Push-broom hyperspectral imaging device based on metasurface structure

Abstract

The invention relates to the technical field of spectral imaging, in particular to a push-broom hyperspectral imaging device based on a metasurface structure, which comprises an image taking lens, a slit, a metasurface light splitting imaging system for realizing a collimation function, a light splitting function and a focusing function in a physical light splitting manner, a sensor and an image control panel. Through mutual cooperation of the image taking lens, the slit, the metasurface spectral imaging system, the sensor and the image control panel, the device is suitable for a wavelength range supporting a deep ultraviolet band, an ultraviolet band, a visible light band, a near-infrared band, a short-wave infrared band, a medium-wave infrared band and a far-infrared band, and is high in spectrum fineness, high in resolution and high in resolution. The super-surface spectral imaging system is simple in structure and easy to achieve nanoscale or sub-nanoscale spectral resolution, meanwhile, the super-surface spectral imaging system capable of achieving the collimation function, the light splitting function and the focusing function is adopted, super-high-precision light splitting can be achieved, reconstruction calculation is not needed, meanwhile, an optical path system is optimized, the structure is compact, the size is small, and the super-surface spectral imaging system can be put into use only through small-amount debugging.

Description

Technical Field

[0001] The present invention relates to the technical field of spectral imaging, and in particular to a push-broom hyperspectral imaging device based on a metasurface structure. Background Art

[0002] Hyperspectral imaging technology is being applied in more and more fields, and the principles of imaging technology are also being updated. At present, the traditional grating + lens group solution is the most widely used, but it is bulky, the optical path system is complex, and the assembly process is difficult. Under the demand for hyperspectral industrial applications, it is difficult to improve and adapt. Therefore, the existing technology generally adopts metasurface multispectral technology. In recent years, metasurface multispectral technology has become more and more mature, but there are still many shortcomings. Its operation requires a reconstruction algorithm. When working, the reconstruction algorithm is related to the consistency of metasurface structure processing, installation consistency, and on-site environment. As a result, each device needs to adjust the reconstruction algorithm, and the calibration before use is very complicated, resulting in the unstable adaptability of the existing metasurface multispectral technology to different environments. When the environmental conditions change, there is a large uncertainty in the impact on the measurement results. At the same time, the existing metasurface multispectral bands are small, and it is difficult to accurately measure the fine spectrum of the photographed object. Therefore, the application field is relatively limited and the practicality is poor. Summary of the invention

[0003] The technical problem to be solved by the present invention is that the existing spectral imaging technology structure and optical path system are relatively complex, resulting in a relatively large volume and poor versatility. At the same time, a customized reconstruction algorithm is required during operation, the adjustment before use is very complicated, the imaging accuracy is poor, and the number of multi-spectral bands is small.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solution: a push-broom hyperspectral imaging device based on a metasurface structure, comprising:

[0005] An imaging lens, which collects light from the target area and focuses it onto the slit;

[0006] Slits, used to limit the width of incoming light;

[0007] Metasurface spectroscopic imaging system, used to realize collimation, spectroscopic and focusing functions by physical spectroscopic method;

[0008] The sensor is used to sense incident light within the corresponding wavelength range and then output a digital analog signal;

[0009] Image control board, which is used to coordinate the entire imaging process and acquire, process and transmit the image signal of the sensor;

[0010] Among them, the imaging part of the imaging lens, the slit, the metasurface spectroscopic imaging system and the imaging part of the sensor are connected along the direction of the optical path extension, the sensor is data-connected with the image control board, and the image control board is data-connected with the corresponding external device through a transmission interface. After shooting the target area, the imaging lens obtains the light signal of the entire target area to focus the light on the slit, and the linear light part of the light transmitted through the slit is given to the metasurface spectroscopic imaging system, and the metasurface spectroscopic imaging system collimates, splits and focuses the linear light part, and then obtains and focuses the light of the corresponding wavelength band to the imaging part of the sensor.

[0011] When the present invention is working, through the mutual cooperation of the imaging lens, the slit, the metasurface spectroscopic imaging system, the sensor and the image control board, the applicable wavelength range supports the deep ultraviolet band, the ultraviolet band, the visible light band, the near-infrared band, the short-wave infrared band, the medium-wave infrared band and the far-infrared band, and can support part or all of the above bands or a mixed band of several bands. The spectrum has high fineness and can easily reach the nanometer or sub-nanometer spectral resolution. At the same time, the metasurface spectroscopic imaging system that can realize the collimation function, the spectroscopic function and the focusing function is adopted, so that ultra-high precision spectrometry can be realized without the need for reconstruction calculation. At the same time, the optical path system is optimized, the structure is compact, the volume is small, and the number of parts is reduced, which is convenient for deployment and can be put into use with only a small amount of debugging.

[0012] Preferably, the metasurface spectroscopic imaging system comprises at least one metasurface component, wherein the metasurface component comprises a plurality of dielectric columns with different refractive indices and a background medium, wherein the plurality of dielectric columns are arranged in the background medium.

[0013] Preferably, the array layout between the plurality of dielectric columns is set as a one-dimensional linear array.

[0014] Preferably, the cross-sectional shape of the dielectric column is at least one of circular, square and triangular.

[0015] Preferably, the arrangement of several dielectric columns is set to be a periodic arrangement, and the several periodically arranged dielectric columns are arranged according to a period determined by a desired narrowband spectroscopy wavelength range, the size of the dielectric column is set to be smaller than the target wavelength, and the center distance between the dielectric column and the adjacent dielectric column is set to be the sum of the ratio of the target wavelength to the effective refractive index of the dielectric column and a preset correction parameter.

[0016] Preferably, the arrangement of the plurality of dielectric columns is set to be a random arrangement or a quasi-periodic arrangement, and the sizes of the plurality of dielectric columns are respectively set to be a plurality of different characteristic sizes determined according to the required broadband spectral wavelength range.

[0017] Preferably, the positions and sizes of the plurality of medium columns are arranged in the background medium in a completely random manner.

[0018] Preferably, the positions and sizes of a plurality of dielectric columns are arranged in a quasi-periodic manner in the background medium.

[0019] When the present invention is working, dielectric columns and background media with different refractive indices are used, and different dielectric column cross-sectional shape combinations and different dielectric column spacings are used to cover the required spectroscopic wavelength range. When periodically arranged dielectric columns are used, a metasurface with a specific frequency response can be created, thereby efficiently separating the light within the required wavelength range. When randomly arranged or quasi-periodically arranged dielectric columns are used, efficient spectroscopic performance in a wider frequency band can be achieved, and uniform optical response can be provided over a wide frequency band. At the same time, the quasi-periodically arranged dielectric columns can be used to further improve the good spectroscopic performance in a wide frequency band. The present invention has a wide range of applications and good versatility. By setting the array layout between a number of dielectric columns as a one-dimensional linear array, the present invention is suitable for push-scanning imaging, with high imaging accuracy and good imaging effect.

[0020] Preferably, the slit is arranged at the focal position of the imaging lens, and the imaging part of the sensor is arranged at the focal position of the metasurface spectroscopic imaging system.

[0021] Preferably, a structural member is also included, and the imaging lens, slit, metasurface spectroscopic imaging system and sensor are all fixedly mounted on the structural member.

[0022] The beneficial technical effects of the present invention include:

[0023] 1. The present invention cooperates with the imaging lens, the slit, the metasurface spectroscopic imaging system, the sensor and the image control board, and is applicable to the wavelength range supporting the deep ultraviolet band, the ultraviolet band, the visible light band, the near infrared band, the short-wave infrared band, the medium-wave infrared band and the far infrared band, and can support part or all of the above bands or a mixture of several bands. The spectrum has high fineness and can easily reach the nanometer or sub-nanometer spectral resolution. At the same time, the metasurface spectroscopic imaging system that can realize the collimation function, the spectroscopic function and the focusing function is adopted, so that ultra-high precision spectrometry can be realized without reconstruction calculation, and the optical path system is optimized at the same time, the structure is compact, the volume is small, and the number of parts is reduced, which is convenient for deployment and can be put into use with only a small amount of debugging.

[0024] 2. The present invention uses dielectric columns and background media with different refractive indices, and covers the required spectroscopic wavelength range by combining different dielectric column cross-sectional shapes and different dielectric column spacings. When periodically arranged dielectric columns are used, a metasurface with a specific frequency response can be created, thereby efficiently separating the light within the required wavelength range. When randomly arranged or quasi-periodically arranged dielectric columns are used, efficient spectroscopic performance in a wider frequency band can be achieved, and uniform optical response can be provided over a wide frequency band. At the same time, the use of quasi-periodically arranged dielectric columns can further improve the good spectroscopic performance over a wide frequency band. It has a wide range of applications and good versatility. By setting the array layout between several dielectric columns to a one-dimensional linear array, it is suitable for push-scanning imaging, with high imaging accuracy and good imaging effect.

[0025] Other features and advantages of the present invention will be disclosed in detail in the following specific embodiments and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described below in conjunction with the accompanying drawings:

[0027] Attached Figure 1 This is a disassembled diagram of a push-broom hyperspectral imaging device based on a metasurface structure. DETAILED DESCRIPTION

[0028] The technical solutions of the embodiments of the present invention are explained and described below in conjunction with the drawings of the embodiments of the present invention, but the following embodiments are only preferred embodiments of the present invention, not all. Based on the embodiments in the implementation mode, other embodiments obtained by those skilled in the art without creative work are all within the protection scope of the present invention.

[0029] In the following description, terms such as "inside", "outside", "up", "down", "left", "right", etc. that indicate directions or positional relationships are only used to facilitate the description of the embodiments and simplify the description, and do not indicate or imply that the referred device or element must have a specific direction, be constructed and operate in a specific direction. Therefore, it should not be understood as a limitation of the present invention.

[0030] Embodiment 1:

[0031] Please see attached Figure 1The present embodiment discloses a push-broom hyperspectral imaging device based on a metasurface structure, including an imaging lens 1, used to collect light from a target area and focus it on a slit 2; the slit 2, used to limit the width of the incoming light; a metasurface spectroscopic imaging system 3, used to achieve collimation, spectroscopic and focusing functions by physical spectroscopic means; a sensor 4, used to output a digital analog signal after sensing the incident light within the corresponding wavelength range; an image control board 5, used to coordinate the entire imaging process, as well as to acquire, process and transmit the image signal of the sensor 4; the following is a detailed description in conjunction with the accompanying drawings.

[0032] Please see attached Figure 1 In this embodiment, the imaging part of the imaging lens 1, the slit 2, the metasurface spectroscopic imaging system 3 and the imaging part of the sensor 4 are connected along the direction of the optical path. The sensor 4 is data-connected with the image control board 5, and the image control board 5 is data-connected with the corresponding external device through the transmission interface. After shooting the target area, the imaging lens 1 obtains the light signal of the entire target area to focus the light on the slit 2. The linear light part of the light transmitted by the slit 2 is given to the metasurface spectroscopic imaging system 3. The metasurface spectroscopic imaging system 3 collimates, splits and focuses the linear light part, and then obtains and focuses the light of the corresponding wavelength band to the imaging part of the sensor 4.

[0033] When this embodiment is working, through the mutual cooperation of the imaging lens 1, the slit 2, the metasurface spectroscopic imaging system 3, the sensor 4 and the image control board 5, the applicable wavelength range supports the deep ultraviolet band, the ultraviolet band, the visible light band, the near infrared band, the short-wave infrared band, the medium-wave infrared band and the far infrared band, and can support part or all of the above bands or a mixed band of several bands. The spectrum has high fineness and can easily reach the nanometer or sub-nanometer spectral resolution. At the same time, the metasurface spectroscopic imaging system 3 that can realize the collimation function, the spectroscopic function and the focusing function is adopted, which can realize ultra-high precision spectrometry without the need for reconstruction calculation. At the same time, the optical path system is optimized, the structure is compact, the volume is small, and the number of parts is reduced, which is convenient for deployment and can be put into use with only a small amount of debugging.

[0034] Preferably, the slit 2 is arranged at the focal position of the imaging lens 1, and the imaging part of the sensor 4 is arranged at the focal position of the metasurface spectroscopic imaging system 3. At the same time, in order to further improve the structural stability and facilitate processing and deployment, a structural part is also included, and the imaging lens 1, the slit 2, the metasurface spectroscopic imaging system 3 and the sensor 4 are all fixedly mounted on the structural part.

[0035] In a specific implementation, the metasurface spectroscopic imaging system 3 includes at least one metasurface component 31, and the metasurface component 31 includes a plurality of dielectric columns with different refractive indices and a background medium, wherein the plurality of dielectric columns are arranged in the background medium. When working, one or more metasurface components 31 can be set. When only one metasurface component 31 is set, the collimation function, the spectroscopic function and the focusing function are simultaneously realized by the metasurface component 31, so that the optical path system can be greatly simplified, and the arrangement of the metasurface spectroscopic system is also convenient, and the arrangement steps are simplified. At the same time, the array layout between the plurality of dielectric columns is set as a one-dimensional linear array, which can realize push-scanning spectral imaging, and can realize efficient spectroscopic and high spectral resolution acquisition, with high imaging accuracy and good imaging effect.

[0036] In a specific implementation, the sensor 4 may preferably be a linear array CCD or CMOS detector, which is suitable for processing data acquired line by line during push-broom imaging. Of course, any other suitable sensor device may also be used.

[0037] Embodiment 2:

[0038] Please see attached Figure 1 This embodiment provides a push-broom hyperspectral imaging device based on a metasurface structure. The same points as those in the first embodiment will not be repeated here, and the differences will be described in detail below.

[0039] Please see attached Figure 1 In this embodiment, the cross-sectional shape of the dielectric column is set to at least one of a circle, a square and a triangle. Of course, an L-shape or a C-shape can also be selected according to actual conditions to enhance the sensitivity to a specific polarization state. At the same time, the arrangement of several dielectric columns is set to a periodic arrangement, a random arrangement or a quasi-periodic arrangement.

[0040] During operation, when a periodic arrangement is adopted, a plurality of periodically arranged dielectric columns are arranged according to a period determined by the desired narrowband spectral wavelength range, and the size of the dielectric column is set to be smaller than the target wavelength, which can produce significant diffraction and resonance phenomena, and the center distance between the dielectric column and the adjacent dielectric column is set to be the sum of the ratio of the target wavelength to the effective refractive index of the dielectric column and a preset correction parameter. In specific implementation, the correction parameter can be obtained through simulation optimization. When a random arrangement or a quasi-periodic arrangement is adopted, the sizes of the plurality of dielectric columns are respectively set to a plurality of different characteristic sizes determined according to the desired broadband spectral wavelength range, and the positions and sizes of the plurality of dielectric columns are arranged in a completely random manner in the background medium, or the plurality of media The position and size of the columns are arranged in a quasi-periodic manner in the background medium, which can avoid the dependence of the periodic arrangement on a specific wavelength and achieve efficient spectroscopic analysis in a wider frequency band, thereby increasing the scope of application. In actual operation, the height of the dielectric column can be adjusted, which can further enrich the optical response mode of the metasurface spectroscopic imaging system 3, reduce the influence of the diffraction effect, and make the optical effect more uniform. At the same time, the quasi-periodic arrangement can avoid periodic repetition while retaining a certain degree of order, thereby further improving the spectroscopic performance over a wide frequency band. Preferably, the arrangement density and size of the dielectric column can also be dynamically adjusted to create a gradient refractive index distribution, which can further improve the focusing and spectroscopic effects provided by the metasurface spectroscopic imaging.

[0041] When this embodiment is working, dielectric columns and background media with different refractive indices are used, and different dielectric column cross-sectional shape combinations and different dielectric column spacings are used to cover the required spectroscopic wavelength range. When periodically arranged dielectric columns are used, a metasurface with a specific frequency response can be created, thereby efficiently separating the light within the required wavelength range. When randomly arranged or quasi-periodically arranged dielectric columns are used, efficient spectroscopic performance within a wider bandwidth can be achieved, and uniform optical response can be provided over a wide bandwidth. At the same time, the use of quasi-periodically arranged dielectric columns can further improve the good spectroscopic performance over a wide bandwidth, and has a wide range of applications and good versatility.

[0042] As a further improvement of this embodiment, the metasurface component 31 is configured to be made by nano-etching or imprinting technology. In order to improve the spectroscopic accuracy, the dielectric column is preferably made of high-refractive-index titanium dioxide or silicon nitride, while the background medium can be made of low-refractive-index glass, high-molecular polymer and other materials, which can effectively enhance the resonance effect and reduce the absorption loss.

[0043] The beneficial technical effects of this embodiment include: the present invention, through the mutual cooperation of the imaging lens, the slit, the metasurface spectroscopic imaging system, the sensor and the image control board, is applicable to the wavelength range supporting the deep ultraviolet band, the ultraviolet band, the visible light band, the near-infrared band, the short-wave infrared band, the medium-wave infrared band and the far-infrared band, and can support part or all of the above bands or a mixture of several bands. The spectrum has high fineness and can easily achieve nanometer or sub-nanometer spectral resolution. At the same time, the metasurface spectroscopic imaging system that can realize the collimation function, the spectroscopic function and the focusing function is adopted, which can realize ultra-high precision spectrometry without the need for reconstruction calculation. At the same time, the optical path system is optimized, the structure is compact, the volume is small, and the number of parts is reduced, which is convenient for deployment and can be put into use with only a small amount of debugging.

[0044] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes but is not limited to the contents described in the drawings and the above specific embodiments. Any modification that does not deviate from the functional and structural principles of the present invention will be included in the scope of the claims.

Claims

1. A push-broom hyperspectral imaging device based on a metasurface structure, characterized in that: include: An imaging lens (1) for collecting light from a target area and focusing it on a slit (2); A slit (2) is used to limit the width of incoming light; A metasurface spectroscopic imaging system (3), used to realize collimation, spectroscopic and focusing functions by means of physical spectroscopic methods; The sensor (4) is used to sense incident light within a corresponding wavelength range and then output a digital analog signal; An image control board (5) for coordinating the entire imaging process, and acquiring, processing and transmitting image signals from the sensor (4); The imaging part of the imaging lens (1), the slit (2), the metasurface spectroscopic imaging system (3) and the imaging part of the sensor (4) are connected along the direction in which the optical path extends; the sensor (4) is data-connected to an image control board (5); the image control board (5) is data-connected to a corresponding external device via a transmission interface; the imaging lens (1) acquires a light signal of the entire target area after capturing a picture of the target area to focus the light on the slit (2); the linear light part of the light transmitted through the slit (2) is given to the metasurface spectroscopic imaging system (3); the metasurface spectroscopic imaging system (3) collimates, splits and focuses the linear light part, and then acquires and focuses light of a corresponding wavelength band onto the imaging part of the sensor (4).

2. The push-broom hyperspectral imaging device based on a metasurface structure according to claim 1, characterized in that: The metasurface spectroscopic imaging system (3) comprises at least one metasurface component (31), wherein the metasurface component (31) comprises a plurality of dielectric columns with different refractive indices and a background medium, wherein the plurality of dielectric columns are arranged in the background medium.

3. The push-broom hyperspectral imaging device based on a metasurface structure according to claim 2, characterized in that: The array layout between the plurality of dielectric columns is set as a one-dimensional linear array.

4. The push-broom hyperspectral imaging device based on a metasurface structure according to claim 2, characterized in that: The cross-sectional shape of the dielectric column is at least one of a circle, a square and a triangle.

5. The push-broom hyperspectral imaging device based on a metasurface structure according to claim 2, characterized in that: The arrangement of several dielectric columns is set to be a periodic arrangement, and the several periodically arranged dielectric columns are arranged according to a period determined by a narrow-band spectral wavelength range to be achieved. The size of the dielectric column is set to be smaller than a target wavelength, and the center distance between the dielectric column and an adjacent dielectric column is set to be the ratio of the target wavelength to the effective refractive index of the dielectric column and the sum of a preset correction parameter.

6. The push-broom hyperspectral imaging device based on a metasurface structure according to claim 2, characterized in that: The arrangement of the plurality of dielectric columns is set to be a random arrangement or a quasi-periodic arrangement, and the sizes of the plurality of dielectric columns are respectively set to be a plurality of different characteristic sizes determined according to the required broadband spectral wavelength range.

7. The push-broom hyperspectral imaging device based on a metasurface structure according to claim 6, characterized in that: The positions and sizes of several medium columns are arranged in the background medium in a completely random manner.

8. The push-broom hyperspectral imaging device based on a metasurface structure according to claim 6, characterized in that: The positions and sizes of several dielectric columns are arranged in the background medium in a quasi-periodic manner.

9. The push-broom hyperspectral imaging device based on a metasurface structure according to claim 1, characterized in that: The slit (2) is arranged at the focal position of the imaging lens (1), and the imaging part of the sensor (4) is arranged at the focal position of the metasurface spectroscopic imaging system (3).

10. The push-broom hyperspectral imaging device based on a metasurface structure according to claim 1, characterized in that: It also comprises a structural component, on which the imaging lens (1), the slit (2), the metasurface spectroscopic imaging system (3) and the sensor (4) are all fixedly mounted.

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