Spectral imaging system based on annular gradient filter

Abstract

The present application relates to a kind of spectral imaging systems based on annular gradient filter, including zoom modulation module, light splitting module, collection imaging module and image processing module.The system uses annular gradient filter as light splitting element, combines drive control module as the light splitting module for spectral imaging, while, annular gradient filter is arranged at the focal plane of zoom modulation module, avoid the size of imaging module to the size of annular gradient filter Limit, improve the light splitting precision.The system completes the wavelength matching reconstruction of image by area matching and edge interpolation, and generates three-dimensional spectral image quickly.The present application can be applicable to visible light, infrared band under the spectral gaze imaging based on annular gradient filter, with compact, stable, high precision, low cost and other advantages.

Description

Technical Field

[0001] This invention relates to a spectral imaging system based on a ring-shaped gradient filter, belonging to the field of spectral imaging technology. Background Technology

[0002] Compared to traditional two-dimensional imaging techniques, spectral imaging adds a third dimension of wavelength spectral information. Different substances and structures produce different characteristic peaks in different wavelength bands, greatly facilitating the understanding and research of the composition, structure, and properties of matter. Therefore, spectral imaging is currently widely used in geological exploration, agriculture and environmental monitoring, remote sensing and earth surveying, medical detection, and biological science research. Commonly used spectral imaging methods include: The first is dispersive spectral imaging: using dispersive elements (such as gratings or prisms) to disperse light of different wavelengths, which are then captured by a camera or detector, obtaining one-dimensional spatial and spectral information on the image plane. A three-dimensional data cube can generally be obtained through pushbroom techniques. The second is filter-based spectral imaging: by placing specific filters or bandpass filter arrays in front of a conventional imaging system, light within a specific wavelength range is selected for imaging.

[0003] Common dispersive spectral imaging methods include beam splitters, direct field scanning, and pushbroom techniques. To achieve high-quality imaging, these three methods generally require high-precision, high-stability displacement platforms and complex optical path systems, resulting in high costs and limited application. Furthermore, since dispersive spectral imaging often employs line scanning, the two-dimensional imaging time is relatively long.

[0004] Commonly used filter-based spectral imaging employs rectangular bandpass filter arrays. This method is staring imaging, eliminating the need for spatial sweeping. However, it requires real-time adjustment of the filter array position during spectral sampling, or alteration of the beam position using refracting prisms to achieve filtering across different bands. The spectral resolution of filter-based imaging depends on the number of filters, i.e., the number of spectral channels. Compared to the dispersive methods described above, this method can rapidly acquire multiple single-band spectral images, but its spectral resolution is generally lower than that of dispersive methods. Furthermore, achieving fast and accurate spectral channel switching often requires high-precision displacement stages or refracting lenses, resulting in higher system complexity and cost. Summary of the Invention

[0005] The purpose of this application is to provide an improved spectral imaging system. Ideally, it can achieve compact, stable, high-precision, and low-cost spectral imaging in any wavelength band, such as the visible light band and the infrared band.

[0006] To achieve the above objectives, embodiments of the present invention provide a spectral imaging system based on an annular graded filter. The annular graded filter includes multiple filtering regions with different transmission center wavelengths in transmission bands, and provides a set of graduated markings along the radial direction. The system includes a zoom modulation module composed of a first converging lens group disposed on the front side of the annular graded filter and a second converging lens group disposed on the rear side of the annular graded filter; the first converging lens group... The lens group is configured such that a first image focal plane on the annular graduated filter forms a first image of an object located in front of the first converging lens group; the annular graduated filter is configured to rotate at least one revolution to complete one sampling cycle during the acquisition of spectral data, ensuring that each filter region can rotate sequentially and overlap with the first image focal plane region; an imaging module consisting of a camera and an imaging lens group is disposed behind the second converging lens group; wherein the operating wavelengths of the imaging lens group and the camera are matched with the wavelength of the annular graduated filter. The imaging system is configured to acquire multiple image frames at multiple sampling time points within a sampling period and generate a raw spectral dataset of the multiple image frames. It also includes an image processing module configured to perform the following processing steps: collecting and saving the raw spectral dataset; establishing a position-time equation for each filter region based on the raw spectral dataset, including obtaining the rotational speed of the annular gradient filter, using the filter region where the marked pattern is located as a reference filter region, and establishing the position-time equation for the reference filter region; then obtaining the position-time equations for other filter regions based on the angle difference between other filter regions and the reference filter region, and after angle compensation; calibrating the position of the first image in the focal plane of the first image based on the marked pattern; matching the position of each pixel in each image frame with the position-time equations of each filter region corresponding to the acquisition time point of the image frame; and rearranging the spectral amplitude matrix of each pixel in the raw spectral dataset based on wavelength according to the matching result to obtain a wavelength amplitude matrix, and completing spectral image reconstruction based on the wavelength amplitude matrix.

[0007] Preferably, in some embodiments, interpolation processing is also included for the pixels at the edge of the filter area.

[0008] Preferably, in some embodiments, the marked graphic is a graphic used to mark measurements, such as a ruler or dots.

[0009] Preferably, in some embodiments, the rotational speed of the annular gradient filter is obtained directly by a motor controller or by image calculation.

[0010] Preferably, in some embodiments, the first converging lens group, the second converging lens group, and the imaging lens group are each composed of one or more lenses to achieve clear, high-quality imaging.

[0011] Preferably, in some embodiments, the annular gradient filter is driven by a micro rotary motor, which is controlled by a motor controller.

[0012] Preferably, in some embodiments, the annular gradient filter is a circular annular gradient filter, the filtering area is a fan-shaped filtering area, the annular gradient filter can also be a gradient filter with polygonal annular distribution, and the filtering area is a trapezoidal or rectangular filtering area.

[0013] Preferably, in some embodiments, the spectral resolution of the filter region depends on the central angle corresponding to its annular distribution, and the central angle of the annular distribution corresponding to a single filter region is no greater than 18°, preferably 16°, 3.6° or smaller to achieve hyperspectral imaging.

[0014] Preferably, in some embodiments, the spectral resolution of the filter region depends on the central angle corresponding to its annular distribution, and the central angle of the annular distribution corresponding to a single filter region is greater than 18°, preferably 20°, 50° or larger, to achieve multispectral imaging.

[0015] Preferably, in some embodiments, the transmission band is the same within a filter area, and the transmission band changes continuously along the rotation direction in all filter areas on the gradient filter.

[0016] This invention presents a spectral imaging system based on a ring-shaped graded filter. It achieves spectral imaging through an independent beam splitting module and a wavelength matching algorithm, offering the following advantages over existing technologies: First, by incorporating a zoom modulation system and placing the ring-shaped graded filter at the first image focal plane, the imaging area is adjustable, allowing the size of the ring-shaped graded filter with the first image focal plane to be adjusted according to system requirements. Second, a set of marker patterns is added to the original ring-shaped graded filter. The switching speed of the filter is determined by positioning these marker patterns, eliminating the need for a separate speed measurement system. Third, a wavelength matching algorithm is incorporated to reconstruct the spectral image. Synchronization between exposure time and filter switching time is eliminated, reducing the system's control precision requirements. Fourth, in hyperspectral imaging, the use of a highly detailed ring-shaped graded filter as a beam splitting module significantly improves spectral resolution, enabling high-precision three-dimensional spectral imaging. Fifth, this spectral imaging system based on a ring-shaped graded filter employs staring imaging, eliminating the need for spatial dimension sweeping, and offers advantages such as compactness, stability, and low cost. Attached Figure Description

[0017] Figure 1This is a schematic diagram of the overall system optical path structure according to an embodiment of the present invention.

[0018] Figure 2 This is a schematic diagram of the structure of an annular gradient filter according to an embodiment of the present invention.

[0019] Figure 3 A flowchart of a spectral image reconstruction method performed by an image processing module according to an embodiment of the present invention.

[0020] Figure 4 This is a flowchart illustrating the derivation of the position-time equations for each filter region in a spectral image reconstruction method operated by an image processing module according to an embodiment of the present invention.

[0021] Figure 5 A flowchart of the calibration step in a spectral image reconstruction method operated by an image processing module according to an embodiment of the present invention.

[0022] Figure 6 A flowchart of the position matching step in a spectral image reconstruction method operated by an image processing module according to an embodiment of the present invention.

[0023] The reference numerals for each element in the figure are as follows: Imaging object 1, First converging lens group 2, Circular graduated filter 3, Rotary motor 4, Motor controller 5, Second converging lens group 6, Imaging lens group 7, Camera 8, PC terminal 9; First image focal plane 301, Fan-shaped filter area 302, Marking graphic 303. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0025] An overall system diagram of a spectral imaging system based on a ring-shaped graded filter provided in one embodiment of the present invention is shown below. Figure 1 As shown, the system comprises four modules: a zoom modulation module 100, a beam splitting module 200, a collection and imaging module 300, and an image processing module 400.

[0026] The beam splitting module 200 includes an annular graded-change filter 3, which has multiple sector-shaped filter regions 302, each with a different center wavelength. The filter bands of adjacent sector-shaped filter regions 302 can be continuously distributed (i.e., connected end-to-end, or graded-change distribution), or discontinuously distributed. The sector-shaped filter regions 302 can be distributed with equal angular differences (i.e., the central angles of each sector-shaped filter region are equal), or with non-equal angular differences (i.e., not all sector-shaped filter regions have unequal central angles). The distribution of each sector-shaped filter region 302 and the center wavelength of the filter bands are known.

[0027] like Figure 2 As shown, the annular gradient filter 3 contains a plurality of fan-shaped filter areas. A graduated marking pattern 303 is printed on the substrate surface of any one of these fan-shaped filter areas. This marking pattern can be used, for example, to calibrate the position and size of the first image focal plane. Alternatively, the fan-shaped filter area bounded by the marked pattern 303 can be used as a reference filter area for the calibration. For example, the fan-shaped filter area bounded by the marked pattern 303 and with the graduations of the marked pattern 303 pointing in the same direction can be used as a reference filter area 302A.

[0028] The marked graphic is a graphic that can be used to mark measurements, such as a ruler or dots.

[0029] In addition to the annular graded filter 3, the beam splitter module 200 also includes a rotary motor 4 that drives the annular graded filter 3 to rotate and a motor controller 5 that controls the rotary motor 4. The rotary motor 4 has a circular locking part 41 at its center. The diameter and depth of the circular locking part 41 match the inner diameter of the annular graded filter 3, so that the inner contour of the annular graded filter 3 engages with the circular locking part 41 of the rotary motor 4 during installation. The motor controller 5 is compatible with the rotary motor 4 and the two are connected by wires to control parameters such as motor speed and direction. It should be understood that the beam splitter module 200 is not limited to the configuration of a rotary motor and motor controller 5; other mechanisms that can rotate the annular graded filter 3 can be used.

[0030] By driving the rotation of the annular gradient filter 3, within the fan-shaped filter area with selective bandpass bands having different center wavelengths, the incident light from the object 1, such as the light reflected from the imaging object 1 or the light emitted by the object itself, obtains the corresponding filtered light signal after passing through the fan-shaped filter area with the selective bandpass band.

[0031] The zoom modulation module 100 includes a first converging lens group and a second converging lens group. The first converging lens group is disposed in front of the annular graduated filter 3. The first converging lens group is configured such that, located in front of the annular graduated filter 3, a first image is formed on the object at the first image focal plane 301, and the size of the first image matches the size of the first image focal plane 301 on the annular graduated filter. The second converging lens group is disposed behind the annular graduated filter 3. The second converging lens group is configured to transmit the light signal carrying the information of the first image, filtered through the filtering area of ​​the annular graduated filter 3, to the rear imaging module 300. A second image is formed on the camera 8 through the imaging lens group 7 of the imaging module 300, and the size of the second image matches the size of the camera 8. The module is configured to continuously sample the light emitted from the second converging lens to form multiple frames of data. Sampling within one cycle is completed when the annular graduated filter 3 rotates one full turn.

[0032] The imaging lens group 7 and the camera 8 can be connected and fitted together, for example, via a snap ring. After they are fitted together, they are placed behind the second converging lens group 6. During the rotation of the annular graduated filter 3, each sector filter area rotates to the position of the first image focal plane. The imaging lens group 7 is used to form a second image after the first image has passed through the filter area. The wavelength of the camera 8 is matched with the different wavelengths of the annular graduated filter. The camera 8 can continuously expose the second image formed by the imaging lens group 7. Therefore, it can collect the first image information containing only the spectrum of the corresponding specific center wavelength after the incident light from the object has passed through different sector filter areas for selective bandpassing at one time. In this way, for sector filter areas without marking patterns, a second imaging of the first image can be achieved; for reference filter areas with marking patterns, imaging of both the first image and the marking pattern can be achieved.

[0033] Finally, the image processing module 400 reads and saves the multi-frame data and performs spectral image reconstruction. The image processing module 400 can be a PC-based image processing unit 9. The continuous exposure dataset acquired by the camera 8 is transmitted to the PC-based image processing unit 9 for processing via wired or wireless means.

[0034] The image processing flow of PC-side image processing unit 9 is as follows: Figure 3 As shown, it includes the following steps:

[0035] Step S201: Read multiple frames of data;

[0036] Step S202: Establish the position-time equation for each sector filter region;

[0037] Step S203: Calibrate the position and size of the focal plane of the first image.

[0038] Step S204: Position matching;

[0039] Step S205: Edge interpolation; and

[0040] Step S206: Spectral image reconstruction.

[0041] The image processing method will be explained in detail below with a specific example.

[0042] Assume a circular graded filter 3 has 50 fan-shaped filter areas with different center wavelengths, distributed at equal angles (approximately 7.2°), with adjacent fan-shaped filter areas differing in center wavelength by 6 nm. In this case, the circular graded filter has 50 filter areas. A marking pattern 303 with downward-facing graduations is printed on the base surface of the corresponding circular filter on the right side in the horizontal direction to indicate the size and position of the first image. In this embodiment, the fan-shaped filter area 302A with the graduations facing downwards is used as the reference filter area.

[0043] At this time, the annular graded filter 3 rotates at a speed of Rotate, with the direction of rotation matching the direction of the scale, i.e., clockwise. Then, when camera 8 is at a frame rate... When performing continuous exposure, the exposure time per frame is , In actual sampling, it is required ,in The average angle difference of each sector filter area is used to ensure that the marker pattern 303 can appear in at least two adjacent frames.

[0044] Step S201: Multi-frame data reading. When the marked graphics 303 are identified to appear in the same position by the image recognition method, one cycle of spectral data sampling is completed and a spectral dataset is formed. The spectral dataset is transmitted to the PC image processing unit 9 through the signal line. The PC image processing unit 9 can read and save the spectral dataset frame by frame according to the generation order of the spectral dataset to obtain data of multiple image frames.

[0045] Step S202: Establish the position-time equation for the edge lines of each sector filter area. For example... Figure 4 As shown, this step specifically includes the following steps: Step S221, find the two adjacent image frames in which the marked pattern 303 appears, and calculate the angular velocity of the annular gradient filter 3; assuming that the two adjacent image frames in which the marked pattern 303 appears are the m-th frame and the (m+1)-th frame, and the marked pattern in the m-th frame and the (m+1)-th frame is located on the first image focal plane 301, then calculate the angle through which the marked pattern 303 rotates during the time interval between the two image frames based on the data of the two image frames. At this time, the angular velocity of the annular gradient filter 3 is ,in To mark the rotation angle of graphic 303 in two adjacent image frames, The exposure time is for a single image frame. Step S222: Therefore, the position-time polar coordinate equation of the marker graphic 303 is determined as follows: The time polar coordinate equation for the position of the edge line of the reference filter region is: Step S223: Since the distribution and center wavelength of each sector filter region 302 are known, the position-time equation of the edge lines of the remaining sector filter regions is: ,in The positional angular deviation of the edge line of the sector-shaped filter area relative to the marker pattern 303 is determined by the distribution of each sector-shaped filter area 302. Therefore, in step S224, the position-time equation of any sector-shaped filter area can be determined based on the position-time equations of its two edge lines. Taking the reference filter area where the marker pattern 303 is located as an example, the position-time equation of this reference filter area is determined by the position-time equations of its two edge lines, i.e. It should be understood that obtaining the rotational speed of the annular gradient filter is not limited to the calculation method described above; other methods of obtaining the rotational speed, such as obtaining it directly through a motor controller, can also be used.

[0046] Step S203: The position and size of the first image focal plane 301 are calibrated. Specifically, the calibration includes calibrating the size and position of the first image focal plane 301 based on the position and scale of the marked pattern 303 on the first image focal plane 301, with the center of the annular graduated filter 3 as the first origin. For example... Figure 5 As shown, the calibration step can specifically include step S231, whereby when the marker pattern 303 falls within the first image focal plane 301, the vertical distance between the lower boundary center of the first image focal plane 301 and the first origin is determined according to the scale of the marker pattern 303. Next, in step S232, based on the ratio of the actual size of the scale of the marked graphic 303 to the image size of the scale in the image frame with the marked graphic, the spatial resolution of each pixel in each image frame is calibrated to determine the proportional relationship between each pixel in the image and the actual size of the object 1. The spatial resolution is defined as the ratio of the image size of the object in each frame to the actual size of the object. Then, in step S233, based on the pixel position and the spatial resolution, the first polar coordinates of any point within the first image focal plane 301, with the lower boundary center as the origin, are calibrated. The indicated position; finally, in step S234, the size and position of the first image focal plane 301 are calibrated with the center of the annular gradient filter 3 as the origin, that is, for any point in the first image focal plane, the perpendicular distance between the lower boundary center and the origin is added to obtain the second polar coordinates. The indicated location.

[0047] Step S204: Position matching. For example... Figure 6 As shown, position matching may include step S241, first using the m-th frame image as the initial frame, and then... Determine the time of any other frame, for example, the time of the k-th frame is... Step S242: The position of any pixel of the first image represented by the second polar coordinates. The position-time equation of the sector filter area corresponding to the time of each image frame In comparison, among which, Corresponding to the reference filter area, the wavelength amplitude of each pixel in each image frame in each sector filter area is determined, thereby obtaining the initial wavelength amplitude matrix. .

[0048] Step S205: Edge Interpolation. This step specifically includes interpolating the wavelength amplitude of pixels near the edge line of the sector filter area in the initial wavelength amplitude matrix of each sector filter area 302, i.e., edge pixels; for example, the wavelength amplitude of an edge pixel is optimized by performing mean interpolation with the pixels adjacent to it in the same center wavelength band. After performing the edge interpolation optimization on each edge pixel in the initial wavelength amplitude matrix, an optimized wavelength amplitude matrix can be obtained.

[0049] Step S206: Spectral Image Reconstruction. Since different pixels at the same time correspond to different center wavelengths in their respective bands, this results in wavelength misalignment in the initial or optimized wavelength amplitude matrix. Therefore, based on the optimized wavelength amplitude matrix, the amplitude signals of pixels in the same center wavelength band can be recombined according to their pixel locations to generate the image. This involves a three-dimensional spectral dataset containing height, width, and wavelength, and the reconstruction of spectral images based on this dataset.

[0050] It should be understood that all variations within the spirit of this application are within the scope of protection of this application. For example, in some embodiments, the annular gradient filter 3 is provided as having 50 fan-shaped filter areas with equal central angles, which is only an approximation. In other embodiments, the spectral resolution of the fan-shaped filter area depends on its corresponding central angle. The central angle of a single fan-shaped filter area may not exceed 18°, for example, 16°, 3.6° or smaller angles to achieve hyperspectral imaging; it is also feasible to exceed 18°, for example, 20°, 50° or larger angles to achieve multispectral imaging.

[0051] Furthermore, although in the detailed embodiment the reference filter area is defined as the fan-shaped filter area pointed to by the scale of the marker pattern 302, it can also be a fan-shaped filter area opposite to the scale direction.

[0052] It should also be understood that the shape of the filter area can be changed to other shapes depending on the shape of the annular gradient filter 3. For example, for the circular annular gradient filter 3, the filter area can be a fan-shaped filter area; while for the regular polygonal annular gradient filter 3, the filter area can be a trapezoidal filter area.

[0053] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of hardware embodiments, software embodiments, or embodiments combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage and optical storage) containing computer-usable program code.

[0054] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0055] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0056] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0057] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc.

[0058] The above description, in conjunction with preferred technical solutions, provides a further detailed explanation of the present invention and should not be construed as limiting the specific implementation of the invention to these descriptions. For those skilled in the art, simple deductions and substitutions can be made without departing from the concept of the present invention, and all such deductions and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A spectral imaging system based on an annular variable filter, characterized in that: the annular variable filter comprises a plurality of filter regions with different transmission wavelength bands, the annular variable filter provides a set of mark patterns marked with scales along the radial direction; the system comprises: a zoom modulation module composed of a first converging lens group arranged on the front side of the annular variable filter and a second converging lens group arranged on the back side of the annular variable filter; the first converging lens group is configured to form a first image of an object located on the front side of the first converging lens group on a first image focal plane on the annular variable filter; the annular variable filter is configured to rotate at least one revolution to complete a sampling period during the acquisition of spectral data, to ensure that each filter region can be rotated one by one and overlap with the first image focal plane area; the back side of the second converging lens group is provided with an imaging module composed of a camera and an imaging lens group; wherein the working wavelength band of the imaging lens group and the camera matches the wavelength of the annular variable filter; the imaging system is configured to acquire a plurality of image frames at a plurality of sampling time points within a sampling period, and generate an original spectral data set of the plurality of image frames; further comprising an image processing module, the image processing module is configured to perform the following processing steps: collect and save the original spectral data set; establish a position-time equation for each filter region according to the original spectral data set, including obtaining the rotation speed of the annular variable filter, taking the filter region where the mark pattern is located as the reference filter region, establishing the position-time equation of the reference filter region; then according to the angle difference between other filter regions and the reference filter region, and after angle compensation, the position-time equation of each filter region is obtained respectively; calibrate the position of the first image in the first image focal plane according to the mark pattern; match the position of each pixel in each image frame with the position-time equation of each filter region corresponding to the acquisition time point of the image frame; and rearrange the spectral amplitude matrix of each pixel in the original spectral data set according to the matching result to obtain a wavelength amplitude matrix, and complete spectral image reconstruction based on the wavelength amplitude matrix.

2. The annular wedge filter based spectral imaging system of claim 1, wherein, further comprising interpolation processing of the pixels on the edge of the filter region.

3. The annular wedge filter based spectral imaging system of claim 1, wherein, The mark pattern is a measurement marked pattern.

4. The annular wedge filter based spectral imaging system of claim 3, wherein, The mark pattern is a scale or a dot.

5. The annular wedge filter based spectral imaging system of claim 1, wherein, The rotation speed of the annular variable filter is obtained directly by a motor controller or by image calculation.

6. The annular wedge filter based spectral imaging system of claim 1, wherein, The first converging lens group, the second converging lens group and the imaging lens group are each composed of one or more lenses to achieve clear and high-quality imaging.

7. The annular wedge filter based spectral imaging system of claim 1, wherein, The annular variable filter (3) is driven by a micro rotary motor (4), and the micro rotary motor (4) is controlled by a motor controller (5).

8. The annular wedge filter based spectral imaging system of claim 1, wherein, The annular variable filter is a circular annular variable filter, the filter region is a fan-shaped filter region, the annular variable filter can also be a multi-edge annular variable filter, and the filter region is a trapezoidal or rectangular filter region.

9. The annular wedge filter based spectral imaging system of claim 7, wherein, The spectral resolution of the filter region depends on the central angle of the annular distribution corresponding thereto, and the central angle of the annular distribution corresponding to a single filter region is not greater than 18°.

10. The annular wedge filter based spectral imaging system of claim 9, wherein, The spectral resolution of the filter region depends on the central angle of the annular distribution corresponding thereto, and the central angle of the annular distribution corresponding to a single filter region is 16°, 3.6° or less to achieve hyperspectral imaging.

11. The annular wedge filter based spectral imaging system of claim 1, wherein, The spectral resolution of the filter region depends on the central angle of the annular distribution corresponding thereto, and the central angle of the annular distribution corresponding to a single filter region is greater than 18°.

12. The annular wedge filter based spectral imaging system of claim 11, wherein, The central angle of the annular distribution corresponding to a single filter region is 20°, 50° or more to achieve multispectral imaging.

13. The annular wedge filter based spectral imaging system of claim 1, wherein, The transmission waveband is the same in one filter region, and the transmission waveband in all filter regions on the shape-graduated filter continuously changes in the rotation direction.

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