A stray light measurement device and stray light correction method for an imaging spectrometer

Abstract

This invention discloses a stray light measurement device and a stray light correction method for imaging spectrometers. The measurement device includes a white light laser, a focusing system, a beam splitting system, a collimation system, a pinhole aperture, an adjustment stage, and an imaging spectrometer. Addressing the stray light problem in imaging spectrometers, the invention first suppresses stray light at its source by incorporating measures such as a stray light elimination aperture. Then, a stray light correction system is designed. Using the same device, two-dimensional stray light correction can be achieved for both the spectral and spatial dimensions of the array detector, avoiding repeated experimental measurements and simplifying the operation process. This invention is applicable to stray light suppression and correction in the spectral and spatial dimensions of imaging spectrometers. The stray light aperture setting method and stray light measurement device have important reference value for space imaging payloads and can provide technical support for improving radiometric calibration accuracy.

Description

Technical Field

[0001] This invention relates to the field of stray light correction technology for optical systems, and more particularly to the field of stray light suppression and correction in the spectral and spatial dimensions of space payload imaging spectrometers. Specifically, it relates to a stray light measurement device and a stray light correction method for imaging spectrometers. Background Technology

[0002] Imaging spectrometers are widely used in various fields, and their radiometric calibration accuracy directly affects measurement accuracy. Among the many factors affecting the radiometric calibration accuracy of imaging spectrometers, stray light is a major source of error. Stray light not only affects the spectral dimension, causing spectral overlap and disorder at different wavelengths, but also affects the DN value of the radiometric response of each pixel, thus impacting radiometric calibration accuracy. Simultaneously, stray light also affects the quality of spatial imaging. Therefore, stray light itself has become a key indicator for verifying the quality performance of imaging spectrometers. Thus, conducting research on two-dimensional stray light correction in both the spectral and spatial dimensions of imaging spectrometers is of great significance for future airborne remote sensing payloads.

[0003] Stray light, whether spectral or spatial, is a common problem in space remote sensing instruments. Stray light is mainly caused by the non-ideal characteristics of optical elements, mirrors, slits, convex gratings, and scattering due to higher-order diffraction of the gratings. Early optical design and fabrication processes, including the design of stray light suppression apertures and baffle rings, can only suppress stray light to a certain extent, not completely eliminate its influence on the detector signal. Later experimental setups are needed 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 there is a lack of methods and devices for correcting stray light in both the spectral and spatial dimensions of area array detectors used in imaging spectrometers. Summary of the Invention

[0005] To address the problem of stray light correction in the spectral and spatial dimensions of existing imaging hyperspectral imagers, this invention provides a stray light measurement device and a stray light correction method for imaging spectrometers, aiming to achieve accurate and efficient measurement of stray light and to correct stray light in two dimensions, thereby reducing the impact of stray light.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] The present invention provides a stray light measurement device for an imaging spectrometer, characterized in that it comprises: a white light laser, a focusing system, a beam splitting system, a collimation system, a pinhole aperture, an imaging spectrometer, and an adjustment stage;

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

[0009] By adjusting the position of the area array detector in the imaging spectrometer in the Y-space direction using the adjustment stage, the incident light is imaged on the pixels of the area array detector in both the spectral and spatial dimensions, thereby enabling the measurement of stray light in the spectral and spatial dimensions of the imaging spectrometer.

[0010] The stray light measurement device for an imaging spectrometer described in this invention is also characterized in that...

[0011] The focusing system and the collimating system are reversible optical paths. The focusing system and the collimating system are either transmissive single convex lenses or lens groups, or reflective single off-axis parabolic lenses.

[0012] Furthermore, the spectral system is a CT structure spectrometer that uses a planar grating for spectral dispersion, or a spectrometer system that uses a prism, a concave grating, or a convex grating for spectral dispersion.

[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 stationary and control the spectral dispersive system to sequentially output wavelengths from λ0 to λ1. n A single-wavelength beam is used to obtain the response value of a 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 denoted as M. i,j , i is the number of rows of pixels in the area array detector of the imaging spectrometer, j is the number of columns of pixels in the area array detector of the imaging spectrometer; i, j∈[1,n]; n represents the dimension of pixels in the area array detector;

[0016] Step 1.2: The pixels that respond to the single-wavelength beam by the area array detector of the imaging spectrometer and their adjacent pixels are recorded as the in-band region pixels of the single-wavelength beam, and the remaining pixels are recorded as the out-of-band region 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 region, then let the stray light distribution function d of the pixel in the i-th row and j-th column in the spectral dimension be... i,j M is the response value M of the pixel in the i-th row and j-th column of the out-of-band region in the spectral dimension. i,j Divide by the sum of the spectral response values ​​of all pixels in the in-band region. If the pixel in the i-th row and j-th column belongs to the in-band region, then let the stray light distribution function d of the pixel in the i-th row and j-th column in the spectral dimension be... i,j The value 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 beam and keep it constant. Change the Y-dimensional space 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 sequentially from the initial 0 angle corresponding to the central field of view to the half field of view of angle θ, and obtain the spatial dimension. Each response pixel;

[0020] like Any of the response pixels in the nth response cell Line 1 If a column cell belongs to an out-of-band region cell, then let the first cell be... Line 1 Distribution function of stray light in the spatial dimension of a column pixel For the out-of-band region pixels Line 1 The response value N of a column cell in the spatial dimension i´,j´ Divide by the sum of the response values ​​of all cells in the in-band region in the spatial dimension, if the first... Line 1 If a column cell belongs to an in-band region cell, then let Line 1 Distribution function of stray light in the spectral dimension of a pixel The value is 0, thus obtaining the spatial stray light distribution matrix. ;

[0021] Step 3: Obtain the spectral stray light correction matrix B using equation (1). n×n ;

[0022] (1)

[0023] In equation (1), i,j for The response correction value is:

[0024] (2)

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

[0026] The spatial stray light correction matrix is ​​obtained using equation (3). ;

[0027] (3)

[0028] In equation (3), for The response correction value is:

[0029] (4)

[0030] In equation (4), It is the identity matrix in spatial dimension.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] 1. This invention uses the same set of measuring devices to measure a pinhole monochromatic parallel beam. By constructing the entire optical path, the parallel beam input from the white laser is converted into a pinhole monochromatic parallel beam output. The spectral line spread function (SLSF) is obtained by measuring the single-wavelength beam output, and the point spread function (PSF) is obtained by measuring the parallel light pinhole point source. Then, the stray light correction matrices in the spectral and spatial dimensions are obtained, thereby performing stray light correction on the imaging spectrometer in two dimensions. This reduces the influence of stray light on the results, avoids repeated experimental measurements, simplifies the operation process, and has a wide range of applications.

[0033] 2. The stray light measurement device of this invention includes a white light laser, a focusing system, a beam splitting system, a collimation system, a pinhole aperture, an adjustment stage, and an imaging spectrometer. By measuring the pinhole monochromatic parallel beam, the spectral line spread function (SLSF) and point spread function (PSF) are obtained. Then, the spectral dimension stray light correction matrix and the spatial dimension stray light correction matrix are obtained, thereby performing stray light correction on the imaging spectrometer in two dimensions and reducing the influence of stray light. Attached Figure Description

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

[0035] Figure 2 This is a schematic diagram of the working imaging modes of an imaging spectrometer;

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

[0037] Figure 3b This is a schematic diagram of the spatial stray light correction distribution;

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

[0039] The diagram is labeled as follows: 1. White laser; 2. Focusing system; 3. Beam splitting system; 4. Collimation system; 5. Pinhole aperture; 6. Lens; 7. Imaging spectrometer; 8. Adjustment stage; 9. Vernier caliper. Detailed Implementation

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

[0041] Among them, focusing system 2 and collimating system 4 are optically reversible systems. Focusing system 2 and collimating system 4 are either transmissive single convex lenses or lens groups, or reflective single off-axis parabolic lenses.

[0042] The spectral system 3 is a CT structure spectrometer that uses a planar grating for spectral dispersion, or a spectrometer system that uses a prism, concave grating, or convex grating for spectral dispersion; as long as the optical elements in the optical path are adjusted by a motor drive, a narrow spectral width and continuously adjustable monochromatic light can be output at the exit.

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

[0044] After the incident beam is split into three parts by the beam splitting system, it is further split in one dimension of the array detector, with each pixel corresponding to a different wavelength. This dimension is called the spectral dimension. The other dimension is used for Y-field imaging and is called the Y-space dimension. When the instrument is working, it sweeps along the direction of the vertical slit, and the n images taken by the sweeping are combined to form the X-space dimension. That is, the X-space dimension is the number of images taken. A single image contains both the spectral dimension and the Y-space dimension.

[0045] The power of the white 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 laser 1 and the size of the pinhole aperture 5 can be adjusted based on the response of each pixel of the array detector, ensuring that the response of each single-wavelength beam is not saturated after it reaches the pixel through the imaging spectrometer 7, and that the spatial dimension occupies a single row of pixels, or a small number of rows of pixels.

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

[0047] A single-wavelength beam passes through the coupler at the exit of the beam splitting 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 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 passing through the pinhole aperture 5 at the exit of the collimation system 4, the single-wavelength parallel beam 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] By adjusting the position of the area array detector in the imaging spectrometer 7 in the Y-space direction using the adjustment stage 8, the incident light is imaged on the pixels of the spectral and spatial dimensions of the area array detector, thereby measuring stray light in the spectral and spatial dimensions of the imaging spectrometer 7.

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

[0051] An optical system is a focusing system when a parallel beam of light enters the system and converges to a single point; conversely, an optical system is a collimating system when a diverging beam of light originates from a point source and exits as parallel light.

[0052] In this embodiment, a stray light correction method for the imaging spectrometer 7 is applied to the aforementioned stray light measurement device, such as... Figure 3a , Figure 3b The diagrams shown represent schematic representations of spectral stray light testing and spatial stray light testing, respectively. Figure 3a In this context, λ1 represents the wavelength corresponding to pixel number 1 in the spectral dimension, and λ x λ represents the wavelength corresponding to the x-th pixel in the spectral dimension. m λ represents the wavelength corresponding to the m-th pixel in the spectral dimension. n This represents the wavelength corresponding to pixel n in the spectral dimension. Figure 3b In this context, Y represents the corresponding spatial dimension, Y0 represents the spatial dimension corresponding to pixel 0 in the central field of view of Y, and Y represents the spatial dimension of pixel 0.x This represents the spatial dimension of pixel x corresponding to a certain field of view of Y. m This represents the spatial dimension corresponding to the m-th pixel in a certain m-field of view of Y. n This represents the spatial dimension corresponding to the nth pixel in a certain n-field of view of Y. Single-wavelength parallel light output is used to obtain a monochromatic spectral line source to characterize a specific wavelength, thereby obtaining the spectral line spread function (SLSF). Parallel light pinhole source output is used to obtain the two-dimensional relative spatial response of the imaging spectrometer 7 when measuring the pinhole source, thereby obtaining the point spread function (PSF).

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

[0054] like Figure 4 As shown, this invention achieves simultaneous correction in two dimensions using the same device and the same experiment. By adjusting the monochromatic wavelength output by the spectrophotometer 3 and adjusting the position of the imaging spectrometer 7 in the Y-space direction by the adjustment stage 8, the spectral dimension and the spatial dimension stray light distribution function within the Y-field of view of the imaging spectrometer are measured, and the spectral dimension stray light distribution matrix D is constructed. n×n With the spatial stray light distribution matrix E n×n Based on the stray light distribution matrix, the spectral dimension stray light correction matrix B is obtained respectively. n×n With spatial stray light correction matrix C n×n This method achieves out-of-band stray light correction for the measurement signal. Specifically, it proceeds as follows:

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

[0056] Step 1.1: Keep the imaging spectrometer 7 stationary, and use the computer to control the spectral dispersive 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 n*n pixel area array detector, it is considered as composed of n linear array detectors, each with n pixels. Each monochromatic spectrum output by the spectrometer 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 denoted as M. i,j , i is the number of rows of pixels in the area array detector of the imaging spectrometer 7, j is the number of columns of pixels in the area array detector of the imaging spectrometer 7; i, j∈[1,n]; n represents the dimension of pixels in the area array detector;

[0057] Step 1.2: The pixels that respond to the single-wavelength beam by the area array detector of the imaging spectrometer 7 and their adjacent pixels are recorded as the in-band region pixels of the single-wavelength beam, and the remaining pixels are recorded as the out-of-band region 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 region, then let the stray light distribution function d of the pixel in the i-th row and j-th column in the spectral dimension be... i,j M is the response value M of the pixel in the i-th row and j-th column of the out-of-band region in the spectral dimension. i,j Divide by the sum of the spectral response values ​​of all pixels in the in-band region. If the pixel in the i-th row and j-th column belongs to the in-band region, then let the stray light distribution function d of the pixel in the i-th row and j-th column in the spectral dimension be... i,j The value is 0, thus obtaining the spectral stray light distribution matrix D. n×n =[d i,j ] i,j=1,2,…,n The formula is expressed 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 of it represents the out-of-band stray light distribution of a certain fixed index wavelength spectrum for each pixel, and each row represents the stray light distribution of each index wavelength for a certain 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 beam and keep it constant. Change the Y-dimensional space 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 of θ angle, and obtain the spatial dimension. Each response pixel;

[0063] like Any of the response pixels in the nth response cell Line 1 If a column cell belongs to an out-of-band region cell, then let the first cell be... Line 1 Distribution function of stray light in the spatial dimension of a column pixel For the out-of-band region pixels Line 1 The response value N of a column cell in the spatial dimension i´,j´ Divide by the sum of the response values ​​of all cells in the in-band region in the spatial dimension, if the first... Line 1 If a column cell belongs to an in-band region cell, then let Line 1 Distribution function of stray light in the spectral dimension of a pixel The value is 0, thus obtaining the spatial stray light distribution matrix. The formula is expressed as follows:

[0064]

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

[0066] Step 3: Solve for the spectral stray light correction matrix B n×n And spatial stray light correction matrix C n´×n´ This includes: the spectral stray light distribution matrix D obtained from steps 1 and 2. n×n The spectral stray light correction matrix B is obtained using equation (1). n×n ;

[0067] (1)

[0068] In equation (1), i,j for The response correction value is:

[0069] (2)

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

[0071] Based on the spatial stray light distribution matrix E obtained in steps 1 and 2 n´×n´ The spatial stray light correction matrix is ​​obtained using equation (3). ;

[0072] (3)

[0073] In equation (3), for The response correction value is:

[0074] (4)

[0075] In equation (4), It is the identity matrix in spatial dimension.

[0076] Since the obtained spectral and spatial stray light correction matrices are independent—one representing the stray light distribution characteristics in the detector's spectral dimension and the other representing the stray light distribution characteristics in the instrument's Y-field of view's spatial dimension—both are indispensable for stray light correction in imaging spectrometers. Therefore, in practical applications, the spectral and spatial stray light correction matrices need to be used separately to correct the detector measurements to obtain the actual true signal values.

[0077] If the overall uniformity of the detector and the consistency of each pixel are good, or if the consistency of each pixel has already been corrected, then when performing stray light correction in the spectral dimension, it can be considered as consisting of n linear detectors with consistent performance. Simply repeat the stray light correction matrix obtained in step 3 (spectral dimension) to correct all n rows of the entire detector. When performing stray light correction in the spatial dimension, simply repeat the stray light correction matrix obtained in step 4 (spatial dimension) to correct all n columns of the entire detector one by one.

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

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

[0080] In summary, this invention provides a stray light measurement device and correction method for an imaging spectrometer. By using the same measurement device to measure a pinhole monochromatic parallel beam, the spectral line spread function (SLSF) and point spread function (PSF) are obtained. Then, stray light correction matrices in the spectral and spatial dimensions are obtained, thereby performing stray light correction on the imaging spectrometer in two dimensions and reducing the influence of stray light.

Claims

1. A stray light correction method for an imaging spectrometer, applied in a stray light measurement device, wherein the stray light measurement device comprises: White laser (1), focusing system (2), beam splitting system (3), collimation system (4), pinhole aperture (5), imaging spectrometer (7), and adjustment stage (8); The white laser (1), which serves as the light source, emits a parallel beam. The parallel beam passes through the focusing system (2) and is focused at the entrance slit of the beam splitting system (3). The beam splitting system (3) then splits the focused parallel beam into a single-wavelength beam. The single-wavelength beam passes through the coupler at the exit of the beam splitting 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), it outputs a single-wavelength parallel beam. The single-wavelength parallel beam passes through the pinhole aperture (5) at the exit of the collimation system (4) and becomes a single-wavelength parallel point source, which then enters the imaging spectrometer (7) as incident light. The position of the area array detector in the imaging spectrometer (7) in the Y-space direction is adjusted by adjusting the stage (8) so that the incident light is imaged on the pixels of the spectral and spatial dimensions of the area array detector, thereby measuring the stray light in the spectral and spatial dimensions of the imaging spectrometer (7); characterized in that the stray light correction method is performed according to the following steps: Step 1: Measure the spectral stray light distribution matrix D n×n : Step 1.1: Keep the imaging spectrometer (7) stationary and control the spectral dispersive system (3) to output wavelengths from λ0 to λ1 in sequence. n A single-wavelength beam is used to obtain the response value of a 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 denoted as M. i,j i is the row number of the pixel in the area array detector of the imaging spectrometer (7), j is the column number of the pixel in the area array detector of the imaging spectrometer (7); i, j∈[1,n]; n represents the dimension of the pixel in the area array detector; Step 1.2: The pixels that respond to the single-wavelength beam by the area array detector of the imaging spectrometer (7) and their adjacent pixels are recorded as the in-band region pixels of the single-wavelength beam, and the remaining pixels are recorded as the out-of-band region pixels of the single-wavelength beam. If the pixel in the i-th row and j-th column belongs to the out-of-band region, then let the stray light distribution function d of the pixel in the i-th row and j-th column in the spectral dimension be... i,j M is the response value of the pixel in the i-th row and j-th column of the out-of-band region in the spectral dimension. i,j Divide by the sum of the spectral response values ​​of all pixels in the in-band region. If the pixel in the i-th row and j-th column belongs to the in-band region, then let the stray light distribution function d of the pixel in the i-th row and j-th column in the spectral dimension be... i,j The value 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 a single-wavelength beam and keep it constant. Change the Y-dimensional space 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 of θ angle, and obtain the spatial dimension. Each response pixel; like Any of the response pixels in the nth response cell Line number If a column cell belongs to an out-of-band region cell, then let the first cell be... Line number Distribution function of stray light in the spatial dimension of a column pixel For the out-of-band region pixels Line number The response value N of a column cell in the spatial dimension i´,j´ Divide by the sum of the response values ​​of all cells in the in-band region in the spatial dimension, if the first... Line number If a column cell belongs to an in-band region cell, then let Line number Distribution function of stray light in the spectral dimension of a pixel The value is 0, thus obtaining the spatial stray light distribution matrix. ; Step 3: Obtain the spectral stray light correction matrix B using equation (1). n×n ; (1) In equation (1), i,j for The response correction value is: (2) In equation (2), A is the identity matrix in the spectral dimension; The spatial stray light correction matrix is ​​obtained using equation (3). ; (3) In equation (3), for The response correction value is: (4) In equation (4), It is the identity matrix in spatial dimension.

2. The stray light correction method according to claim 1, characterized in that, The focusing system (2) and the collimating system (4) are reversible optical paths. The focusing system (2) and the collimating system (4) are either transmissive single convex lenses or lens groups, or reflective single off-axis parabolic lenses.

3. The stray light correction method according to claim 1, characterized in that, The spectral system (3) is a CT structure spectrometer that uses a planar grating for spectral dispersion, or a spectrometer system that uses a prism, a concave grating, or a convex grating for spectral dispersion.

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