CN-121994355-A - Wide-spectrum-section common-caliber hyperspectral imaging device and method

CN121994355ACN 121994355 ACN121994355 ACN 121994355ACN-121994355-A

Abstract

The invention discloses a wide-spectrum co-aperture hyperspectral imaging device and a method, and belongs to the technical field of spectral imaging. The device comprises a collimation system (1), a color separation film (2), a visible near infrared band light splitting element (3), a visible near infrared band focusing lens group (4), a visible near infrared band light filter (5), a short wave infrared band light splitting element (6), a short wave infrared band focusing lens group (7) and a short wave infrared band light filter (8). After being collimated by the collimation system (1), the light beam is divided into a visible near infrared path and a short wave infrared path by the color separation film (2), is split by the visible near infrared band splitting element (3) combined by the transmission grating and the prism and the short wave infrared band splitting element (6) of the reflection grating, and is converged to the corresponding image surface by the respective focusing lens groups (4, 7). The invention realizes the synchronous acquisition of the linear dispersion hyperspectral in the ultra-wide band of 400-2500 nm.

Inventors

JING JUANJUAN
LI MINGFEI
ZHOU JINSONG
NIE BOYANG
YANG LEI

Assignees

中国科学院空天信息创新研究院

Dates

Publication Date: 20260508
Application Date: 20260122

Claims (10)

1. A wide-spectrum common-caliber hyperspectral imaging device is characterized by comprising a collimation system, a color separation piece, a visible near-infrared band light splitting element, a visible near-infrared band focusing lens group, a visible near-infrared band light splitting element, a short-wave infrared band focusing lens group and a short-wave infrared band light splitting element, wherein the collimation system consists of a slit, a plane mirror and a spherical collimation mirror, the slit is arranged in a joint mode with the plane mirror, a rectangular hole is formed in the middle of the plane mirror, a light beam emitted from the slit passes through the rectangular hole and reaches the spherical collimation mirror to be collimated and then reflected by the plane mirror to enter the color separation piece, the light beam is split into two paths after passing through the color separation piece, the visible near-infrared band light beam is reflected by the color separation piece to enter a visible near-infrared band light splitting element to be split, then converged by the visible near-infrared band focusing lens group, the short-wave band light beam passes through the color separation piece to be split by the visible near-infrared band light splitting element, then converged by the infrared band focusing lens group, and then passes through the short-wave infrared band light splitting element to reach the infrared image plane.
2. The broad spectrum common aperture hyperspectral imaging apparatus as claimed in claim 1 wherein the visible near infrared band spectroscopic element is comprised of a transmission grating and a prism, the prism being disposed behind the transmission grating.
3. The broad spectrum band co-aperture hyperspectral imaging apparatus as claimed in claim 1 or claim 2 wherein the short wave infrared band spectroscopic element comprises a reflection grating arranged at an angle to the optical axis direction to correct spherical aberration, spectral line bending and colour distortion by automatic optimisation.
4. The broad spectrum common aperture hyperspectral imaging apparatus of claim 1 wherein the visible near infrared band focusing lens group and the short wave infrared band focusing lens group are both composed of spherical lenses.
5. The wide-band co-aperture hyperspectral imaging device of claim 1, wherein the visible near infrared band filter is coated with a long-wavelength cut-off filter film near the surface of the visible near infrared image plane, and the short-wavelength cut-off wavelength is 550nm.
6. The broad band common-caliber hyperspectral imaging device of claim 1, wherein the ratio of the focal length of the visible near infrared band focusing lens group to the focal length of the collimating system achieves a zoom ratio of 0.733, and the ratio of the focal length of the short wave infrared band focusing lens group to the focal length of the collimating system achieves a zoom ratio of 1.
7. The wide-band co-aperture hyperspectral imaging apparatus of claim 2 wherein the angle of the transmission grating with respect to the optical axis and the apex angle of the prism are determined by the spectral dimension length on the image plane, the grating line pair number and the focal length of the visible near infrared band focusing lens group, and the air gap between the prism and the grating is increased to cancel out the line bending and the color distortion caused by the prism and the grating.
8. The broad spectrum common aperture hyperspectral imaging apparatus as claimed in claim 4, wherein the visible near infrared band splitting element and the visible near infrared band focusing lens group are coaxial in the optical axis direction, and the short wave infrared band splitting element and the short wave infrared band focusing lens form an included angle setting.
9. The broad spectrum common aperture hyperspectral imaging apparatus as claimed in claim 5, wherein the short wave infrared band filter is coated with a long wave pass cut-off filter film near the surface of the short wave infrared image plane, and the short wave cut-off wavelength is 1300nm.
10. A wide-spectrum common-caliber hyperspectral imaging method is characterized by adopting the wide-spectrum common-caliber hyperspectral imaging device according to any one of claims 1 to 9, and the method comprises the steps that a target light beam enters through a slit, passes through a rectangular hole of a plane reflector, is collimated by a spherical collimating mirror, is folded by the plane reflector and enters a color separation film, the color separation film divides the light beam into a reflected visible near-infrared band light beam and a transmitted short-wave infrared band light beam, the two paths of light beams respectively enter a visible near-infrared band light splitting element and a short-wave infrared band light splitting element, the split light beam passes through a visible near-infrared band focusing mirror group and a short-wave infrared band focusing mirror group, secondary spectrum aliasing is eliminated through a visible near-infrared band light filter and a short-wave infrared band light filter plated with a long-pass cut-off filter film, and finally, the light beam is respectively imaged on a visible near-infrared image surface and a short-wave infrared image surface, and linear dispersion hyperspectral synchronous acquisition of an ultra-wide band of 400-2500nm is realized.

Description

Wide-spectrum-section common-caliber hyperspectral imaging device and method Technical Field The invention belongs to the technical field of spectrum imaging, and particularly relates to a wide-spectrum co-aperture hyperspectral imaging device and method. Background The spectrum imaging technology can synchronously acquire the space geometric characteristics and the spectrum radiation characteristics of the detected target, and has important application value in the fields of resource exploration, environment monitoring, target identification and the like. In order to realize full-spectrum coverage from visible light to short-wave infrared band, the traditional technical route generally adopts a mode of combining and configuring a plurality of discrete optical path systems, so that the whole structure is complex, the mass and the volume are large, and the method is difficult to adapt to a miniaturized air detection platform and an unmanned system which have extremely strict requirements on the load size and the mass. Aiming at the defects, the prior art provides a common-caliber spectrum imaging scheme based on an off-axis reflection type structure, and the scheme realizes the compact design of the system to a certain extent by sharing a front optical system and a broadband detector. However, the off-axis structure based on the prism dispersion principle still has the technical bottlenecks that firstly, the envelope size and the quality of an optical system still exceed the bearing capacity of a miniaturized platform obviously, and secondly, the inherent nonlinear spectrum broadening characteristic of the prism dispersion causes spectrum distortion, so that the complexity of subsequent spectrum calibration and radiation processing is increased, and the accuracy of quantization application is restricted. Therefore, the existing off-axis reflection type common-caliber spectrum imaging device has the defects of miniaturization and light weight, and the nonlinear dispersion effect introduced by the prism light splitting element influences the accuracy of spectrum data processing, and the conventional grating-prism hybrid spectrum imager is difficult to realize full-spectrum response coverage from visible light to short-wave infrared wave bands under a single equipment architecture. Disclosure of Invention In order to solve the technical problems, the invention provides the wide-spectrum co-caliber hyperspectral imaging device and the wide-spectrum co-caliber hyperspectral imaging method, which can meet the constraint requirements of geometric dimension, quality and cost while realizing the detection capability of visible light to short-wave infrared wide-spectrum, maintain the linear sampling characteristic of spectrum dimension and improve the convenience and precision of remote sensing data processing. In order to achieve the above purpose, the invention adopts the following technical scheme: The wide-spectrum common-caliber hyperspectral imaging device comprises a collimation system, a color separation film, a visible near-infrared band light splitting element, a visible near-infrared band focusing lens group, a visible near-infrared band light filter, a short-wave infrared band light splitting element, a short-wave infrared band focusing lens group and a short-wave infrared band light filter, wherein the collimation system consists of a slit, a plane mirror and a spherical collimation mirror, the slit is arranged in a bonding mode with the plane mirror, a rectangular hole is formed in the middle of the plane mirror, a light beam emitted from the slit passes through the rectangular hole to reach the spherical collimation mirror for collimation, then is reflected by the plane mirror to enter the color separation film, the light beam is split into two paths after passing through the color separation film, the visible near-infrared band light beam is reflected by the color separation film to enter the visible near-infrared band light splitting element for light splitting, then is converged by the visible near-infrared band focusing lens group, the short-wave band light beam passes through the short-wave band light splitting element for light splitting, then is converged by the short-wave infrared band light focusing lens group, and then passes through the infrared band light focusing lens group for short-wave infrared imaging plane. Further, the visible near infrared band light splitting element is composed of a transmission grating and a prism, and the prism is arranged behind the transmission grating. Further, the short-wave infrared band light splitting element comprises a reflection grating, the reflection grating and the optical axis direction form an included angle, and spherical aberration, spectral line bending and color distortion are automatically optimized and corrected. Further, the visible near infrared band focusing lens group and the short wave infrared band focusing lens group are both composed