CN-121977693-A - Picture frame type image space scanning hyperspectral imaging system

CN121977693ACN 121977693 ACN121977693 ACN 121977693ACN-121977693-A

Abstract

The invention discloses a frame-type image space scanning hyperspectral imaging system, and belongs to the technical field of remote sensing imaging. The system comprises a telescope system, an image space scanning combined mirror, a slit protection assembly, a spectrometer and a detector. The image space scanning combined mirror consists of a first reflecting mirror and a second reflecting mirror, wherein the reflecting surfaces of the image space scanning combined mirror are in a V shape with an included angle of 90 degrees, and the included angles of the image space scanning combined mirror and the optical axis are 45 degrees. The combined mirror is used as the only moving part in the system, and moves linearly back and forth along the direction perpendicular to the optical axis, the two-dimensional picture formed by the telescope system is pushed into the slit in sequence, and is received by the detector after being split by the spectrometer, so that picture hyperspectral imaging of a rectangular area of an object is realized. The invention can complete scanning by only single component movement, has simple and compact structure, remarkably reduces the dependence on satellite platform control precision and resources, is suitable for various telescope configurations, and provides a reliable solution for large-caliber hyperspectral imaging load.

Inventors

ZHANG ZONGCUN
CUI CANCAN
LIU YINNIAN
CHAI MENGYANG
CAO KAIQIN
JIA XIAOWEI
LIU GUOQING
JI CHENGSHENG
ZHAO YUN
LI XUN

Assignees

中国科学院上海技术物理研究所

Dates

Publication Date: 20260505
Application Date: 20260113

Claims (10)

1. The image scanning hyperspectral imaging system is characterized by comprising a telescope system (1), an image scanning combined mirror (2), a slit protection assembly (3), a spectrometer (4) and a detector (5), wherein: The image space scanning combined mirror (2) comprises a first reflecting mirror (2-1) and a second reflecting mirror (2-2), wherein the reflecting surfaces of the first reflecting mirror (2-1) and the second reflecting mirror (2-2) form a V shape with an included angle of 90 degrees, and the included angles of the reflecting surfaces and an optical axis (0) are 45 degrees; Different view field light generated by a rectangular area target from the ground surface is converged by a telescope system (1) to form a two-dimensional image, then the two-dimensional image is irradiated to an image space scanning combined mirror (2), the two-dimensional image formed by the telescope system (1) at different positions sequentially enters a spectrometer (4) through a slit protection assembly (3) to carry out synchronous spectrum spectroscopic imaging through the back and forth movement of the image space scanning combined mirror (2) along the direction perpendicular to an optical axis (0) of the telescope system, and finally the two-dimensional image is received by a detector (5) to finish the image space scanning imaging of an object space.
2. The frame-type image scanning hyperspectral imaging system according to claim 1, wherein the slit protection component (3) comprises an upper slit protection sheet (3-1), a slit (3-2), a lower slit protection sheet (3-3) and a light turning mirror (3-4), after a two-dimensional frame image formed by the telescope system (1) at different positions passes through the image scanning combined mirror (2) at the image side, the two-dimensional frame image sequentially passes through the upper slit protection sheet (3-1) to reach the position of an image surface (6) of the telescope system (1), and then light is blocked by the slit (3-2) to obtain an image with only one pixel-level narrow line view field, and light formed by the image continues to enter the spectrometer (4) through the lower slit protection sheet (3-3) and the light turning mirror (3-4).
3. A frame-type image scanning hyperspectral imaging system as claimed in claim 1 wherein the first mirror (2-1) and the second mirror (2-2) are two triangular mirror bodies separated from each other, the reflecting surfaces of which are located on the outer surface of the transmissive material where the long sides of the triangles are located, and both face the direction of the incident light.
4. A frame-type image-side scanning hyperspectral imaging system as claimed in claim 1, wherein the first reflecting mirror (2-1) and the second reflecting mirror (2-2) are rectangular integrated mirrors with V-shaped grooves, and the reflecting surfaces are positioned on the outer surfaces of the transmission materials on both sides of the V-shaped grooves and face the incident light direction.
5. A frame-type image-side scanning hyperspectral imaging system as claimed in claim 1, wherein the first reflecting mirror (2-1) and the second reflecting mirror (2-2) are closed polygonal integrated mirrors with V-shaped protrusions, and the reflecting surfaces are positioned on the inner surfaces of the transmissive materials on both sides of the V-shaped ribs and face the incident light direction.
6. A frame-type image-side scanning hyperspectral imaging system as claimed in claim 1, wherein the telescope system (1) is an image-side telecentric telescope system, and the angle between the principal ray (7) of the edge view field and the optical axis (0) of the telescope system is 0 ° -2 °.
7. A frame-type image-side scanning hyperspectral imaging system as claimed in claim 1, wherein the image-side scanning combined mirror (2) is driven by a high-precision control motor (8) to perform linear uniform motion along the direction perpendicular to the optical axis (0) of the telescope system, and the moving precision and the position repetition precision are smaller than the size of 0.1 detection pixels.
8. A frame-wise image scanning hyperspectral imaging system as claimed in claim 1 wherein the ratio between the scanning movement speed of the image-wise scanning combiner mirror (2) and the speed of the image point on the image plane (6) of the telescopic system (1) passing through the centre of the slit (3-2) is 1:2.
9. A frame-wise image-wise scanning hyperspectral imaging system as claimed in claim 1 wherein the detector (5) comprises an area array detector (5-1) for full color imaging, and when the image-wise scanning combiner mirror (2) is moved out of the optical path of the telescopic system (1) completely, wide field of view light from the object is received directly by the area array detector (5-1) for frame-wise full color imaging.
10. The frame-type image scanning hyperspectral imaging system according to claim 1 is characterized in that the detector (5) comprises a multispectral detector (5-2), the image scanning combined mirror (2) moves at a uniform speed along a direction perpendicular to the optical axis (0) of the system, the photosensitive surface of the detector (5) can be guaranteed to coincide with the image surface (6) of the telescope system (1), different fields of view generated by a rectangular surface area target from the ground surface are converged by the telescope system (1) to form a two-dimensional frame image and then irradiated to the image scanning combined mirror (2), the two-dimensional frame image formed by the telescope system (1) at different positions is moved up and down at a non-defocused speed along the direction perpendicular to the optical axis (0) through the image scanning combined mirror (2), and the two-dimensional frame image is sequentially received by the multispectral detector (5-2), and then the frame-type multispectral imaging is realized.

Description

Picture frame type image space scanning hyperspectral imaging system Technical Field The invention belongs to the technical field of remote sensing imaging, and particularly relates to a frame-type image space scanning hyperspectral imaging system. Background The hyperspectral imaging technology can simultaneously acquire two-dimensional space information and one-dimensional spectrum information of a target, and has outstanding effects in the fields of remote sensing to the earth, environmental monitoring and the like. The dispersive spectroscopic hyperspectral imaging technology is widely applied because of high data purity and strong direct readability, but the working mode of the line field of view determines that only spectral data on one line can be acquired at a time. To obtain a two-dimensional frame hyperspectral image, a field of view scan along the orbital direction must be achieved. The prior art mainly relies on two scanning modes, namely object side scanning and image side scanning. The object scanning is usually realized by moving a scanning mirror arranged in front of a telescope, but this has the obvious technical defects that the size of the scanning mirror is equivalent to that of the telescope, so that the system volume, weight and inertia are increased greatly, more importantly, as shown in fig. 1, the object scanning mirror 9 is adopted to scan the ground, the whole envelope weight of the camera is greatly increased, and meanwhile, serious ground imaging distortion is introduced in the scanning process, namely, the imaging resolution is obviously degraded along with the increase of the scanning field angle, so that the image quality of the edge and the center of the picture is inconsistent. The platform push-broom mode is free of distortion, but completely depends on the satellite platform to carry out accurate and uniform flight to realize scanning, and has extremely high requirements on the control precision and stability of the platform, and the data splicing is complex. To overcome the drawbacks of object-side scanning, image-side scanning techniques have been developed. The conventional image space scanning realizes two-dimensional scanning of a line field on an image plane by arranging a single plane scanning mirror 10 near the focal plane of an optical system, and has the advantages of small volume and quick dynamic response. However, during scanning, movement of the single plane scanning mirror 10 inevitably causes the telescope image plane to shift (as shown in fig. 2 (a)) or tilt (as shown in fig. 2 (b)), resulting in out of focus of the image point, severely compromising imaging quality. To solve this defocus problem, the existing solution has to introduce additional moving parts, such as a co-moving focal plane compensation mirror 11 (as disclosed in patent CN 202511192378.0), i.e. as shown in fig. 2 (c), to dynamically compensate the image plane position by the precise co-movement of the multiple parts. The dual-motion part mode of the scanning mirror and the compensation mirror solves the problem of image plane virtual focus in principle, but also leads to complex system structure, complex control logic, increased reliability risk and increased cost, and the system cannot be simplified fundamentally. Therefore, an innovative image space scanning scheme is needed at present, which can thoroughly avoid object space scanning distortion, solve the problem of image space defocus of traditional image space scanning, abandon dependence on an additional compensation component, and realize frame-type hyperspectral imaging with high image quality through simple movement of a single movement component, so that a solution with simple structure, stability, reliability and easy engineering realization is provided for large-caliber and high-resolution spectral imaging load. Disclosure of Invention In order to solve the technical problems, the invention provides a frame-type image scanning hyperspectral imaging system which can be applied to dispersion split type area array staring hyperspectral imaging and area array staring multispectral earth remote sensing imaging detection, and adopts an image scanning method to realize object space frame-type hyperspectral imaging, solve the problem of large increase of the whole envelope weight of a camera caused by an object scanning mirror mode, simultaneously completely avoid ground scanning imaging distortion, and break the bottleneck that the dispersion split type hyperspectral and multispectral load has large resource requirement, high control precision and high dependence on a satellite platform. In order to achieve the above purpose, the invention adopts the following technical scheme: a frame-type image-side scanning hyperspectral imaging system comprises a telescope system, an image-side scanning combined mirror, a slit protection assembly, a spectrometer and a detector, wherein, The image space scanning combined mirror comprises a first