A multispectral imaging system based on variable filter area adjustment

Abstract

This invention discloses a multispectral imaging system based on variable filter area adjustment, comprising: a lens, a variable filter, a detector, and a computing device; the lens includes a front lens group and a rear lens group; the front lens group converges and collimates the target light information so that it is incident on the variable filter; the variable filter performs energy encoding on the spectral components of each channel in the incident target light information by repeatedly adjusting the light transmission area of ​​each spectral channel, and outputs the modulated target light information; the rear lens group collects the modulated target light information and directs it onto the detector; the detector detects the light intensity information at each step and sends it to the computing device; the computing device performs linear decoding on the obtained light intensity information to reconstruct the spectral components of the target at each wavelength. This invention can solve problems such as low light energy utilization, low signal-to-noise ratio, and the mutual constraint between the number of spectral channels and spatial resolution.

Description

Technical Field

[0001] This invention belongs to the field of multispectral imaging technology, specifically relating to a multispectral imaging system based on variable filter area adjustment. Background Technology

[0002] Currently, multispectral imaging has been widely used in various fields, such as agriculture, medicine, industry, cultural relic identification, and document preservation.

[0003] Regarding current multispectral imaging technology, in one existing design, Ethan Schonbrun et al. proposed a polarization-coded color (PEC) camera system, such as... Figure 1 As shown, by combining a pixelated polarizer with a chiral dispersive element, color is encoded into linear polarization states and read out in a single exposure. Its structure includes a pixelated polarizer composed of four linear micro-polarizers and a chiral dispersive element. This camera can capture three-color images from visible to near-infrared wavelengths, can photograph under artificial lighting and sunlight, is suitable for single-frame acquisition of fast-moving objects, and can also be applied in imaging systems and microscopes to quantify hemoglobin in biological samples. However, the number of detectable spectral channels is extremely limited; when the pixelated polarizer has more than three states, the number of resolvable spectral channels cannot be increased, and it is difficult to independently retrieve four spectra in a single exposure. In summary, the PEC camera has advantages such as reconfigurable spectral response, but its spectral detection capabilities need further improvement.

[0004] In another existing design, the SHUJIONO team proposed a snapshot-style multispectral imaging technique, such as... Figure 2 As shown, this technology combines an imaging lens with multispectral and polarization filters with a pixel-level color polarization image sensor. This image sensor acquires a polarization-coded image of the multispectral image mixture, and then a crosstalk cancellation decoding algorithm reconstructs the multispectral polarization image of the target. This technology only requires a single exposure of the image sensor to acquire the target's multispectral information. However, due to the limited number of encoding times and parameters, the encoding capability is weak, resulting in a limited number of spectral channels for final decoding and reconstruction, not exceeding nine. This significantly restricts the system's ability to detect spectral details of the target. Furthermore, this technology requires a color polarization image sensor to obtain stronger information decoding capabilities, and it demands that the image formed by each point on the target after passing through the imaging lens must correspond to a set of RGB color polarization pixel blocks on the color polarization image sensor. That is, 16 sub-pixels (4*4) of the color polarization detector correspond to one pixel on the black and white detector. Therefore, the reconstructed multispectral polarization image has low spatial resolution, which is not conducive to accurately displaying the target's detailed features.

[0005] Currently, most traditional multispectral imaging techniques employ multispectral imaging methods based on filter wheels, acousto-optic tunable filters, or liquid crystal tunable filters. These systems acquire an image of the target in a single spectral channel for each measurement. By switching the spectral channels of the acousto-optic or liquid crystal tunable filter, or by rotating the filter wheel, images of the target in different spectral channels can be acquired. Because this method can only measure the image of the target in a single spectral channel at a time, the utilization rate of incident light energy is low, especially in spectral bands with low detector spectral responsivity (such as near blue light), resulting in a low signal-to-noise ratio in the acquired spectral images.

[0006] With the development of microelectromechanical systems (MEMS) technology, multi-channel spectral filtering pixel array chips capable of pixel-level integration with detectors have emerged. These chips integrate a large number of micro- and nano-scale spectral filtering units, enabling simultaneous imaging of multiple spectral channels. Currently, specifications such as 2*2 four-channel, 3*3 nine-channel, and 4*4 sixteen-channel are available. However, this method requires treating each multi-channel spectral filtering unit as a macro-pixel, corresponding to multiple pixels on the detector, with one macro-pixel corresponding to one object point. This leads to a trade-off between the number of spectral channels and spatial resolution; the more spectral channels, the more detector pixels are contained within the macro-pixel, resulting in lower spatial resolution.

[0007] In summary, existing multispectral imaging technologies have various limitations, such as low light energy utilization, low signal-to-noise ratio, and the mutual constraint between the number of spectral channels and spatial resolution, which affect the development and application of multispectral imaging technologies. Summary of the Invention

[0008] To address the aforementioned problems in the prior art, this invention provides a multispectral imaging system based on variable filter area adjustment. The technical problem to be solved by this invention is achieved through the following technical solution:

[0009] A multispectral imaging system based on variable filter area adjustment includes: a lens, a variable filter, a detector, and a computing device; the lens includes a front lens group and a rear lens group, respectively disposed in front of and behind the aperture stop, each including multiple lenses; the variable filter is a multi-channel narrowband filter, disposed at the aperture stop of the lens, and the light transmission area and gating wavelength of each spectral channel are controllable; the detector is disposed at the image plane of the lens;

[0010] The front lens group is used to converge and collimate the target light information so that it is incident on the variable filter;

[0011] The variable filter is used to encode the energy of each channel spectral component in the incident target light information by adjusting the light transmission area of ​​each spectral channel multiple times, and output the modulated target light information.

[0012] The rear lens group is used to collect the modulated target light information and project it onto the detector.

[0013] The detector is used to detect the light intensity information obtained by focusing the rear lens and send it to the computing device.

[0014] The computing device is used to linearly decode the light intensity information obtained multiple times to restore the spectral components of the target at each wavelength.

[0015] In one embodiment of the present invention, the variable filter adjusts the light transmission area of ​​each spectral channel in multiple modulations according to a pre-set light transmission area matrix; wherein, the number of rows in the light transmission area matrix represents the number of modulations, and each element in each row represents the light transmission area of ​​each spectral channel in the corresponding modulation; the light transmission area matrix is ​​a full-rank matrix.

[0016] In one embodiment of the present invention, in any modulation of the variable filter, each spectral channel uses its light-passing area, transmittance and gating center wavelength to encode the spectral components of the incident target light information belonging to that channel with energy.

[0017] In one embodiment of the present invention, for any modulation of the variable filter, the light intensity information detected by the detector is the sum of the energy encoding results of all spectral channels in that modulation of the variable filter, expressed by the formula:

[0018]

[0019] Where O(x,y) represents the light emitted from a point (x,y) on the target; the variable filter has n spectral channels, and the gating center wavelength of the i-th spectral channel is λ. i Transmittance is T i (λ), the light-transmitting area is S i S i T i O(x,y,λ i ) represents the energy encoding result of the i-th spectral channel, i = 1 to n; O(x * ,y * ) represents the light intensity information detected by the detector.

[0020] In one embodiment of the present invention, the process by which the computing device performs linear decoding on the light intensity information obtained multiple times to reconstruct the spectral components of the target at each wavelength includes:

[0021] A light intensity information matrix is ​​obtained based on the light intensity information obtained multiple times;

[0022] The first matrix is ​​obtained by multiplying the inverse of the light-transmitting area matrix with the light intensity information matrix.

[0023] Divide the components in the first matrix by the transmittance of the corresponding spectral channel to obtain the spectral components of the target at the corresponding wavelength.

[0024] In one embodiment of the present invention, obtaining the light intensity information matrix based on the light intensity information obtained multiple times includes:

[0025] Based on the light intensity information obtained from n modulations, the following system of equations is derived:

[0026]

[0027] Rewriting the above equations in matrix form yields the light intensity information matrix, represented as:

[0028]

[0029] Where O(x,y) represents the light emitted from a point (x,y) on the target; the variable filter has n spectral channels, and the gating center wavelength of the i-th spectral channel is λ. i Transmittance is T i (λ), the light-transmitting area is S i S i T i O(x,y,λ i ) represents the energy encoding result of the i-th spectral channel, where i = 1 to n; The light transmission area matrix is ​​O. i (x * ,y * ) represents the light intensity information detected by the detector after the i-th modulation.

[0030] In one embodiment of the present invention, the first matrix is ​​represented as:

[0031]

[0032] The spectral components of the target at each wavelength are represented as follows:

[0033] O(x,y,λ i ) = T i O(x,y,λ i ) / T i ;

[0034] Where O(x,y,λ) i Let λ represent the light emitted from a point (x,y) on the target, with a wavelength of λ. i The spectral components below.

[0035] In one embodiment of the present invention, the detector is a monochrome detector.

[0036] This invention proposes a multispectral imaging system based on variable filter area adjustment. By repeatedly adjusting the light-transmitting area of ​​each spectral channel on the filter, the spectral components of each channel in the incident target light are encoded multiple times using energy. Then, the acquired multiple sets of spectral mixture information are linearly decoded to reconstruct the multiple spectral components of the target. Compared with the prior art, this invention has the following advantages:

[0037] 1. Higher energy efficiency and higher signal-to-noise ratio

[0038] This invention encodes and decodes spectral information by adjusting the light-transmitting area of ​​different channels of a variable filter, enabling efficient energy utilization. Specifically, by rationally adjusting the light-transmitting area of ​​different channels of the variable filter, light of different wavelengths can be effectively passed through and modulated as needed, improving the overall energy utilization efficiency of the system. Simultaneously, this invention also improves the signal-to-noise ratio (SNR). Through a unique encoding and decoding method based on variable filter area adjustment, it reduces noise interference and improves signal quality when processing spectral information. For example, rationally controlling the light-transmitting area of ​​different channels of the variable filter can make the light information received by the detector purer, reducing unnecessary noise components and thus improving the SNR. This results in superior multispectral imaging effects.

[0039] 2. The number of spectral channels and spatial resolution are not mutually restrictive.

[0040] The spatial resolution of this invention is not limited by the number of spectral channels. This system does not have a multi-channel spectral filtering pixel array chip integrated at the pixel level in front of the detector; therefore, the spatial resolution is only affected by the detector and is not constrained by the number of spectral channels.

[0041] 3. The number of spectral channels can be flexibly adjusted.

[0042] This invention offers greater flexibility in terms of the number of spectral channels. By adjusting the light-transmitting area of ​​different channels of the variable filter, the number of spectral channels can be flexibly adjusted according to actual needs, without being limited by fixed encoding times and encoding parameters. This allows it to better meet different requirements for detecting the spectral details of the target.

[0043] 4. The system structure is simpler.

[0044] This invention is based on a system constructed from three main components: a lens, a variable filter, and a detector. The structure is simpler and clearer, reducing the complexity and cost of the system, while also improving its stability and reliability. Attached Figure Description

[0045] Figure 1This is a schematic diagram of an existing polarization-coded color (PEC) camera system;

[0046] Figure 2 This is a schematic diagram of an existing snapshot multispectral imaging system.

[0047] Figure 3 This is a schematic diagram of the structure of a multispectral imaging system based on variable filter area adjustment, provided in an embodiment of the present invention.

[0048] Figure 4 This is a schematic diagram illustrating an understanding of the variable filter structure provided in an embodiment of the present invention. Detailed Implementation

[0049] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0050] This invention provides a multispectral imaging system based on variable filter area adjustment, such as... Figure 3 As shown, it may include:

[0051] The system comprises a lens, a variable filter, a detector, and a computing device; the lens includes a front lens group and a rear lens group, respectively positioned in front of and behind the aperture stop, each including multiple lenses; the variable filter is a multi-channel narrowband filter, positioned at the aperture stop of the lens, and the light transmission area and gating wavelength of each spectral channel are controllable; the detector is positioned at the image plane of the lens.

[0052] The front lens group is used to converge and collimate the target light information so that it is incident on the variable filter;

[0053] The variable filter is used to encode the energy of each channel spectral component in the incident target light information by adjusting the light transmission area of ​​each spectral channel multiple times, and output the modulated target light information.

[0054] The rear lens group is used to collect the modulated target light information and project it onto the detector.

[0055] The detector is used to detect the light intensity information obtained by focusing the rear lens and send it to the computing device.

[0056] The computing device is used to linearly decode the light intensity information obtained multiple times to restore the spectral components of the target at each wavelength.

[0057] In this embodiment of the invention, the structural design of the multispectral imaging system based on variable filter area adjustment ensures the effective transmission and processing of optical information in the system, laying the foundation for achieving efficient spectral encoding and decoding.

[0058] In this embodiment of the invention, the target can be any object. Figure 3 The boxes within the diagram represent the components of this multispectral imaging system based on variable filter area adjustment. These mainly include a lens, a variable filter, a detector, and a computing device. The lens is further divided into a front lens group and a rear lens group, with the front lens group positioned in front of the aperture stop and the rear lens group positioned behind it. Both the front and rear lens groups consist of multiple lenses. For the front and rear lens groups, the multiple lenses can be coaxially arranged, and the size and spacing of each lens can be set as needed. In this embodiment, the lens type in the front and rear lens groups is not limited; for example, spherical lenses and aspherical lenses can be used.

[0059] The front lens is responsible for focusing and collimating the target light information so that it is incident on the variable filter.

[0060] A variable filter, positioned at the aperture stop of a lens, is a multi-channel narrowband filter with controllable light-passing areas and gated wavelengths for different channels. Its controllable channel size and gated wavelength allow for selective transmission and modulation of different wavelengths of light as needed. By rationally dividing the spectral channels, each channel has a specific gated center wavelength, transmittance, and light-passing area, thus achieving precise encoding of spectral information. In use, the variable filter is divided into n spectral channels, each with a gated center wavelength of λ. i (i = 1 to n), transmittance is T i (λ), the area of ​​the light-transmitting aperture is S i Please refer to a schematic diagram of the variable filter structure. Figure 4 As shown. The variable filter can change the light transmission area and gating wavelength of different channels by means of voltage adjustment, or by using some new electronic control materials. Any method that can change the light transmission area of ​​each spectral channel of the filter can be included in the protection scope of this invention, and is not limited here.

[0061] The variable filter modulates the incident target light information multiple times. Specifically, the variable filter adjusts the light transmission area of ​​each spectral channel during multiple modulations based on a pre-set light transmission area matrix; the light transmission area matrix is ​​a full-rank matrix.

[0062] In this embodiment of the invention, the light transmission area matrix can be pre-designed and determined based on the requirements of a full-rank matrix and the number of spectral channels n for subsequent use. In this embodiment, S represents the light transmission area matrix, specifically as follows:

[0063]

[0064] The number of rows in the light transmission area matrix represents the modulation number, and each element in each row represents the light transmission area of ​​each spectral channel in the corresponding modulation.

[0065] Specifically, in any modulation of the variable filter, the light transmission area of ​​each spectral channel is set according to the values ​​of each element in the corresponding row of the light transmission area matrix. Each spectral channel uses its light transmission area, transmittance, and gated center wavelength to encode the energy of the spectral components belonging to that channel in the incident target light information.

[0066] Assuming the light emitted from a point (x,y) on the target is O(x,y), taking the i-th spectral channel as an example, the encoded result after energy encoding can be represented as S. i T i O(x,y,λ i After this modulation, the encoded results from all spectral channels are combined to obtain the modulated target light information.

[0067] The rear lens group is used to collect the modulated target light information and project it onto the detector.

[0068] The detector is used to detect the light intensity information obtained by focusing the light through the rear lens and send it to the computing device; in one optional embodiment, the detector is a monochrome detector, which can be implemented using existing commercial products.

[0069] The computing device is used to linearly decode the light intensity information obtained multiple times to restore the spectral components of the target at each wavelength.

[0070] In this embodiment of the invention, the computing device may be a computer or other device or component with data processing capabilities.

[0071] For ease of understanding, the following is combined with Figure 4 The subsequent processing of the detector will be explained.

[0072] Approximating the spectral curves near the center wavelength of each spectral channel as rectangular functions, for any modulation of the variable filter, the light intensity information detected by the detector is the sum of the energy encoding results of all spectral channels in that modulation, expressed by the formula:

[0073]

[0074] Where O(x,y) represents the light emitted from a point (x,y) on the target; the variable filter has n spectral channels, and the gating center wavelength of the i-th spectral channel is λ. i Transmittance is T i(λ), the light-transmitting area is S i S i T i O(x,y,λ i ) represents the energy encoding result of the i-th spectral channel, O(x,y,λ) i O(x*,y*) represents the light at (x,y) with a gating center wavelength of λi, where i = 1 to n; O(x*,y*) represents the light intensity information detected by the detector.

[0075] The process by which the computing device linearly decodes the light intensity information obtained multiple times to reconstruct the spectral components of the target at each wavelength includes:

[0076] 1) Obtain the light intensity information matrix based on the light intensity information obtained multiple times;

[0077] Specifically, based on the light intensity information obtained from n modulations, the following system of equations is derived:

[0078]

[0079] Rewriting the above equations in matrix form yields the light intensity information matrix, represented as:

[0080]

[0081] in, Let be the light transmission area matrix.

[0082] 2) Calculate the inverse of the light-transmitting area matrix and multiply it with the light intensity information matrix to obtain the first matrix;

[0083] Specifically, the first matrix is ​​represented as:

[0084]

[0085] The left side of the equals sign is the first matrix, where each row corresponds to a spectral channel, that is, a gating center wavelength.

[0086] 3) Divide the components in the first matrix by the transmittance of the corresponding spectral channel to obtain the spectral components of the target at the corresponding wavelength.

[0087] The spectral components of the target at each wavelength are represented as follows:

[0088] O(x,y,λ i ) = T i O(x,y,λ i ) / T i ;

[0089] Where O(x,y,λ) iLet λ represent the light emitted from a point (x,y) on the target, with a wavelength of λ. i The spectral components below.

[0090] In this embodiment of the invention, the variable filter encodes light information at different wavelengths through area changes. Specifically, when light emitted from a point on the target enters the system, it first passes through the focusing and collimation of the front lens group, and then reaches the variable filter. The variable filter is divided into multiple spectral channels, each with its specific gated center wavelength, transmittance, and light-passing area. By approximating the spectral curves near the center wavelength of each spectral channel as rectangular functions, different combinations of light information can be obtained through multiple modulation shots by changing the size of the light-passing area of ​​different spectral channels. This method of encoding light information at different wavelengths through area changes allows spectral information to be encoded and recorded in a unique way, providing the possibility for subsequent decoding and spectral information reconstruction.

[0091] For example, when the light-transmitting area of ​​different channels is changed, the energy of light of different wavelengths passing through will change, and thus the light intensity received on the detector will also change accordingly. By taking multiple images of light information under different area settings, a model of the relationship between spectral information and light-transmitting area can be established, thereby enabling effective encoding of spectral information.

[0092] Based on the above encoding process, during decoding, the light information received by the detector is analyzed and processed. Using the established relationship model between spectral information and light-transmitting area, the original spectral information can be reconstructed. Specifically, the light information received by the detector is processed according to a certain algorithm and mathematical model. For example, light information obtained from multiple images is combined into a system of equations and rewritten in matrix form. Given that the light-transmitting area matrix is ​​a full-rank matrix, the input light of each channel can be further represented, thereby enabling the reconstruction of the components of light emitted from a point on the target at different wavelengths, ultimately achieving the interpretation of the entire spectral information.

[0093] This approach to optical information interpretation is key to the accurate acquisition of spectral information by a multispectral imaging system based on variable filter area adjustment. It ensures that the system can effectively recover the original spectral information from the encoded optical information, thereby achieving accurate spectral imaging of the target.

[0094] In summary, this invention proposes a multispectral imaging system based on variable filter area adjustment. By repeatedly adjusting the light transmission area of ​​each spectral channel on the filter, the spectral components of each channel in the incident target light are encoded multiple times. Then, the multiple sets of spectral mixed information are linearly decoded to restore the multiple spectral components of the target.

[0095] Compared with the prior art, the present invention has the following advantages:

[0096] 1. Higher energy efficiency and higher signal-to-noise ratio

[0097] This invention encodes and decodes spectral information by adjusting the light-transmitting area of ​​different channels of a variable filter, enabling efficient energy utilization. Specifically, by rationally adjusting the light-transmitting area of ​​different channels of the variable filter, light of different wavelengths can be effectively passed through and modulated as needed, improving the overall energy utilization efficiency of the system. Simultaneously, this invention also improves the signal-to-noise ratio (SNR). Through a unique encoding and decoding method based on variable filter area adjustment, it reduces noise interference and improves signal quality when processing spectral information. For example, rationally controlling the light-transmitting area of ​​different channels of the variable filter can make the light information received by the detector purer, reducing unnecessary noise components and thus improving the SNR. This results in superior multispectral imaging effects.

[0098] 2. The number of spectral channels and spatial resolution are not mutually restrictive.

[0099] The spatial resolution of this invention is not limited by the number of spectral channels. This system does not have a multi-channel spectral filtering pixel array chip integrated at the pixel level in front of the detector; therefore, the spatial resolution is only affected by the detector and is not constrained by the number of spectral channels.

[0100] 3. The number of spectral channels can be flexibly adjusted.

[0101] This invention offers greater flexibility in terms of the number of spectral channels. By adjusting the light-transmitting area of ​​different channels of the variable filter, the number of spectral channels can be flexibly adjusted according to actual needs, without being limited by fixed encoding times and encoding parameters. This allows it to better meet different requirements for detecting the spectral details of the target.

[0102] 4. The system structure is simpler.

[0103] This invention is based on a system constructed from three main components: a lens, a variable filter, and a detector. The structure is simpler and clearer, reducing the complexity and cost of the system, while also improving its stability and reliability.

[0104] It should be noted that, in the description of this invention, the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0105] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0106] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0107] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A multispectral imaging system based on variable filter area adjustment, characterized in that, include: The system comprises a lens, a variable filter, a detector, and a computing device; the lens includes a front lens group and a rear lens group, respectively positioned in front of and behind the aperture stop, each including multiple lenses; the variable filter is a multi-channel narrowband filter, positioned at the aperture stop of the lens, and the light transmission area and gating wavelength of each spectral channel are controllable; the detector is positioned at the image plane of the lens. The front lens group is used to converge and collimate the target light information so that it is incident on the variable filter; The variable filter is used to encode the energy of each channel spectral component in the incident target light information by adjusting the light transmission area of ​​each spectral channel multiple times, and output the modulated target light information. The rear lens group is used to collect the modulated target light information and project it onto the detector. The detector is used to detect the light intensity information obtained by focusing the rear lens and send it to the computing device. The computing device is used to linearly decode the light intensity information obtained multiple times, and to reconstruct the spectral components of the target at each wavelength; wherein... The variable filter adjusts the light transmission area of ​​each spectral channel during multiple modulations based on a pre-set light transmission area matrix; wherein, the number of rows in the light transmission area matrix represents the number of modulations, and each element in each row represents the light transmission area of ​​each spectral channel during the corresponding modulation; the light transmission area matrix is ​​a full-rank matrix. In any modulation of the variable filter, each spectral channel uses its light-transmitting area, transmittance, and gating center wavelength to encode the spectral components belonging to that channel in the incident target light information.

2. The multispectral imaging system based on variable filter area adjustment according to claim 1, characterized in that, For any modulation of the variable filter, the light intensity information detected by the detector is the sum of the energy encoding results of all spectral channels in that modulation, expressed by the formula: Where O(x,y) represents the light emitted from a point (x,y) on the target; the variable filter has n spectral channels, and the gating center wavelength of the i-th spectral channel is λ. i Transmittance is T i (λ), the light-transmitting area is S i S i T i O(x,y,λ i ) represents the energy encoding result of the i-th spectral channel, i = 1 to n; O(x * ,y * ) represents the light intensity information detected by the detector.

3. The multispectral imaging system based on variable filter area adjustment according to claim 1 or 2, characterized in that, The computing device performs linear decoding on the light intensity information obtained multiple times to reconstruct the spectral components of the target at each wavelength, including: A light intensity information matrix is ​​obtained based on the light intensity information obtained multiple times; The first matrix is ​​obtained by multiplying the inverse of the light-transmitting area matrix with the light intensity information matrix. Divide the components in the first matrix by the transmittance of the corresponding spectral channel to obtain the spectral components of the target at the corresponding wavelength.

4. The multispectral imaging system based on variable filter area adjustment according to claim 3, characterized in that, The process of obtaining a light intensity information matrix based on multiple obtained light intensity information includes: Based on the light intensity information obtained from n modulations, the following system of equations is derived: Rewriting the above equations in matrix form yields the light intensity information matrix, represented as: Where O(x,y) represents the light emitted from a point (x,y) on the target; the variable filter has n spectral channels, and the gating center wavelength of the i-th spectral channel is λ. i Transmittance is T i (λ), the light-transmitting area is S i S i T i O(x,y,λ i ) represents the energy encoding result of the i-th spectral channel, where i = 1 to n; The light transmission area matrix is ​​O. i (x * ,y * ) represents the light intensity information detected by the detector after the i-th modulation.

5. The multispectral imaging system based on variable filter area adjustment according to claim 4, characterized in that, The first matrix is ​​represented as: The spectral components of the target at each wavelength are represented as follows: O(x,y,λ i )=T i O(x,y,λ i ) / T i ; Where O(x,y,λ) i Let λ represent the light emitted from a point (x,y) on the target, with a wavelength of λ. i The spectral components below.

6. The multispectral imaging system based on variable filter area adjustment according to claim 1, characterized in that, The detector is a monochrome detector.

Images