light.

Claims

1. A stray light measuring device for an imaging spectrometer, characterized in that: include: White light laser (1), focusing system (2), light splitting system (3), collimation system (4), pinhole aperture (5), imaging spectrometer (7) and adjustment stage (8); A white light laser (1) as a light source emits a parallel light beam, which passes through the focusing system (2) and is focused at the incident slit of the light splitting system (3), and then the light splitting system (3) splits the focused parallel light beam and converts it into a single-wavelength light beam. The single-wavelength light beam passes through a coupler at the exit of the light splitting system (3) and enters an optical fiber placed at the focal plane of the collimating system (4), and after being collimated by the collimating system (4), a single-wavelength parallel light beam is output; after the single-wavelength parallel light beam passes through a pinhole aperture (5) at the exit of the collimating system (4), it becomes a single-wavelength parallel point source and enters an imaging spectrometer (7) as incident light; The position of the area array detector in the imaging spectrometer (7) in the Y spatial direction is adjusted by means of an adjustment platform (8) so that the incident light is imaged on the pixels of the spectral dimension and the spatial dimension of the area array detector, thereby measuring the stray light of the imaging spectrometer (7) in the spectral dimension and the spatial dimension.

2. The stray light measuring device for an imaging spectrometer according to claim 1, characterized in that: The focusing system (2) and the collimating system (4) are mutually optically reversible systems. The focusing system (2) and the collimating system (4) are transmission-type single convex lenses or lens groups, or reflection-type single off-axis parabolic lenses.

3. The stray light measuring device for an imaging spectrometer according to claim 1, characterized in that: The spectroscopic system (3) is a CT structure spectrometer that utilizes plane grating spectrometry, or a spectrometer system that utilizes prisms, concave gratings, or convex gratings for spectrometry.

4. A stray light correction method for an imaging spectrometer, characterized in that: The method is applied to the stray light measuring device as claimed in claim 1 and is performed in the following steps: Step 1: Measure the spectral stray light distribution matrix D n×n : Step 1.1: Keep the imaging spectrometer (7) in place and control the spectroscopic system (3) to output wavelengths from λ0 to λ n The single wavelength beam is used to obtain the response value of the pixel in the area array detector, where the response value of the pixel in the i-th row and j-th column of the area array detector is recorded as M i,j , i is the number of rows of pixels in the array detector of the imaging spectrometer (7), j is the number of columns of pixels in the array detector of the imaging spectrometer (7); i, j∈[1,n]; n represents the dimension of the pixels in the array detector; Step 1.2: Record the pixel of the array detector of the imaging spectrometer (7) that responds to the single-wavelength beam and its adjacent pixels as the in-band pixel of the single-wavelength beam, and record the remaining pixels as the out-band pixel of the single-wavelength beam; If the pixel in the i-th row and j-th column belongs to the out-of-band area, then let the distribution function of the stray light of the pixel in the i-th row and j-th column in the spectral dimension be i,j is the response value M of the pixel in the spectral dimension of the pixel in the i-th row and j-th column in the out-of-band area i,j Divided by the sum of the response values ​​of all pixels in the in-band area on the spectral dimension, if the pixel in the i-th row and j-th column belongs to the in-band area pixel, let the distribution function of the stray light of the pixel in the i-th row and j-th column on the spectral dimension be d i,j is 0, thus obtaining the spectral stray light distribution matrix D n×n =[d i,j ] i,j=1,2,…,n ; Step 2: Measure the spatial stray light distribution matrix E n×n : Step 2.1: Select a monochromatic wavelength λ of the single-wavelength light beam and keep it unchanged, change the Y spatial dimension of the imaging spectrometer (7) by adjusting the adjustment stage (8), and adjust the pitch angle of the imaging spectrometer (7), so that the lens of the imaging spectrometer (7) moves from the initial 0 angle corresponding to the central field of view to the half field of view θ angle in sequence, and obtain the spatial dimension Response pixels; like Any of the response pixels Line If the pixels in the first column belong to the out-of-band area, then Line Distribution function of stray light in the spatial dimension of a column pixel The pixel in the out-of-band area Line The response value of the column pixel in the spatial dimension N i´,j´ Divided by the sum of the response values ​​of all pixels in the band in the spatial dimension, if the Line If the pixel column belongs to the in-band area pixel, then let Line Distribution function of stray light of pixel in spectral dimension is 0, thus obtaining the spatial dimensional stray light distribution matrix ; Step 3: Use equation (1) to obtain the spectral stray light correction matrix B n×n ; (1) In formula (1), i,j for The response correction value of , and: (2) In formula (2), A is the identity matrix of the spectral dimension; Using formula (3), we can get the spatial stray light correction matrix: ; (3) In formula (3), for The response correction value of , and: (4) In formula (4), is the identity matrix of the spatial dimension.

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