An imaging spectrometer setup method

Abstract

This invention relates to the field of imaging spectrometer technology and discloses an imaging spectrometer assembly and adjustment method. The method includes: installing an auxiliary assembly and adjustment slit assembly at the spectrometer slit assembly mounting position; coarsely adjusting the detector using a first adjustment device to obtain a first position range that meets the first coarse adjustment conditions; successively adjusting the detector position within the first position range using the first adjustment device; after each adjustment, illuminating the auxiliary assembly and adjustment slit assembly with beams of different wavelengths using a monochromatic light source to form a slit image on the detector; determining the spectral resolution of the current detector position in the first preset field of view based on the response value of the slit image in the first preset field of view during each wavelength illumination; and determining the fixed position of the detector based on the spectral resolution of each wavelength in the first preset field of view. This invention enables quantitative optimization of spectral resolution and improves assembly and adjustment accuracy.

Description

Technical Field

[0001] This invention relates to the field of imaging spectrometer technology, and more specifically to an imaging spectrometer assembly and adjustment method. Background Technology

[0002] Imaging spectrometers offer advantages such as high spectral resolution and integrated image-spectrum mapping, making them widely used in remote sensing and scientific exploration. The setup and adjustment methods for imaging spectrometers vary due to differences in spectrometer design, equipment limitations, and the personnel involved. A common method involves using a collimator and a fringe target to simulate an infinity target. This infinity target is imaged onto a slit by an objective telescope, dispersed by the spectrometer, and then imaged onto a detector. The relative positions of the objective telescope, slit, and detector are adjusted based on the sharpness of the target's fringes output on the detector. After multiple iterations, a satisfactory position is found and fixed based on experience.

[0003] In the assembly and adjustment process of related schemes, mercury lamps, lasers, or narrowband filters are usually used to observe the sharpness of monochromatic images in certain specific bands. Based on experience, it is possible to qualitatively judge whether the detector is properly assembled and adjusted. However, it is impossible to quickly and quantitatively measure the spectral resolution during the assembly and adjustment process to achieve real-time control. Therefore, the spectral resolution cannot be quantitatively optimized, and the assembly and adjustment accuracy needs to be improved. Summary of the Invention

[0004] This invention provides a method for assembling and adjusting an imaging spectrometer to solve the technical problem of insufficient assembly and adjustment accuracy in imaging spectrometers.

[0005] In a first aspect, the present invention provides a method for assembling and adjusting an imaging spectrometer, comprising:

[0006] Install the auxiliary adjustment slit assembly at the spectrometer slit assembly mounting position;

[0007] The detector is coarsely adjusted by the first adjustment device to obtain a first position range that meets the first coarse adjustment condition.

[0008] The position of the detector is adjusted sequentially within the first position range by the first adjustment device. After each adjustment of the detector position, a monochromatic light source is used to illuminate the slit assembly with beams of different wavelengths to assist in the adjustment of the slit assembly, thereby forming a slit image on the detector.

[0009] During illumination in each band, the spectral resolution of the current detector position in the first preset field of view is determined based on the response value of the slit image in the first preset field of view of the detector.

[0010] The fixed position of the detector is determined based on the spectral resolution of each band in the first preset field of view.

[0011] In one optional implementation, during illumination at each spectral band, the spectral resolution of the current detector position in the first preset field of view is determined based on the response value of the slit image in the first preset field of view of the detector, including:

[0012] Within the current band's adjustment range, the output wavelength of the monochromatic light source is sequentially increased, and the response value of the slit image of the detector's first preset field of view in the current band is read.

[0013] Once the response value of the slit image reaches its maximum value, the first maximum value is recorded. The output wavelength of the monochromatic light source is adjusted, and the first and second output wavelengths of the monochromatic light source are recorded when the response value of the slit image reaches the first preset response value during the decrease and increase of the output wavelength, respectively. The first preset response value is 0.5 times the first maximum value.

[0014] Subtracting the first output wavelength from the second output wavelength yields the spectral resolution of the first preset field of view at the current detector position.

[0015] In one alternative implementation, the first preset field of view includes a central field of view and two peripheral fields of view.

[0016] In one optional implementation, determining the fixed position of the detector based on the spectral resolution of each band in a first preset field of view includes:

[0017] Determine whether the error between the spectral resolution of each band acquired by the detector at each position and the first target value is less than the first judgment threshold.

[0018] The average spectral resolution of each band in each field of view at each position of the detector where the error is less than the first judgment threshold is calculated, and the position of the detector with the minimum average resolution is taken as the fixed position of the detector.

[0019] In one optional implementation, the detector is coarsely adjusted using a first adjustment device to obtain a first position range that satisfies the first coarse adjustment condition, including:

[0020] Using a polychromatic light source to illuminate and assist in the adjustment of the slit assembly, alternating bright and dark striped images covering each preset band are formed in the central field of view and the two edge fields of view of the detector.

[0021] The position of the detector is adjusted sequentially by the first adjustment device, and the modulation transfer function of the fringe image of the central field of view and the two edge fields of view in each preset band is calculated after each adjustment. The first position range is obtained so that the modulation transfer function of the fringe image of the central field of view and the two edge fields of view in each preset band satisfies the first coarse adjustment condition.

[0022] In one alternative implementation, after determining the fixed position of the detector based on the spectral resolution of each band in a first preset field of view, the process includes:

[0023] Replace the auxiliary assembly slit assembly with the spectrometer slit assembly;

[0024] The objective telescope is coarsely adjusted using the second adjustment device to obtain a second position range that meets the second coarse adjustment condition.

[0025] The position of the objective telescope is adjusted sequentially within the second position range by the second adjustment device. After each adjustment of the objective telescope position, a monochromatic light source is used to illuminate the incident light tube with beams of different wavelengths through the star-shaped target, forming a star image on the detector.

[0026] During illumination in each band, the spectral resolution of the current objective telescope position in the second preset field of view is determined based on the response value of the star image in the second preset field of view of the objective telescope.

[0027] The fixed position of the objective telescope is determined based on the spectral resolution of each band in the second preset field of view.

[0028] In one optional implementation, during illumination at each spectral band, the spectral resolution of the current objective telescope position in the second preset field of view is determined based on the response value of the star image in the second preset field of view of the objective telescope, including:

[0029] Within the current band's adjustment range, the output wavelength of the monochromatic light source is sequentially increased, and the response value of the star image in the detector's second preset field of view in the current band is read.

[0030] When the response value of the star image reaches the maximum value, the second maximum value is recorded. The output wavelength of the monochromatic light source is adjusted, and the third and fourth output wavelengths of the monochromatic light source are recorded when the response value of the star image reaches the second preset response value during the decrease and increase of the output wavelength, respectively. The second preset response value is 0.5 times the second maximum value.

[0031] Subtracting the third output wavelength from the fourth output wavelength yields the spectral resolution of the second preset field of view at the current object telescope position.

[0032] In one alternative implementation, the second preset field of view includes a -1 full field of view, a central field of view, and a +1 full field of view.

[0033] In one optional implementation, determining the fixed position of the objective telescope based on the spectral resolution of each band in a second preset field of view includes:

[0034] Determine whether the error between the spectral resolution of each band acquired by the telescope at each position and the second target value is less than the second judgment threshold.

[0035] The average spectral resolution of each band in each field of view at each position of the objective telescope with an error less than the second judgment threshold is calculated, and the position of the objective telescope with the minimum average resolution is taken as the fixed position of the objective telescope.

[0036] In one optional implementation, the objective telescope is coarsely adjusted using a second adjustment device to obtain a second position range that satisfies a second coarse adjustment condition, including:

[0037] Using a polychromatic light source to illuminate the incident light tube through a striped target, a striped image of alternating light and dark bands covering each preset wavelength band is formed in the corresponding field of view of the detector.

[0038] The position of the object telescope is adjusted sequentially by the second adjustment device. After each adjustment, the imaging spectrometer is rotated by the turntable so that the fringe image passes through the -1 full field of view, the central field of view, and the +1 full field of view in sequence. The modulation transfer function of the fringe image in each preset band of the -1 full field of view, the central field of view, and the +1 full field of view is calculated. The second position range is obtained so that the modulation transfer function of the fringe image in each preset band of the -1 full field of view, the central field of view, and the +1 full field of view satisfies the second coarse adjustment condition.

[0039] The present invention has the following beneficial effects:

[0040] The imaging spectrometer assembly and adjustment method of the present invention involves installing an auxiliary assembly and adjustment slit assembly at the spectrometer slit assembly mounting position, coarsely adjusting the detector using a first adjustment device to obtain a first position range that meets the first coarse adjustment conditions, and then successively adjusting the detector position within the first position range using the first adjustment device. After each adjustment, a monochromatic light source is used to illuminate the auxiliary assembly and adjustment slit assembly with beams of different wavelengths to form a slit image on the detector. During each wavelength illumination, the spectral resolution of the current detector position in the first preset field of view is determined based on the response value of the slit image in the first preset field of view. The fixed position of the detector is determined based on the spectral resolution of each wavelength in the first preset field of view. The spectral resolution of the corresponding wavelength is calculated using the monochromatic light source and the change in the response value of the corresponding wavelength. This method enables rapid measurement of the spectral resolution for multiple fields of view and wavelengths, allowing for rapid quantitative measurement of spectral resolution during the assembly and adjustment of the imaging spectrometer detector. This enables iterative optimization of the detector position based on the spectral resolution, achieving quantitative optimization of the spectral resolution and improving the assembly and adjustment accuracy. Attached Figure Description

[0041] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0042] Figure 1 This is a schematic flowchart of the imaging spectrometer assembly and adjustment method according to an embodiment of the present invention;

[0043] Figure 2 This is a schematic diagram of the optical path for assembling and adjusting the detector according to an embodiment of the present invention;

[0044] Figure 3 This is a schematic diagram of the auxiliary assembly and adjustment slit assembly according to an embodiment of the present invention;

[0045] Figure 4 This is a schematic diagram of the optical path for assembling the telescope according to an embodiment of the present invention;

[0046] Explanation of reference numerals in the attached figures:

[0047] 1. Integrating sphere; 2. Polychromatic light source; 3. Monochromatic light source; 4. Auxiliary adjustment slit assembly; 5. First adjustment device; 6. Second adjustment device; 7. Spectrometer slit assembly; 8. Objective telescope; 9. Target; 10. Incident light tube; 11. Two-dimensional turntable; 12. Spectrometer frame. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] This invention provides a method for assembling and adjusting an imaging spectrometer, which enables rapid quantitative measurement of spectral resolution during the assembly and adjustment process, thereby allowing for real-time control and achieving quantitative optimization of spectral and spatial resolution.

[0050] To enable those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0051] According to an embodiment of the present invention, an imaging spectrometer assembly and adjustment method is provided, combining... Figure 1 and Figure 2 As shown, the method includes:

[0052] Step S101: Install the auxiliary adjustment slit assembly 4 at the spectrometer slit assembly mounting position.

[0053] Specifically, such as Figure 3 As shown, the auxiliary adjustment slit assembly 4 has at least three slit channels, each slit channel including several equidistant slits, and the width of the slits and their spacing are the same. Among them, Figure 3 The black portion represents the light-transmitting part of the slit, while the white portion represents the opaque part. The auxiliary adjustment slit assembly 4 has a length of L and a width of W, and its dimensions must match the mounting surface. The total length of the slit is a, and the size of a must cover the entire field of view.

[0054] Four straight slit regions are used to test the spectral resolution at different field-of-view locations, including two middle straight slit regions and two edge straight slit regions. The lengths of the middle straight slit regions and the edge straight slit regions are b and c, respectively. The size of b must be sufficient to cover the edge field of view to be measured, while the size of c has no special requirements.

[0055] Between the four straight slit regions are three alternating bright and dark stripe regions. This region is used to test the modulation transfer function. The interval between these alternating bright and dark stripes is d, which should be consistent with the slit width. The slit width is equal to the detector pixel width.

[0056] The points spaced evenly within the slit are primarily used to measure the modulation transfer function (MTF), while the remaining area outside these points can be used to measure the spectral resolution. This auxiliary slit assembly 4 allows for simultaneous measurement of both MTF and spectral resolution, facilitating synchronized optimization without requiring replacement of the slit assembly.

[0057] In step S102, the detector is coarsely adjusted by the first adjustment device 5 to obtain a first position range that meets the first coarse adjustment conditions.

[0058] Specifically, the detector is set inside the spectrometer frame 12 of the imaging spectrometer, and the first adjustment device 5 adopts a six-dimensional adjustment platform, which can adjust the distance between the four corners of the detector and the spectrometer frame 12.

[0059] The purpose of coarse adjustment is to position the detector within the focal depth range of the spectrometer, obtaining the first position range D1-D2 that includes the four corners of the detector.

[0060] In step S103, the position of the detector is adjusted sequentially within the first position range by the first adjustment device 5. After each adjustment of the detector position, the slit assembly 4 is illuminated with beams of different wavelengths by the monochromatic light source 3 to assist in the adjustment and formation of a slit image on the detector.

[0061] Step S104: During illumination in each band, determine the spectral resolution of the current detector position in the first preset field of view based on the response value of the slit image in the first preset field of view of the detector.

[0062] Step S105: Determine the solidification position of the detector based on the spectral resolution of each band in the first preset field of view.

[0063] Specifically, steps S103 to S105 are the process of quantitatively assembling and adjusting the detector based on spectral resolution.

[0064] Monochromatic light source 3 typically employs a monochromator, which can output beams of different wavelengths, dividing them into different output bands. During setup and adjustment, the output wavelength of monochromatic light source 3 is adjusted at set intervals to achieve different output bands.

[0065] When the wavelength of the beam output by the monochromator changes, the band corresponding to the slit image on the detector also changes accordingly. For example, the monochromator has a total of 10 bands: band n1 is the starting band of the wavelength, corresponding to a center wavelength of 500 nm, and band n10 is the ending band of the wavelength, corresponding to a center wavelength of 600 nm. Therefore, when the monochromator output wavelength is 500 nm, the slit image only appears in band n1. When the monochromator output wavelength increases from 500 nm to 600 nm, the slit image will sequentially move from band n1 to band n10.

[0066] The first preset field of view includes multiple fields of view, such as a central field of view and two peripheral fields of view.

[0067] After adjusting the detector to a position, the output wavelength of the monochromatic light source 3 is adjusted so that the slit image moves to a position close to the initial wavelength of band n1. After subtracting the pre-collected dark background data, the response values ​​of each field of view of the detector are read. Based on the response values ​​of the detector in each first preset field of view, the spectral resolution of the detector at the current position in each first preset field of view is calculated.

[0068] Then, the detector is adjusted to the next position to obtain the spectral resolution of the detector in each of the first preset fields of view at the next position. This process is repeated to obtain the spectral resolution of the detector at each position within the first position range. The position with the minimum spectral resolution that meets the design expectation is selected as the final position of the detector, and the detector is then fixed.

[0069] The imaging spectrometer assembly and adjustment method of this invention involves installing an auxiliary assembly and adjustment slit assembly 4 at the slit assembly mounting position of the imaging spectrometer, coarsely adjusting the detector using a first adjustment device 5 to obtain a first position range that meets the first coarse adjustment conditions, and then successively adjusting the detector position within the first position range using the first adjustment device 5. After each adjustment, a monochromatic light source 3 illuminates the auxiliary assembly and adjustment slit assembly 4 with beams of different wavelengths to form a slit image on the detector. During each wavelength illumination, the spectral resolution of the current detector position in the first preset field of view is determined based on the response value of the slit image in the first preset field of view. The fixed position of the detector is determined based on the spectral resolution of each wavelength in the first preset field of view. The spectral resolution of the corresponding wavelength is calculated using the monochromatic light source 3 and the change in the response value of the corresponding wavelength. This method enables rapid measurement of the spectral resolution for multiple fields of view and wavelengths, allowing for rapid quantitative measurement of spectral resolution during the assembly and adjustment of the imaging spectrometer detector. This enables iterative optimization of the detector position based on the spectral resolution, achieving quantitative optimization of the spectral resolution and improving the assembly and adjustment accuracy.

[0070] In some embodiments, step S102, coarsely adjusting the detector using the first adjustment device 5 to obtain a first position range that satisfies the first coarse adjustment condition, includes:

[0071] Step S1021: Use the polychromatic light source 2 to illuminate and assist the adjustment of the slit assembly 4 to form alternating bright and dark striped images covering each preset band at the center field of view and the two edge field of view positions of the detector.

[0072] Step S1022: The position of the detector is adjusted sequentially by the first adjustment device 5, and the modulation transfer function of the fringe image of the center field of view and the two edge fields of view in each preset band is calculated after each adjustment of the detector position, so as to obtain the first position range that makes the modulation transfer function of the fringe image of the center field of view and the two edge fields of view in each preset band satisfy the first coarse adjustment condition.

[0073] Specifically, the integrating sphere 1, together with the polychromatic light source 2, is used to illuminate the auxiliary adjustment slit assembly 4, making the beam more uniform.

[0074] The auxiliary adjustment slit assembly 4 has three slit channels. After being illuminated by the polychromatic light source 2 and the integrating sphere 1, three sets of alternating bright and dark stripe images covering each band are formed at the corresponding field of view of the detector. These three sets of stripe images reflect the spatial resolution of the central field of view and the two peripheral fields of view, respectively.

[0075] After subtracting the pre-acquired dark background data, the detector data reading system reads the brightness response value of each fringe in the three sets of fringe images. and dark pixel value Using the formula:

[0076]

[0077] After calculating the modulation transfer function (MTF) of each fringe pair, the average value is taken to obtain the MTF of each band fringe image in the central field of view and the two edge fields of view.

[0078] The detector is adjusted to the next position by the first adjustment device 5. The previous steps are repeated to obtain the MTF of each band of the three fields of view at the current position. The positions of the four corners of the detector are adjusted in turn, and the distances d1, d2, d3 and d4 of each corner from the spectrometer frame 12 are recorded, as well as the MTF values ​​of each band of the three fields of view.

[0079] When the MTF of the left field of view decreases, the distance between d1 and d2 on the left is adjusted in the opposite direction to increase the MTF. Similarly, when the MTF of the right field of view decreases, the distance between d3 and d4 on the right is adjusted to increase the MTF. The central field of view requires simultaneous adjustment of d1, d2, d3 and d4. This process is iterated one by one until the position range D1 to D2 of the three fields of view where the MTF of each band satisfies the first coarse adjustment condition is obtained. This position range is within the focal depth range of the spectrometer.

[0080] The first coarse adjustment condition is to determine the position range of the four corners where the MTF of each band in the three fields of view is basically consistent and remains basically unchanged. Specifically, the first coarse adjustment condition is that the error between the MTF of each band and the set MTF value is less than a preset proportion. For example, when the error between the MTF of each band and the set MTF value is less than 5%, the first coarse adjustment condition is considered to be met.

[0081] The above scheme utilizes the modulation transfer function of the polychromatic light source 2 and the fringe image for coarse adjustment, which can quickly determine the approximate suitable position range of the detector, providing a good foundation for subsequent precise adjustment, improving assembly and adjustment efficiency, and reducing assembly and adjustment time.

[0082] In some embodiments, step S104, determining the spectral resolution of the current detector position in the first preset field of view based on the response value of the slit image in the first preset field of view of the detector during illumination in each band, includes:

[0083] Step S1041: Within the adjustment range of the current band, sequentially increase the output wavelength of the monochromatic light source 3, and read the response value of the slit image of the detector's first preset field of view in the current band.

[0084] Step S1042: After the response value of the slit image reaches the maximum value, the first maximum value is recorded. The output wavelength of the monochromatic light source 3 is adjusted, and the first output wavelength and the second output wavelength of the monochromatic light source 3 are recorded when the response value of the slit image reaches the first preset response value during the decrease and increase of the output wavelength, respectively. The first preset response value is 0.5 times the first maximum value.

[0085] Step S1043: Subtract the first output wavelength from the second output wavelength to obtain the spectral resolution of the first preset field of view at the current detector position.

[0086] Specifically, the first preset field of view includes a central field of view and two peripheral fields of view.

[0087] Adjust the output wavelength of monochromatic light source 3 to a position close to the initial wavelength of the current band. Adjust the output wavelength of monochromatic light source 3 at a set interval, such as 0.1 nm interval, and read the response value R of the current band of the edge field of view in real time. When the response value R reaches the first maximum value M1, adjust the output wavelength of monochromatic light source 3 in the direction of decreasing wavelength until the response value reaches the set value. The set value is generally 0.5M1. For example, take the set value as 0.5M1. That is, when the response value reaches 0.5M1, record the output wavelength of monochromatic light source 3 at this time as the first output wavelength a1. Adjust the output wavelength of monochromatic light source 3 in the direction of increasing wavelength. When the response value of the current band reaches 0.5M1 again, record the output wavelength of monochromatic light source 3 at this time as the second output wavelength a2. Then the spectral resolution of the edge field of view of the current band is a2-a1.

[0088] Using the same steps, obtain the spectral resolution of another edge market and center field of view.

[0089] By sequentially adjusting the wavelength of the monochromatic light source 3, the slit image is moved to the next band, and the spectral resolution of the three fields of view in the next band can be measured, thereby obtaining the spectral resolution of each field of view in each band.

[0090] In one example, the preset bands include a starting band n1, a middle band n2, and an ending band n3. Therefore, there are nine spectral resolutions corresponding to each field of view in each band. These nine spectral resolutions can be used as an evaluation basis for the overall spectral resolution of the imaging spectrometer. The first adjustment device 5 is adjusted so that the detector moves within the position range D1 to D2 of the four corners determined during coarse adjustment. Steps S1041 to S1043 are repeated to obtain the nine spectral resolutions corresponding to each position.

[0091] It should be understood that the number of preset bands can be set as needed. The more preset bands there are, the more accurate the measurement results will be, but the longer the measurement time will be. For example, the spectral response data of the bands can be obtained by scanning point by point with a monochromatic light source at a step size of 1 / 50 of the spectral resolution using 3 wavelengths. The spectral response function can then be fitted using this data, and the spectral resolution can be calculated from the spectral response function. This method takes longer, but the measurement accuracy is relatively higher.

[0092] By precisely controlling the output wavelength of the monochromatic light source 3 and recording the wavelength corresponding to a specific response value, the spectral resolution can be accurately calculated, providing reliable data for determining the optimal curing position of the detector and improving the accuracy and reliability of the assembly.

[0093] Further, step S105, determining the fixed position of the detector based on the spectral resolution of each band in the first preset field of view, includes:

[0094] Step S1051: Determine whether the error between the spectral resolution of each band acquired by the detector at each position and the first target value is less than the first judgment threshold.

[0095] Step S1052: Calculate the average spectral resolution of each band in each field of view at each position of the detector where the error is less than the first judgment threshold, and take the position of the detector when the average resolution is the smallest as the fixed position of the detector.

[0096] Specifically, the first target value can be set according to the actual situation, such as the standard resolution of the imaging spectrometer or the average value of the spectral resolution of each band in each field of view.

[0097] The first judgment threshold can be set according to actual needs, such as 3%, 5%, 7%, etc.

[0098] By comparing the error between each spectral resolution and the target value to see if it is less than the first judgment threshold, it is determined whether each spectral resolution is basically consistent, so that the current position meets the design expectations.

[0099] Under the premise that the spectral resolutions are basically consistent, the average resolution of each band at each position in each field of view is calculated. The position with the smallest average resolution is taken as the final fixed position of the detector. This can obtain the detector position with the smallest resolution and the detection results of each field of view. It can achieve the optimal balance of spectral resolution and spatial resolution, avoid the subjectivity of human visual judgment, and improve the accuracy of assembly and adjustment.

[0100] In some embodiments, step S105, after determining the fixed position of the detector based on the spectral resolution of each band in the first preset field of view, includes:

[0101] Step S106: Replace the auxiliary adjustment slit assembly 4 with the spectrometer slit assembly 7.

[0102] Specifically, in combination Figure 4 As shown, the spectrometer slit assembly 7 is the original slit assembly of the imaging spectrometer. In subsequent steps, the objective telescope 8 needs to be positioned, so the auxiliary adjustment slit assembly 4 needs to be replaced with the spectrometer slit assembly 7.

[0103] In step S107, the objective telescope 8 is coarsely adjusted using the second adjustment device 6 to obtain a second position range that meets the second coarse adjustment conditions.

[0104] The objective telescope 8 is positioned at the front end of the spectrometer frame 12 of the imaging spectrometer. The second adjustment device 6 is a six-dimensional adjustment platform, which can adjust the distance between the four corners of the objective telescope 8 and the spectrometer frame 12.

[0105] The purpose of coarse adjustment is to position the object telescope 8 within the focal depth range of the spectrometer, thereby obtaining the second position range D3-D4, which includes the four corners of the object telescope 8.

[0106] In step S108, the position of the object telescope 8 is adjusted sequentially within the second position range by the second adjustment device 6. After each adjustment of the position of the object telescope 8, the incident light tube 10 is illuminated by a monochromatic light source 3 with beams of different wavelengths through the star-shaped target 9, forming a star image on the detector.

[0107] Step S109: During illumination in each band, determine the spectral resolution of the current position of the object telescope 8 in the second preset field of view based on the response value of the star image in the second preset field of view of the object telescope 8.

[0108] Step S1010: Determine the solidification position of the object telescope 8 based on the spectral resolution of each band in the second preset field of view.

[0109] Specifically, steps S108 to S1010 are the process of assembling the telescope 8 based on spectral resolution quantitative adjustment.

[0110] Monochromatic light source 3 typically employs a monochromator, which can output beams of different wavelengths, dividing them into different output bands. During setup and adjustment, the output wavelength of monochromatic light source 3 is adjusted at set intervals to achieve different output bands.

[0111] The beam output from the monochromatic light source 3 passes through the star-shaped target 9, and after being adjusted by the incident light tube 10, it is incident parallel to the objective telescope 8, forming a star image on the detector. The incident light tube 10 is a collimator.

[0112] The second preset field of view includes multiple fields of view, such as the -1 full field of view, the central field of view, and the +1 full field of view. By adjusting the two-dimensional turntable 11, the spectrometer frame 12 is rotated on the horizontal plane so that the star image passes through the -1 full field of view, the central field of view, and the +1 full field of view in sequence.

[0113] After adjusting the objective telescope 8 to a position, the output wavelength of the monochromatic light source 3 is adjusted so that the star image moves to a position close to the initial wavelength of band n1. After subtracting the pre-collected dark background data, the response values ​​of each field of view of the detector are read. Based on the response values ​​of the detector in each second preset field of view, the spectral resolution of the detector at the current position in each second preset field of view is calculated.

[0114] Then, the object telescope 8 is adjusted to the next position to obtain the spectral resolution of the detector at each of the second preset fields of view. This process is repeated to obtain the spectral resolution of the object telescope 8 at each position within the second position range. The position with the minimum spectral resolution that meets the design expectation is selected as the final position of the object telescope 8, and the object telescope 8 is solidified.

[0115] After the detector is assembled and adjusted, the objective telescope 8 is assembled and adjusted in a similar manner. By using the star-shaped target 9 and the monochromatic light source 3 for illumination, the influence of the position of the objective telescope 8 on the spectral resolution can be accurately evaluated, its optimal fixed position can be determined, and the overall performance of the imaging spectrometer can be further improved, ensuring that the objective lens system and the detector system work together to achieve the best results.

[0116] In some embodiments, step S107, coarsely adjusting the objective telescope 8 using the second adjustment device 6 to obtain a second position range that satisfies the second coarse adjustment condition, includes:

[0117] Step S1071: Using the polychromatic light source 2, the incident light tube 10 is illuminated through the striped target 9 to form a striped image of alternating light and dark bands covering each preset wavelength in the corresponding field of view of the detector.

[0118] In step S1072, the position of the object telescope 8 is adjusted sequentially by the second adjustment device 6. After each adjustment of the position of the object telescope 8, the imaging spectrometer is rotated by the turntable so that the fringe image passes through the -1 full field of view, the central field of view, and the +1 full field of view in sequence. The modulation transfer function of the fringe image in each preset band of the -1 full field of view, the central field of view, and the +1 full field of view is calculated. The second position range is obtained so that the modulation transfer function of the fringe image in each preset band of the -1 full field of view, the central field of view, and the +1 full field of view satisfies the second coarse adjustment condition.

[0119] Specifically, the second preset field of view includes a -1 full field of view, a central field of view, and a +1 full field of view.

[0120] The striped target 9 is illuminated using an integrating sphere 1 and a polychromatic light source 2. The light beam then enters the objective telescope 8 and the detector through an incident light tube 10. The objective telescope 8, mounted on it, is adjusted by a second adjustment device 6 to form a set of alternating bright and dark striped images covering various wavelengths at the corresponding field of view of the detector. The spectrometer frame 12 is adjusted by a two-dimensional turntable 11 so that the striped images pass sequentially through the -1 full field of view, the central field of view, and the +1 full field of view.

[0121] After subtracting the pre-acquired dark background data, the detector data reading system reads the brightness response value of each fringe at three field-of-view locations. and dark pixel value Using the formula:

[0122]

[0123] After calculating the modulation transfer function (MTF) of each fringe pair, the average value is taken to obtain the MTF of the fringe images in each band for the three second preset fields of view: -1 full field of view, center field of view, and +1 full field of view.

[0124] Adjust the object telescope 8 to the next position using the second adjustment device 6, repeat the previous steps to obtain the MTF of each band in the three fields of view at the current position, adjust the positions of the four corners of the detector in turn, record the distance of each of the four corners from the spectrometer frame 12, and the MTF value of each band in the three fields of view.

[0125] When the MTF of the left field of view decreases, the distance on the left is adjusted in the opposite direction to increase the MTF. Similarly, when the MTF of the right field of view decreases, the distance on the right is adjusted to increase the MTF. The distances of the four corners and the spectrometer frame 12 of the central field of view need to be adjusted simultaneously. Through iterative steps, the position range D3 to D4 of the three fields of view where the MTF of each band satisfies the second coarse adjustment condition is finally obtained. This position range is within the focal depth range of the spectrometer.

[0126] The second coarse adjustment condition is to determine the position range of the four corners where the MTF of each band in the three fields of view is basically consistent and remains basically unchanged. Specifically, the second coarse adjustment condition is that the error between the MTF of each band and the set MTF value is less than a preset proportion. For example, when the error between the MTF of each band and the set MTF value is less than 5%, the second coarse adjustment condition is considered to be met.

[0127] The above scheme utilizes the modulation transfer function of the polychromatic light source 2 and the striped target 9 for coarse adjustment, which can quickly determine the approximate suitable position range of the objective telescope 8, providing a good foundation for subsequent precise adjustment, improving assembly and adjustment efficiency, and reducing assembly and adjustment time.

[0128] In some embodiments, step S109, determining the spectral resolution of the current position of the object telescope 8 in the second preset field of view based on the response value of the star image in the second preset field of view of the object telescope 8 during illumination in each band, includes:

[0129] Step S1091: Within the adjustment range of the current band, sequentially increase the output wavelength of the monochromatic light source 3, and read the response value of the star image of the second preset field of view of the detector in the current band.

[0130] Step S1092: After the response value of the star image reaches the maximum value, the second maximum value is recorded. The output wavelength of the monochromatic light source 3 is adjusted, and the third and fourth output wavelengths of the monochromatic light source 3 are recorded when the response value of the star image reaches the second preset response value during the decrease and increase of the output wavelength, respectively. The second preset response value is 0.5 times the second maximum value.

[0131] Step S1093: Subtract the third output wavelength from the fourth output wavelength to obtain the spectral resolution of the second preset field of view at the current position of the object telescope 8.

[0132] Specifically, the second preset field of view includes a -1 full field of view, a central field of view, and a +1 full field of view.

[0133] Adjust the output wavelength of monochromatic light source 3 to a position close to the initial wavelength of the current band. Adjust the output wavelength of monochromatic light source 3 at a set interval, such as 0.1 nm interval, and read the response value R of the current band of the -1 full field of view in real time. When the response value R reaches the second maximum value M2, adjust the output wavelength of monochromatic light source 3 in the direction of decreasing wavelength until the response value reaches the set value. This set value is generally 0.2M2 to 0.8M2. For example, take the set value as 0.5M2. That is, when the response value reaches 0.5M2, record the output wavelength of monochromatic light source 3 at this time as the third output wavelength a3. Adjust the output wavelength of monochromatic light source 3 in the direction of increasing wavelength. When the response value of the current band reaches 0.5M2 again, record the output wavelength of monochromatic light source 3 at this time as the fourth output wavelength a4. Then the spectral resolution of the current band -1 full field of view is a4-a3.

[0134] The same steps were used to obtain the spectral resolution of the center field of view and the +1 full field of view.

[0135] By sequentially adjusting the wavelength of the monochromatic light source 3, the star image is moved to the next band, and the spectral resolution of the three fields of view in the next band can be measured, thereby obtaining the spectral resolution of each field of view in each band.

[0136] In one example, the preset bands include a starting band n1, a middle band n2, and an ending band n3. Therefore, there are nine spectral resolutions corresponding to each field of view in each band. These nine spectral resolutions can be used as an evaluation criterion for the overall spectral resolution of the imaging spectrometer. The second adjustment device 6 is adjusted so that the objective telescope 8 moves within the position range D3 to D4 of the four corners determined during coarse adjustment. Steps S1091 to S1093 are repeated to obtain the nine spectral resolutions corresponding to each position.

[0137] It should be understood that the number of preset bands can be set as needed. The more preset bands there are, the more accurate the measurement results will be, but the longer it will take.

[0138] By precisely controlling the output wavelength of the monochromatic light source 3 and recording the wavelength corresponding to a specific response value, the spectral resolution can be accurately calculated, providing reliable data for determining the optimal curing position of the objective telescope 8 and improving the accuracy and reliability of the assembly.

[0139] In some embodiments, step S1010, determining the solidification position of the object telescope 8 based on the spectral resolution of each band in the second preset field of view, includes:

[0140] Step a1: Determine whether the error between the spectral resolution of each band acquired by the object telescope 8 at each position and the second target value is less than the second judgment threshold.

[0141] Step a2: Calculate the average spectral resolution of each band in each field of view at each position of the object telescope 8 where the error is less than the second judgment threshold, and take the position of the object telescope 8 when the average resolution is the smallest as the fixed position of the object telescope 8.

[0142] Specifically, the second target value can be set according to the actual situation, such as the standard resolution of the imaging spectrometer or the average value of the spectral resolution of each band in each field of view.

[0143] The second judgment threshold can be set according to actual needs, such as 3%, 5%, 7%, etc.

[0144] By comparing the error between each spectral resolution and the second target value to see if it is less than the second judgment threshold, it is determined whether each spectral resolution is basically consistent, so that the current position meets the design expectations.

[0145] Under the premise that the spectral resolutions are basically the same, the average resolution of each band at each position in each field of view is calculated. The position with the smallest average resolution is taken as the final fixed position of the objective telescope 8. This can obtain the position of the objective telescope 8 with the smallest resolution and the detection results of each field of view. It can achieve the optimal balance of spectral resolution and spatial resolution, avoid the subjectivity of human visual judgment, and improve the accuracy of assembly and adjustment.

[0146] In summary, this embodiment of the invention uses the monochromatic light source 3 and the change in the corresponding band response value to calculate the spectral resolution of the band, enabling rapid measurement of the spectral resolution of multiple fields of view and bands. Based on the measured values, the positions of the detector and the objective telescope 8 are iteratively optimized, achieving quantitative and rapid measurement results to adjust the positions of the detector and the objective telescope 8 in real time. This achieves balanced optimization of spectral and spatial resolution, avoids the subjectivity of human visual judgment, and improves the accuracy of assembly and adjustment.

[0147] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A method for assembling and adjusting an imaging spectrometer, characterized in that, include: Install the auxiliary adjustment slit assembly at the spectrometer slit assembly mounting position; The detector is coarsely adjusted by the first adjustment device to obtain a first position range that meets the first coarse adjustment condition. The position of the detector is adjusted sequentially within the first position range by the first adjustment device. After each adjustment of the detector position, the auxiliary adjustment slit assembly is illuminated with beams of different wavelengths using a monochromatic light source to form a slit image on the detector. During illumination in each band, the spectral resolution of the current detector position in the first preset field of view is determined based on the response value of the slit image in the first preset field of view of the detector. The solidification position of the detector is determined based on the spectral resolution of each band in the first preset field of view; Specifically, during illumination at each spectral band, the spectral resolution of the current detector position within the first preset field of view is determined based on the response value of the slit image in the detector's first preset field of view, including: Within the current band's adjustment range, the output wavelength of the monochromatic light source is sequentially increased, and the response value of the slit image of the detector's first preset field of view in the current band is read. When the response value of the slit image reaches the maximum value, the first maximum value is recorded. The output wavelength of the monochromatic light source is adjusted, and the first output wavelength and the second output wavelength of the monochromatic light source are recorded when the response value of the slit image reaches the first preset response value during the decrease and increase of the output wavelength, respectively. The first preset response value is 0.5 times the first maximum value. Subtracting the first output wavelength from the second output wavelength yields the spectral resolution of the first preset field of view at the current detector position; The first preset field of view includes a central field of view and two peripheral fields of view; The detector is coarsely adjusted using a first adjustment device to obtain a first position range that satisfies the first coarse adjustment condition, including: The auxiliary adjustment slit assembly is illuminated using a polychromatic light source to form alternating bright and dark striped images covering each preset band at the detector's central field of view and two edge field of view positions. The position of the detector is adjusted sequentially by the first adjustment device, and the modulation transfer function of the fringe image of the central field of view and the two edge fields of view in each preset band is calculated after each adjustment. The first position range is obtained so that the modulation transfer function of the fringe image of the central field of view and the two edge fields of view in each preset band satisfies the first coarse adjustment condition.

2. The imaging spectrometer assembly and adjustment method according to claim 1, characterized in that, The fixed position of the detector is determined based on the spectral resolution of each band in the first preset field of view, including: Determine whether the error between the spectral resolution of each band acquired by the detector at each position and the first target value is less than the first judgment threshold. The average spectral resolution of each band in each field of view at each position of the detector where the error is less than the first judgment threshold is calculated, and the position of the detector with the minimum average resolution is taken as the fixed position of the detector.

3. The imaging spectrometer assembly and adjustment method according to claim 1, characterized in that, After determining the fixed position of the detector based on the spectral resolution of each band in the first preset field of view, the process includes: Replace the auxiliary assembly slit assembly with a spectrometer slit assembly; The objective telescope is coarsely adjusted using the second adjustment device to obtain a second position range that meets the second coarse adjustment condition. The position of the objective telescope is adjusted sequentially within the second position range by the second adjustment device. After each adjustment of the objective telescope position, a monochromatic light source is used to illuminate the incident light tube with beams of different wavelengths through the star-shaped target, forming a star image on the detector. During illumination in each band, the spectral resolution of the current objective telescope position in the second preset field of view is determined based on the response value of the star image in the second preset field of view of the objective telescope. The fixed position of the object telescope is determined based on the spectral resolution of each band in the second preset field of view.

4. The imaging spectrometer assembly and adjustment method according to claim 3, characterized in that, During illumination at each wavelength, the spectral resolution of the current objective telescope position within the second preset field of view is determined based on the response value of the star image in the objective telescope's second preset field of view, including: Within the adjustment range of the current band, the output wavelength of the monochromatic light source is increased sequentially, and the response value of the star image of the second preset field of view of the detector in the current band is read. When the response value of the star image reaches the maximum value, the second maximum value is recorded. The output wavelength of the monochromatic light source is adjusted, and the third and fourth output wavelengths of the monochromatic light source are recorded when the response value of the star image reaches the second preset response value during the decrease and increase of the output wavelength, respectively. The second preset response value is 0.5 times the second maximum value. Subtracting the third output wavelength from the fourth output wavelength yields the spectral resolution of the second preset field of view at the current object telescope position.

5. The imaging spectrometer assembly and adjustment method according to claim 3 or 4, characterized in that, The second preset field of view includes a -1 full field of view, a center field of view, and a +1 full field of view.

6. The imaging spectrometer assembly and adjustment method according to claim 5, characterized in that, The fixed position of the objective telescope is determined based on the spectral resolution of each band in the second preset field of view, including: Determine whether the error between the spectral resolution of each band acquired by the telescope at each position and the second target value is less than the second judgment threshold. The average spectral resolution of each band in each field of view at each position of the objective telescope with an error less than the second judgment threshold is calculated, and the position of the objective telescope with the minimum average resolution is taken as the fixed position of the objective telescope.

7. The imaging spectrometer assembly and adjustment method according to claim 6, characterized in that, The objective telescope is coarsely adjusted using the second adjustment device to obtain a second position range that satisfies the second coarse adjustment condition, including: Using a polychromatic light source to illuminate the incident light tube through a striped target, a striped image of alternating light and dark bands covering each preset wavelength band is formed in the corresponding field of view of the detector. The position of the object telescope is adjusted sequentially by the second adjustment device. After each adjustment, the imaging spectrometer is rotated by the turntable so that the fringe image passes through the -1 full field of view, the central field of view, and the +1 full field of view in sequence. The modulation transfer function of the fringe image in each preset band of the -1 full field of view, the central field of view, and the +1 full field of view is calculated. The second position range is obtained so that the modulation transfer function of the fringe image in each preset band of the -1 full field of view, the central field of view, and the +1 full field of view satisfies the second coarse adjustment condition.

Images