A remote sensing imaging system for simultaneous monitoring of vegetation composite parameters

Abstract

This invention discloses a remote sensing imaging system for simultaneous monitoring of vegetation composite parameters. Incident parallel light is imaged by an off-axis three-reflector telescope system, a field-of-view scanning component, and a field-of-view segmentation element, then split into two fields of view. One field of view is imaged onto the focal plane of the first detector's focal plane circuit component after passing through a relay optics system and a low-distortion, high-dispersion beam splitting system. The other field of view is imaged onto the focal plane of the second detector's focal plane circuit component after passing through a low-distortion, high-resolution beam splitting system. Integrated electronic components drive the first and second detector focal plane circuit components respectively to perform photoelectric signal conversion, completing hyperspectral and superspectral imaging detection, thus achieving simultaneous remote sensing imaging for monitoring vegetation composite parameters. The system of this invention solves the problem of asynchronous measurement of key elements in existing land surface vegetation parameter detection payloads, which limits the monitoring accuracy of vegetation health status and carbon sequestration capacity due to the inability to simultaneously detect multiple parameters.

Description

Technical Field

[0001] This invention belongs to the field of ecological parameter detection technology, and in particular relates to a remote sensing imaging system for synchronous monitoring of vegetation composite parameters. Background Technology

[0002] Various parameters of vegetation canopy are crucial for terrestrial ecological governance, carbon sequestration, and precision agricultural management, playing a significant role in implementing the "Two Mountains" theory and achieving "dual carbon" (carbon sequestration and carbon emissions). In remote sensing, vegetation canopy parameters are primarily detected through active and passive optical methods and radar. Besides structural parameters, pigments, nitrogen, water content, photosynthesis, xylem content, leaf area, plant species, and even soil components are currently obtained using passive optical detection methods. While photosynthetic efficiency, except for photosynthetic efficiency, can be precisely detected using hyperspectral imaging, photosynthetic efficiency, a key element in carbon sequestration and an important reference for precision agricultural management, cannot be obtained solely through direct measurement of plant pigments. The most effective detection method is to simultaneously detect plant pigments, non-photochemical quenching (NPQ), and fluorescence spectroscopy (SIF), and then classify and identify the vegetation.

[0003] Because the spectral bands required for the aforementioned detection elements differ and their spectral resolution varies by tens of times, the spatial resolution and swath width of the corresponding spectral imagers also differ significantly. Currently, no satellite remote sensing payload has the capability to simultaneously detect the aforementioned vegetation parameters, necessitating the fusion of data from multiple payloads. Using hyperspectral and hyperspectral payloads from different platforms for inversion inevitably faces the influence of different observation directions, mismatched spatial resolutions, and different imaging times, leading to errors in the inversion of actual ecological parameters, especially carbon sink parameters. Summary of the Invention

[0004] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a remote sensing imaging system for synchronous monitoring of vegetation composite parameters. This system can meet the requirements of satellite platforms for high-precision comprehensive monitoring of the health status and carbon sequestration capacity of land surface and nearshore vegetation. Moreover, its detection capability is far superior to that of existing land surface vegetation parameter detection payloads, comprehensively improving the detection capability of vegetation parameters. It solves the problem that the key elements of existing land surface vegetation parameter detection payloads are not synchronized, resulting in the monitoring accuracy of vegetation health status and carbon sequestration capacity being limited by the inability to detect multiple parameters synchronously.

[0005] To address the aforementioned technical problems, this invention discloses a remote sensing imaging system for synchronous monitoring of vegetation composite parameters, comprising: an off-axis three-mirror telescope system, a field-of-view scanning component, a field-of-view segmentation element, a relay optical system, a low-distortion high-dispersion beam splitting system, a low-distortion high-resolution beam splitting system, a first detector focal plane circuit assembly, a second detector focal plane circuit assembly, and an integrated electronics assembly; the relay optical system, the low-distortion high-dispersion beam splitting system, and the first detector focal plane circuit assembly constitute a fluorescence detection channel; the low-distortion high-resolution beam splitting system and the second detector focal plane circuit assembly constitute a visible light near-infrared channel; wherein, incident parallel light is imaged by the off-axis three-mirror telescope system and the field-of-view scanning component... After reflection, the image is divided into two fields of view by a field-of-view splitting element. One field of view is imaged to slit A of a low-distortion, high-dispersion beam splitting system after passing through a relay optical system. The image is then split by the low-distortion, high-dispersion beam splitting system and imaged onto the detector focal plane of the first detector focal plane circuit assembly. The other field of view is imaged to slit B of a low-distortion, high-resolution beam splitting system. The image is then split by the low-distortion, high-resolution beam splitting system and imaged onto the detector focal plane of the second detector focal plane circuit assembly. Finally, the integrated electronics components drive the first and second detector focal plane circuit assemblies to perform photoelectric signal conversion, completing hyperspectral and superspectral imaging detection and realizing remote sensing imaging for simultaneous monitoring of vegetation composite parameters.

[0006] In the aforementioned vegetation composite parameter synchronous monitoring remote sensing imaging system, the off-axis three-reflector telescope system is used to image the radiation received by the entrance pupil of the spectral detector onto the slits of the low-distortion high-dispersion spectral system and the low-distortion high-resolution spectral system, respectively, after passing through the field-of-view scanning component and the field-of-view segmentation element.

[0007] In the aforementioned vegetation composite parameter synchronous monitoring remote sensing imaging system, the field-of-view scanning component is used to fold the optical path and adjust the optical axis in front of the image of the off-axis three-mirror telescope system, and to achieve super-resolution spectral imaging through field-of-view scanning.

[0008] In the aforementioned vegetation composite parameter synchronous monitoring remote sensing imaging system, the field-of-view splitting element is used to divide the outgoing light from the field-of-view scanning component into two fields of view in front of the image of the off-axis three-reflector telescope system, which are then refracted to the fluorescence detection channel and the visible and near-infrared channel, respectively.

[0009] In the aforementioned vegetation composite parameter synchronous monitoring remote sensing imaging system, the relay optical system is used to convert the focal length of the off-axis three-reflector telescope system into a focal length that matches the fluorescence hyperspectral imaging.

[0010] In the aforementioned vegetation composite parameter synchronous monitoring remote sensing imaging system, the low-distortion high-dispersion spectral system is used to perform hyperspectral resolution spectral dispersion on one of the fields of view of the off-axis three-reflector telescope system and to image on the detector focal plane of the first detector focal plane circuit assembly.

[0011] In the aforementioned vegetation composite parameter synchronous monitoring remote sensing imaging system, the low-distortion high-resolution spectral system is used to perform high spatial resolution spectral dispersion on another field of view of the off-axis three-reflector telescope system image plane, and to image on the detector focal plane of the second detector focal plane circuit assembly.

[0012] In the aforementioned vegetation composite parameter synchronous monitoring remote sensing imaging system, the first detector focal plane circuit assembly is used to perform spectral imaging of the fluorescence detection channel on the image plane of the low-distortion, high-dispersion spectral system.

[0013] In the aforementioned vegetation composite parameter synchronous monitoring remote sensing imaging system, the second detector focal plane circuit assembly is used to perform spectral imaging of the visible and near-infrared channels on the image plane of the low-distortion high-resolution spectral system.

[0014] In the aforementioned vegetation composite parameter synchronous monitoring remote sensing imaging system, integrated electronic components are used to power the field-of-view scanning component, the first detector focal plane circuit component, and the second detector focal plane circuit component, and to send drive signals to the field-of-view scanning component, the first detector focal plane circuit component, and the second detector focal plane circuit component.

[0015] The present invention has the following advantages:

[0016] (1) This invention discloses a remote sensing imaging system for synchronous monitoring of vegetation composite parameters. By sharing an off-axis three-reflector telescope system, a field-of-view scanning component, and a field-of-view segmentation element, it splits the visible light near-infrared channel and the fluorescence detection channel to achieve simultaneous measurement of multiple parameters such as vegetation SIF, species, and pigment content. This improves the comprehensiveness and synchronization rate of vegetation canopy data acquisition during remote sensing detection, thereby comprehensively analyzing the photosynthetic efficiency of vegetation and improving the monitoring accuracy of satellite remote sensing on vegetation health status and carbon sequestration capacity. It solves the problem that the key elements of existing land surface vegetation parameter detection payloads are not synchronized, which limits the monitoring accuracy of vegetation health status and carbon sequestration capacity due to the inability to detect multiple parameters synchronously.

[0017] (2) This invention discloses a remote sensing imaging system for synchronous monitoring of vegetation composite parameters. All optical paths adopt a reflection system design to eliminate spectral imaging color difference and are suitable for frame structure, realizing the lightweighting of the optomechanical system. All optical components adopt a heatless design, which improves the system stability. The above optical design solves the problems of large aberrations and spectral distortion in large field-of-view spectral detection and low quantitative accuracy of spectral detection.

[0018] (3) This invention discloses a vegetation composite parameter synchronous monitoring remote sensing imaging system. It uses a field-of-view scanning component to realize field-of-view modulation during the push-broom imaging process, which improves the spatial resolution of the system and keeps the system field of view unchanged. It solves the problem of the difficulty in improving the spatial resolution of spectral detection and the contradiction between high spatial resolution and large field of view imaging.

[0019] (4) This invention discloses a remote sensing imaging system for simultaneous monitoring of vegetation composite parameters. The low-distortion, high-dispersion spectral system adopts a small F-number Littrow-Offner configuration to achieve low-distortion hyperspectral resolution spectral dispersion, meeting the requirements of SIF detection for signal-to-noise ratio, spectral resolution, and wavelength accuracy. It solves the problem of weak high spatial resolution SIF signals and the difficulty of satellite remote sensing detection. Attached Figure Description

[0020] Figure 1 This is a block diagram of a remote sensing imaging system for synchronous monitoring of vegetation composite parameters in an embodiment of the present invention.

[0021] Figure 2 This is an optical design diagram of a low-distortion, high-resolution beam splitting system according to an embodiment of the present invention;

[0022] Figure 3 This is an optical design diagram of a low-distortion, high-dispersion beam splitting system according to an embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of the structure of a field-of-view scanning component in an embodiment of the present invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments disclosed in the present invention will be described in further detail below with reference to the accompanying drawings.

[0025] Reference Figure 1In this embodiment, the vegetation composite parameter synchronous monitoring remote sensing imaging system includes: an off-axis three-mirror telescope system 1, a field-of-view scanning component 2, a field-of-view segmentation element 3, a relay optical system 4, a low-distortion high-dispersion beam splitting system 5, a low-distortion high-resolution beam splitting system 6, a first detector focal plane circuit assembly, a second detector focal plane circuit assembly, and an integrated electronics assembly. The relay optical system, the low-distortion high-dispersion beam splitting system 5, and the first detector focal plane circuit assembly constitute a fluorescence detection channel; the low-distortion high-resolution beam splitting system 6 and the second detector focal plane circuit assembly constitute a visible light near-infrared channel. In this system, the incident parallel light is imaged by the off-axis three-reflector telescope system 1, reflected by the field-of-view scanning component 2, and split into two fields of view by the field-of-view splitting element 3. One field of view is imaged to the slit A11 of the low-distortion high-dispersion beam splitting system 5 after passing through the relay optical system 4. After being split by the low-distortion high-dispersion beam splitting system 5, it is imaged onto the detector focal plane of the first detector focal plane circuit component. The other field of view is imaged to the slit B7 of the low-distortion high-resolution beam splitting system 6. After being split by the low-distortion high-resolution beam splitting system 6, it is imaged onto the detector focal plane of the second detector focal plane circuit component. Finally, the integrated electronics components drive the first detector focal plane circuit component and the second detector focal plane circuit component to perform photoelectric signal conversion, complete the hyperspectral and superspectral imaging detection, and realize the remote sensing imaging of simultaneous monitoring of vegetation composite parameters.

[0026] In this embodiment, the off-axis three-mirror telescope system 1 is used to image the radiation received by the entrance pupil of the spectrometer, after passing through the field-of-view scanning component 2 and the field-of-view splitting element 3, onto the slits of the low-distortion high-dispersion beam splitting system 5 and the low-distortion high-resolution beam splitting system 6, respectively. The focal length of the off-axis three-mirror telescope system 1 is designed based on the spatial resolution of the visible and near-infrared channels, and a frame structure is used to support and achieve a lightweight design for the entire system.

[0027] In this embodiment, the field-of-view scanning component 2 is used to fold the optical path and adjust the optical axis in front of the image of the off-axis three-mirror telescope system 1, thereby achieving super-resolution spectral imaging through field-of-view scanning. Wherein, as... Figure 4 As shown, the field-of-view scanning assembly 2 mainly includes: a reflector 15, a piezoelectric two-dimensional scanning mechanism 16, and a scanning control mechanism 17. During push-broom imaging, the piezoelectric two-dimensional scanning mechanism drives the reflector to adjust the optical axis, achieving a sub-pixel shift of 1 / n pixels, combined with n... 2 The frame rate is increased by a factor of n, achieving n times super-resolution detection and relative radiometric correction. Specifically: during imaging, a two-dimensional field of view is scanned along the satellite's orbit and across its orbit; during the scan, n... 2The system employs frame-rate encrypted sampling and pixel-level reciprocating scanning, with sub-pixel offset scanning of 1 / n pixels in the track crossing direction. For the spatial encrypted sampled spectral image obtained by push-broom, a probability density function is constructed using a two-dimensional transfer function and oversampling scenario to solve for the super-resolution image, thereby achieving spatial super-resolution and relative radiometric correction.

[0028] In this embodiment, the field-of-view segmentation element 3 is used to divide the emitted light of the field-of-view scanning component 2 into two fields of view in front of the image of the off-axis three-mirror telescope system 1, which are respectively refracted to the fluorescence detection channel and the visible light near-infrared channel.

[0029] In this embodiment, the relay optical system 4 is used to convert the focal length of the off-axis three-mirror telescope system 1 to a focal length that matches the fluorescence hyperspectral imaging. Specifically, the relay optical system 4 employs an off-axis three-mirror configuration, and by matching it with the off-axis three-mirror telescope system 1, it adjusts the focal length of the fluorescence detection channel to... Among them, the spatial resolution of the fluorescence detection channel is k times that of the visible and near-infrared channel, f represents the focal length of the off-axis three-mirror telescope system 1, and the pixel spacing of the focal plane circuit assembly of the first detector is m times that of the pixel spacing of the focal plane circuit assembly of the second detector.

[0030] In this embodiment, the low-distortion, high-dispersion beam splitting system 5 is used to perform hyperspectral resolution beam splitting on one of the fields of view of the image plane of the off-axis three-mirror telescope system 1, and to image on the detector focal plane of the first detector focal plane circuit assembly. The low-distortion, high-dispersion beam splitting system 5 employs, as follows: Figure 3 The Littrow-Offner spectrometer shown includes a prism grating A13 and a spherical mirror A14. After passing through the slit A11, light passes through the transmission region of the prism grating A13, is reflected by the spherical mirror A14, undergoes dispersion in the grating region of the prism grating A13, is reflected again by the spherical mirror A14, and the aberration is corrected by the transmission region of the prism grating A13, ultimately forming an image on the detector focal plane A12 of the first detector focal plane circuit assembly. Furthermore, a high-line-density convex blazed grating is used on the prism grating A13 to achieve a high dispersion coefficient, meeting the hyperspectral resolution detection requirements of a spectral range of 0.67 μm to 0.78 μm and a spectral resolution of 0.3 nm.

[0031] In this embodiment, the low-distortion high-resolution beam splitting system 6 is used to perform high spatial resolution beam splitting on another field of view of the image plane of the off-axis three-mirror telescope system 1, and to image on the detector focal plane of the second detector focal plane circuit assembly.

[0032] The low-distortion, high-resolution beam splitting system 6 employs, for example... Figure 2The Offner-Wynne spectrometer shown achieves high-resolution, large-field-of-view spectral imaging with a spectral resolution of 10 nm in the 0.45 μm–0.9 μm spectral range. The low-distortion, high-resolution spectrometer system 6 mainly comprises: a prism grating B8 and a spherical mirror B9;

[0033] The system consists of slit B7 and a sphere center. After passing through slit A7, prism grating A8 and spherical reflector A9, light is imaged onto the detector focal plane B10 of the second detector focal plane circuit assembly.

[0034] In this embodiment, the first detector focal plane circuit assembly is used to perform spectral imaging of the fluorescence detection channel on the image plane of the low-distortion high-dispersion spectral system 5.

[0035] In this embodiment, the second detector focal plane circuit assembly is used to perform spectral imaging of the visible and near-infrared channels on the image plane of the low-distortion high-resolution spectral system 6.

[0036] In this embodiment, integrated electronic components are used to power the field scanning component 2, the first detector focal plane circuit component, and the second detector focal plane circuit component, and to send drive signals to the field scanning component 2, the first detector focal plane circuit component, and the second detector focal plane circuit component.

[0037] In this embodiment, the off-axis three-mirror telescope system 1, the field-of-view scanning component 2, the field-of-view segmentation element 3, the relay optical system 4, the low-distortion high-dispersion beam splitting system 5, and the low-distortion high-resolution beam splitting system 6 all adopt the form of reflection. The optical materials and optomechanical structure materials are selected according to the coefficient of thermal expansion. The optomechanical structure adopts a calorimetric design to improve the stability of the system.

[0038] In summary, this invention designs a remote sensing imaging system for simultaneous monitoring of vegetation composite parameters from multiple aspects, including the overall architecture of the remote sensing imaging system, the field-of-view scanning components, and the optical design of the spectral system. The visible and near-infrared channels and the fluorescence detection channel share an off-axis three-mirror telescope system; a thermal-free design of the reflective optical path is adopted to achieve highly stable chromatic aberration-free imaging; n-fold spatial dimension super-resolution and relative radiometric correction are achieved through field-of-view scanning; and Offner spectral analysis is used to achieve large field-of-view, low-distortion spectral detection.

[0039] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

[0040] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A remote sensing imaging system for simultaneous monitoring of vegetation composite parameters, characterized in that, include: The off-axis three-mirror telescope system (1), field-of-view scanning assembly (2), field-of-view splitting element (3), relay optics system (4), low-distortion high-dispersion beam splitting system (5), low-distortion high-resolution beam splitting system (6), first detector focal plane circuit assembly, second detector focal plane circuit assembly, and integrated electronics assembly; the relay optics system (4), low-distortion high-dispersion beam splitting system (5), and first detector focal plane circuit assembly constitute a fluorescence detection channel; the low-distortion high-resolution beam splitting system (6) and second detector focal plane circuit assembly constitute a visible light near-infrared channel; wherein, the incident parallel light is imaged by the off-axis three-mirror telescope system (1), reflected by the field-of-view scanning assembly (2), and split into front and rear beams by the field-of-view splitting element (3). The two fields of view are: one field of view is imaged to the slit A (11) of the low-distortion high-dispersion beam splitting system (5) after passing through the relay optical system (4), and then imaged onto the detector focal plane of the first detector focal plane circuit assembly after being split by the low-distortion high-dispersion beam splitting system (5); the other field of view is imaged to the slit B (7) of the low-distortion high-resolution beam splitting system (6), and then imaged onto the detector focal plane of the second detector focal plane circuit assembly after being split by the low-distortion high-resolution beam splitting system (6); finally, the integrated electronics components drive the first detector focal plane circuit assembly and the second detector focal plane circuit assembly to perform photoelectric signal conversion, complete the hyperspectral and hyperspectral imaging detection, and realize the synchronous monitoring of vegetation composite parameters remote sensing imaging. The field-of-view scanning assembly (2) includes: a reflector (15), a piezoelectric two-dimensional scanning mechanism (16), and a scanning control mechanism (17); during push-broom imaging, the reflector (15) is driven by the piezoelectric two-dimensional scanning mechanism (16) to adjust the optical axis, achieving 1 / n Sub-pixel offset of a pixel, combined n 2 Double the frame rate, achieving n Super-resolution detection and relative radiometric correction; The relay optical system (4) adopts an off-axis three-mirror configuration. By matching it with the off-axis three-mirror telescope system (1), the focal length of the fluorescence detection channel is adjusted to... Among them, the spatial resolution of the fluorescence detection channel is [amount missing] times that of the visible and near-infrared channels. k times, f The focal length of the off-axis three-reflector telescope system (1) is represented by the pixel spacing of the first detector focal plane circuit assembly being equal to the pixel spacing of the second detector focal plane circuit assembly. m times; The low-distortion, high-dispersion beam splitting system (5) includes: a prism grating A (13) and a spherical mirror A (14); after passing through the slit A1 (11), the light passes through the transmission area of ​​the prism grating A (13), is reflected by the spherical mirror A (14), is dispersed by the grating area of ​​the prism grating A (13), is reflected again by the spherical mirror A (14), and the aberration is corrected by the transmission area of ​​the prism grating A (13), and finally imaged on the detector focal plane A (12) of the first detector focal plane circuit assembly; The low-distortion high-resolution beam splitting system (6) includes a prism grating B (8) and a spherical mirror B (9); after passing through the slit B (7), the prism grating B (8) and the spherical mirror B (9), the light is imaged on the detector focal plane B (10) of the second detector focal plane circuit assembly.

2. The vegetation composite parameter synchronous monitoring remote sensing imaging system according to claim 1, characterized in that, The off-axis three-reflector telescope system (1) is used to image the radiation received by the entrance pupil of the spectrometer onto the slits of the low-distortion high-dispersion spectral system (5) and the low-distortion high-resolution spectral system (6) after passing through the field scanning component (2) and the field splitting element (3).

3. The vegetation composite parameter synchronous monitoring remote sensing imaging system according to claim 1, characterized in that, The field-of-view scanning component (2) is used to fold the optical path and adjust the optical axis in front of the image of the off-axis three-mirror telescope system (1) to achieve super-resolution spectral imaging through field-of-view scanning.

4. The vegetation composite parameter synchronous monitoring remote sensing imaging system according to claim 1, characterized in that, The field-of-view splitting element (3) is used to split the outgoing light of the field-of-view scanning component (2) into two fields of view in front of the image of the off-axis three-reflector telescope system (1), which are then refracted to the fluorescence detection channel and the visible light near-infrared channel, respectively.

5. The vegetation composite parameter synchronous monitoring remote sensing imaging system according to claim 1, characterized in that, A relay optical system (4) is used to convert the focal length of the off-axis three-reflector telescope system (1) to a focal length that matches the fluorescence hyperspectral imaging.

6. The vegetation composite parameter synchronous monitoring remote sensing imaging system according to claim 1, characterized in that, The low-distortion, high-dispersion beam splitting system (5) is used to perform hyperspectral resolution beam splitting on one of the fields of view of the image plane of the off-axis three-reflector telescope system (1) and to image on the detector focal plane of the first detector focal plane circuit assembly.

7. The vegetation composite parameter synchronous monitoring remote sensing imaging system according to claim 1, characterized in that, A low-distortion, high-resolution beam splitting system (6) is used to perform high spatial resolution beam splitting on another field of view of the image plane of the off-axis three-reflector telescope system (1) and to image on the detector focal plane of the second detector focal plane circuit assembly.

8. The vegetation composite parameter synchronous monitoring remote sensing imaging system according to claim 1, characterized in that, The first detector focal plane circuit assembly is used to perform spectral imaging of the fluorescence detection channel on the image plane of the low-distortion high-dispersion spectral system (5).

9. The vegetation composite parameter synchronous monitoring remote sensing imaging system according to claim 2, characterized in that, The second detector focal plane circuit assembly is used to perform spectral imaging of the visible and near-infrared channels on the image plane of the low-distortion high-resolution spectral system (6).

10. The vegetation composite parameter synchronous monitoring remote sensing imaging system according to claim 1, characterized in that, The integrated electronics component supplies power to the field scanning component (2), the first detector focal plane circuit component, and the second detector focal plane circuit component, and sends drive signals to the field scanning component (2), the first detector focal plane circuit component, and the second detector focal plane circuit component.

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