A fast imaging spectroscopy system and method

Abstract

The present application relates to a kind of fast imaging spectral measurement system and method, and the measurement system includes imaging objective, microlens surface array, optical fiber bundle, optical fiber support, lens linear array, cylindrical lens linear array, interferometer spectrometer and data processing system. Imaging objective is imaged to target, microlens surface array divides primary image surface into N sub image surfaces, lens linear array and cylindrical lens linear array are shaped to the output light of optical fiber linear array, and corresponding interference information is obtained to interferometer spectrometer, each cylindrical lens linear array corresponds one interferometer spectrometer, and the interference information of all optical fibers is obtained by simultaneously processing the output light of corresponding cylindrical lens linear array to multiple interferometer spectrometers, and the complete spectral data cube of target is obtained by processing through data processing system. The system utilizes optical fiber bundle and lens array to split image surface, converts high-dimensional data into low-dimensional data, realizes short exposure to obtain large information quantity data cube once, and improves imaging spectral measurement speed.

Description

Technical Field

[0001] This invention relates to the field of imaging spectral measurement technology, and in particular to a rapid imaging spectral measurement system and method. Background Technology

[0002] Imaging spectrometers can acquire two-dimensional image information of a target's spatial distribution and one-dimensional spectral information of the target's resolvable units, thus obtaining a complete spectral data cube of the target. Different scenes or targets have significantly different spectral distributions. Using three-dimensional data, the detected targets can be identified and classified, or substances can be quantitatively analyzed.

[0003] Existing filter-type, dispersive, and interferometric spectrometers all require continuous scanning to obtain a complete spectral data cube of the target. Furthermore, their imaging speed is slow and they lack temporal continuity, making it difficult to detect high-speed moving targets and limiting their application scenarios. Summary of the Invention

[0004] The purpose of this invention is to provide a rapid imaging spectral measurement system and method that can obtain a cube of spectral data of a target in a single exposure, thus solving the problem of slow imaging speed of traditional imaging spectrometers.

[0005] To achieve the above objectives, in a first aspect, the present invention provides a rapid imaging spectral measurement system, comprising an imaging objective, a microlens array, an optical fiber bundle, an optical fiber support, a lens line array, a cylindrical lens line array, an interferometric spectrometer, and a data processing system, wherein:

[0006] Imaging objectives are used to image targets;

[0007] The microlens array is located downstream of the imaging objective and includes N microlenses, which are used to divide the primary image plane of the imaging objective into N sub-image planes. The number of sub-image planes is the spatial resolution of the measurement system.

[0008] The fiber bundle is supported and fixed by a fiber optic bracket. The fiber bundle consists of N fibers, and the incident end is an array. N microlenses are used to converge the light rays of N sub-image planes and transmit them into the corresponding N fibers. The output end is split into M fiber line arrays. Each fiber line array corresponds to a lens line array. Each fiber line array includes K fibers and each lens line array includes K lenses. One fiber in the fiber line array corresponds to one lens, which is used to shape the output light of the corresponding fiber into a circular spot shape. Each cylindrical lens line array corresponds to a lens line array, and each cylindrical lens line array includes K cylindrical lenses. The cylindrical lenses of each cylindrical lens line array correspond one-to-one with the lenses of the lens line array, which are used to shape the incident circular spot-shaped light rays into a linear collimated beam. The output light of the K cylindrical lenses is incident on an interferometer and then subjected to interference spectral processing to obtain K interference information.

[0009] Each cylindrical lens line array corresponds to an interferometric spectrometer. M interferometric spectrometers simultaneously perform interferometric spectral splitting on the output light of the corresponding cylindrical lens line array to obtain the interference information of each fiber. The data processing system is used to process the interference information to obtain the complete spectral data cube of the target.

[0010] Where N = M × K,

[0011] Optionally, the interferometric spectrometer is an interferometric static spectrometer.

[0012] Optionally, the fiber optic support includes multiple long rods that are inserted into the gaps between adjacent fibers along the length of the fiber.

[0013] Optionally, three long rods are inserted into each gap of adjacent optical fibers.

[0014] Optionally, the long rods are made of carbon fiber.

[0015] Secondly, the present invention also provides a rapid imaging spectral measurement method, which uses a rapid imaging spectral measurement system of any implementation of the first aspect for measurement, and the steps are as follows:

[0016] The imaging objective lens performs imaging observation of the target and images the target at an appropriate size onto the focal plane of the system, which serves as the primary image plane of the system.

[0017] The microlens array processes the primary image plane of the imaging objective, dividing it into N sub-image planes. The number of sub-image planes is the spatial resolution of the measurement system. The N microlenses respectively converge the light rays from the N sub-image planes and transmit them into the corresponding N optical fibers.

[0018] The lens line array shapes the output light of the corresponding optical fiber into a circular spot shape and then incident it onto the corresponding cylindrical lens line array. The cylindrical lens line array performs secondary shaping on the input light, making its output light a linear collimated beam. The output light of K cylindrical lenses is incident on an interferometer and then subjected to interference spectroscopy to obtain K interference fringes.

[0019] M interferometric spectrometers simultaneously perform interferometric spectral splitting on the output light of the corresponding cylindrical lens linear array to obtain the interference information of each fiber. The data processing system processes the interference information to obtain the complete spectral data cube of the target.

[0020] Optionally, the data processing system processes the interference information as follows: the spectral information of each sub-image plane is obtained through a spectral inversion algorithm, and the complete spectral data cube of the target is obtained through an image stitching and synthesis algorithm according to the arrangement order of the optical fibers.

[0021] The above-described technical solution of the present invention has the following advantages:

[0022] The rapid imaging spectral measurement system provided by this invention includes an imaging objective, a microlens array, an optical fiber bundle, an optical fiber support, a lens line array, a cylindrical lens line array, an interferometer, and a data processing system. The imaging objective performs imaging observation of the target. The microlens array divides the primary image plane of the imaging objective into N sub-image planes. The lens line array and the cylindrical lens line array shape the output light from the optical fiber line array, outputting linearly collimated light to the interferometer to obtain K interference information. Each cylindrical lens line array corresponds to one interferometer. M interferometers simultaneously perform interference and beam splitting on the output light of their corresponding cylindrical lens line arrays to obtain interference information for each optical fiber. The data processing system processes the interference information to obtain a complete spectral data cube of the target. This measurement system utilizes the optical fiber bundle and lens array to divide the image plane into multiple sub-image planes, converting high-dimensional data into low-dimensional data, achieving the acquisition of a large data cube with a single short exposure, and improving the measurement speed of imaging spectroscopy. Furthermore, the fiber bundle is supported and fixed by the fiber bracket, which prevents the fiber from being bent randomly during the light transmission process, thus avoiding the impact on the output light and causing uneven intensity distribution of the output light spot. At the same time, the stable output of the fiber can reduce the difficulty of radiation calibration and improve the accuracy of calibration. Attached Figure Description

[0023] The accompanying drawings are provided for illustrative purposes only, and the proportions and quantities of the components in the drawings may not be consistent with the actual product.

[0024] Figure 1 This is a schematic diagram of the structure of a rapid imaging spectral measurement system according to an embodiment of the present invention;

[0025] Figure 2This is a schematic diagram of the fiber optic line array, lens line array, cylindrical lens line array, and interferometric spectrometer in an embodiment of the present invention;

[0026] Figure 3 This is a schematic diagram of a fiber optic bracket supporting a fiber optic bundle in an embodiment of the present invention;

[0027] Figure 4 This is a schematic diagram of the interference information obtained after interference spectroscopy processing following the interference spectrometer in an embodiment of the present invention.

[0028] In the picture:

[0029] 1: Imaging objective lens;

[0030] 2: Microlens array;

[0031] 3: Fiber optic bundle;

[0032] 31: Optical fiber;

[0033] 4: Fiber optic bracket;

[0034] 41: Long rod;

[0035] 5: Lens line array;

[0036] 6: Cylindrical lens linear array;

[0037] 7: Interferometer;

[0038] 8: Data processing system. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] See Figures 1-3 As shown, the rapid imaging spectroscopic measurement system provided in this embodiment of the invention includes an imaging objective 1, a microlens array 2, an optical fiber bundle 3, an optical fiber support 4, a lens line array 5, a cylindrical lens line array 6, an interferometer 7, and a data processing system 8. The imaging objective 1 is used to image the target, serving as the primary image plane of the measurement system. The microlens array 2, located downstream of the imaging objective 1, includes N microlenses and is used to divide the primary image plane of the imaging objective 1 into N sub-image planes, the number of which is the spatial resolution of the measurement system.

[0041] The fiber bundle 3 is supported and fixed by the fiber optic bracket 4 to ensure the stability of the optical signal transmission in the fiber. The fiber bundle 3 consists of N fibers 31, with the incident end arranged in a closely spaced array. N microlenses are used to converge the light rays from N sub-image planes and transmit them into the corresponding N fibers 31. The exit end of the fiber bundle 3 is split into M fiber line arrays. See also... Figure 2 As shown, each fiber optic array includes K fibers 31. Each fiber optic array corresponds to a lens array 5, and one fiber 31 in each fiber optic array corresponds to one lens in the lens array 5, used to shape the outgoing light from the corresponding fiber 31 into a circular spot shape. Each cylindrical lens array 6 corresponds to one lens array 5. Specifically, each cylindrical lens array 6 includes K cylindrical lenses, and the cylindrical lenses in each cylindrical lens array 6 correspond one-to-one with the lenses in the corresponding lens array 5, used to shape the incident circular spot-shaped light into a linear collimated beam. The output light from the K cylindrical lenses is incident on an interferometer 7 and subjected to interference spectral processing to obtain K interference information, i.e., see [link to relevant documentation]. Figure 4 As shown, K interference fringes are formed on the area array detector of the interferometer 7, corresponding to the interference information of the incident light from K different optical fibers. Each fiber array corresponds to one interferometer, and M interferometers simultaneously perform interference beam splitting on the output light of the corresponding cylindrical lens array 6 to obtain the interference information of each fiber. The data processing system is used to process the interference information to obtain the complete spectral data cube of the target. Where N = M × K,

[0042] The measurement system in this embodiment utilizes an optical fiber bundle and lens array to divide the image plane into multiple sub-image planes, converting high-dimensional data into low-dimensional data. This enables the acquisition of a data cube with a large amount of information in a single short exposure, improving the measurement speed of the imaging spectrum. Furthermore, the optical fiber bundle is supported and fixed by an optical fiber bracket, preventing arbitrary bending of the optical fiber during light transmission from affecting the output light and causing uneven intensity distribution of the output light spot. At the same time, the stable output of the optical fiber light reduces the difficulty of radiometric calibration and improves the accuracy of calibration.

[0043] In this embodiment, the image-side aperture of the microlens must match the numerical aperture of the optical fiber, and the optical axis of each microlens coincides with the optical axis of the optical fiber. Each lens in the lens line array 5 corresponds one-to-one with the optical fiber 31 in the fiber line array, and the optical axis of each lens coincides with that of each optical fiber 31. The object height of the spectrometer is determined based on the limiting incident aperture angle of the interferometer 7, and the number of optical fibers K in the fiber line array can be determined based on the core diameter of the optical fiber 31.

[0044] In a preferred embodiment, the interferometric spectrometer 7 is an interferometric static spectrometer. A combination of a lens linear array and a cylindrical lens linear array is used to shape the output light from the optical fiber into linear rays. A planar array detector can perform spectral analysis on the output light from multiple optical fibers simultaneously. Furthermore, the combined use of multiple spectrometers can achieve the purpose of single-image imaging. Moreover, the interferometric spectrometer has high light throughput, which can further improve the signal-to-noise ratio of the data.

[0045] See Figure 3 As shown, in one optional embodiment, the fiber optic support 4 includes multiple long rods 41. These long rods 41 are inserted along the length of the fiber optic cable 31 into the gaps between adjacent fibers 31, forming a ring of long rods 41 surrounding the outer layer of the fiber optic cable 31. Each fiber optic cable 31 and the long rods 41 support each other, forming a stable support structure. This ensures that the final output optical signal distribution does not change due to arbitrary bending of the fiber optic cable during transmission, guaranteeing stable optical signal transmission. Preferably, three long rods 41 are inserted into each gap between adjacent fibers 31, so that each fiber optic cable 31 is fixed with at least twelve long rods 41, forming a more stable support structure. Preferably, the long rods 41 are made of carbon fiber material, which has high plasticity, high strength, and is lighter in weight.

[0046] This embodiment provides a rapid imaging spectral measurement method, which uses the rapid imaging spectral measurement system described in the above embodiment for measurement. The steps are as follows:

[0047] Step 1: The imaging objective lens performs imaging observation on the target and images the target at an appropriate size on the focal plane of the system, which serves as the primary image plane of the system.

[0048] Step 2: The microlens array processes the primary image plane of the imaging objective, dividing the entire image plane into N sub-image planes. The number of sub-image planes N is the spatial resolution of the system, i.e., N spatial elements. The microlenses perform secondary imaging of the sub-image planes to the incident end face of the fiber bundle. The image-side aperture of the microlens must match the numerical aperture of the fiber. The optical axis of each microlens coincides with the optical axis of the fiber. At the same time, the microlens array is distributed in a close arrangement and corresponds one-to-one with the fiber.

[0049] Step 3: The entrance port of the fiber bundle is matched with the microlens array. Each fiber corresponds to one microlens, so there are a total of N fibers forming the fiber bundle. The exit end of the fiber bundle splits the N fibers into M fiber line arrays. Each fiber line array is arranged in a line, and the number of fibers in each fiber line array is the same as the number of lenses in the lens line array. The fiber bundle is used to transmit the optical signal from the sub-image plane to the entrance port of the interferometer spectrometer.

[0050] Step 4: The lens line array shapes the output light of the fiber line array, directing the fiber output light into a circular spot shape onto the cylindrical lens. M fiber line arrays correspond to M lens line arrays, with each lens and fiber in a one-to-one correspondence and their optical axes coinciding. The object height of the spectrometer is determined based on the limiting incident aperture angle of the interferometer. The number of fibers K in the fiber line array can be determined based on the core diameter of the fiber, which is also the number of lenses K in the lens line array.

[0051] Step 5: The cylindrical lens line array performs secondary shaping on the input light, making its output light a linear collimated beam. The collimation characteristics of the beam ensure that the beams between the cylindrical lenses do not affect each other. The cylindrical lens line array corresponds one-to-one with the lens line array, and the number is also K.

[0052] Step Six: The linear collimated rays output from the K cylindrical lenses pass through the interferometric spectrometer, which divides the detector array into K regions, forming different interference fringes. The interference fringes of each region correspond to the interference information of each optical fiber, that is, the interference information of a spatial element in Step One. The spectral information of the spatial element can be obtained through Fourier transform. The interferometric spectrometers correspond one-to-one with the optical fiber array, and the number is M. When M interferometric spectrometers are used simultaneously, the spectral information of all elements can be obtained.

[0053] Step 7: The data processing system processes the interference information obtained in Step 6. The spectral information of each spatial element can be obtained through the spectral inversion algorithm. Based on the arrangement order of the optical fibers, the complete spectral data cube of the target is obtained through the image stitching and synthesis algorithm.

[0054] The rapid imaging spectral measurement method in this embodiment uses fiber bundles and lens arrays to split the image plane into multiple sub-image planes, converting high-dimensional data into low-dimensional data. This enables the acquisition of a data cube with a large amount of information in a single short exposure, thereby improving the measurement speed of imaging spectra.

[0055] Any aspects of this invention not described in detail are existing technology or common knowledge in the field.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that not every embodiment contains only one independent technical solution, and in the absence of conflict between solutions, the various technical features mentioned in each embodiment can be combined in any way to form other implementation methods that can be understood by those skilled in the art.

[0057] Furthermore, without departing from the scope of the present invention, modifications to the technical solutions described in the foregoing embodiments, or equivalent substitutions of some of the technical features, shall not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A rapid imaging spectral measurement system, characterized in that: It includes imaging objectives, microlens arrays, fiber bundles, fiber optic supports, lens line arrays, cylindrical lens line arrays, interferometric spectrometers, and data processing systems, among which: The imaging objective lens is used to image the target; The microlens array is located downstream of the imaging objective and includes N microlenses for dividing the primary image plane of the imaging objective into N sub-image planes. The number of sub-image planes is the spatial resolution of the measurement system. The fiber bundle is supported and fixed by a fiber optic bracket. The fiber bundle consists of N fibers, and the incident end is an array. N microlenses are used to converge the light rays from N sub-image planes and transmit them into the corresponding N fibers. The output end is split into M fiber line arrays. Each fiber line array corresponds to a lens line array. Each fiber line array includes K fibers. Each lens line array includes K lenses. One fiber in the fiber line array corresponds to one lens in the lens line array, which is used to shape the outgoing light from the corresponding fiber into a circular spot shape. Each cylindrical lens line array corresponds to a lens line array, and each cylindrical lens line array includes K cylindrical lenses. The cylindrical lenses in each cylindrical lens line array correspond one-to-one with the lenses in the lens line array, which are used to shape the incident circular spot-shaped light rays into a linear collimated beam. The output light from the K cylindrical lenses is incident on an interferometer and then subjected to interference spectral processing to obtain K interference information. Each of the cylindrical lens line arrays corresponds to one of the interferometric spectrometers. M of the interferometric spectrometers simultaneously perform interferometric spectral splitting on the output light of the corresponding cylindrical lens line arrays to obtain the interference information of each optical fiber. The data processing system is used to process the interference information to obtain a complete spectral data cube of the target. Where N = M × K, 2. The rapid imaging spectral measurement system according to claim 1, characterized in that: The interferometric spectrometer is an interferometric static spectrometer.

3. The rapid imaging spectral measurement system according to claim 1, characterized in that: The fiber optic support includes multiple long rods, which are inserted into the gaps between adjacent fibers along the length of the fiber.

4. The rapid imaging spectral measurement system according to claim 3, characterized in that: Three of the aforementioned long rods are inserted into each gap of adjacent optical fibers.

5. The rapid imaging spectral measurement system according to claim 3 or 4, characterized in that: The long rod is made of carbon fiber.

6. A rapid imaging spectral measurement method, characterized in that: The measurement is performed using the rapid imaging spectral measurement system as described in any one of claims 1-5, and the steps are as follows: The imaging objective lens performs imaging observation of the target and images the target at an appropriate size onto the focal plane of the system, which serves as the primary image plane of the system. The microlens array processes the primary image plane of the imaging objective, dividing the primary image plane into N sub-image planes. The number of sub-image planes is the spatial resolution of the measurement system. The N microlenses respectively converge the light rays from the N sub-image planes and transmit them into the corresponding N optical fibers. The lens line array shapes the output light of the corresponding optical fiber into a circular spot shape and incident it onto the corresponding cylindrical lens line array. The cylindrical lens line array performs secondary shaping on the input light, so that its output light becomes a linear collimated beam. The output light of K cylindrical lenses is incident on one of the interferometer spectrometers and then subjected to interference spectral processing to obtain K interference fringes. M interferometric spectrometers simultaneously perform interferometric spectral splitting on the output light of the corresponding cylindrical lens linear array to obtain the interference information of each optical fiber. The data processing system processes the interference information to obtain a complete spectral data cube of the target.

7. The rapid imaging spectral measurement method according to claim 6, characterized in that: The data processing system processes the interference information in the following way: the spectral information of each sub-image plane is obtained through a spectral inversion algorithm, and the complete spectral data cube of the target is obtained through an image stitching and synthesis algorithm according to the arrangement order of the optical fibers.

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