An airborne snapshot hyperspectral polarization zoom imaging optical system

Abstract

The present application discloses an airborne snapshot hyperspectral polarization zoom imaging optical system, which relates to the field of optical technology. The airborne snapshot hyperspectral polarization zoom imaging optical system comprises a front zoom telescope group, a digital micromirror arranged on an outgoing light path of the front zoom telescope group, a relay lens group arranged on an outgoing light path of the digital micromirror, a prism-grating-prism arranged on an outgoing light path of the relay lens group, an imaging lens group arranged on an outgoing light path of the prism-grating-prism, and a polarization detector arranged on an outgoing light path of the imaging lens group; the front zoom telescope group comprises a front fixed group, a zoom group, a rear compensation group, an aperture, and a rear fixed group arranged in sequence from the object side to the image side; the zoom group slides between the front fixed group and the rear compensation group to achieve zooming. The present application can quickly discover targets and perform fine identification of targets.

Description

Technical Field

[0001] The present application relates to the field of optical technology, and in particular to an airborne snapshot hyperspectral polarization zoom imaging optical system. Background Art

[0002] Existing airborne spectral polarization imaging optical systems mostly use fixed-focus systems, which results in the inability to achieve both high spatial resolution and high spectral resolution at the same time. While improving the spectral resolution, the spatial resolution of the fixed-focus spectral polarization imaging system is limited, making it difficult to identify the target in a refined manner. By adopting a zoom system, the spatial resolution can be improved in the telephoto state, but the push-broom spectral polarization imaging mechanism cannot achieve rapid zooming, resulting in the inability to quickly detect the target. Based on this, an airborne polarization spectral imaging optical system is needed that can quickly detect the target and perform refined identification of the target. Summary of the invention

[0003] The purpose of this application is to provide an airborne snapshot hyperspectral polarization zoom imaging optical system that can quickly detect targets and perform fine identification of targets.

[0004] To achieve the above objectives, this application provides the following solutions:

[0005] In a first aspect, the present application provides an airborne snapshot hyperspectral polarization zoom imaging optical system, comprising:

[0006] A front zoom telescope group, a digital micromirror arranged on an outgoing light path of the front zoom telescope group, a relay lens group arranged on an outgoing light path of the digital micromirror, a prism-grating-prism arranged on an outgoing light path of the relay lens group, an imaging lens group arranged on an outgoing light path of the prism-grating-prism, and a polarization detector arranged on an outgoing light path of the imaging lens group;

[0007] The front zoom telescope group includes a front fixed group, a variable magnification group, a rear compensation group, an aperture and a rear fixed group which are arranged in sequence from the object side to the image side; the variable magnification group slides between the front fixed group and the rear compensation group to achieve zooming.

[0008] Optionally, the front fixed group has positive refractive power, the variable power group has negative refractive power, the rear compensation group has negative refractive power, and the rear fixed group has positive refractive power.

[0009] Optionally, the relay mirror group includes: a first transmission mirror with positive refractive power, a second transmission mirror with negative refractive power, a third transmission mirror with positive refractive power, a fourth transmission mirror with positive refractive power, a fifth transmission mirror with positive refractive power, a sixth transmission mirror with negative refractive power and a seventh transmission mirror with positive refractive power, which are arranged in sequence from the object side to the image side.

[0010] Optionally, the imaging lens group includes: an eighth transmission mirror with positive refractive power, a double-cemented transmission mirror with positive refractive power, a ninth transmission mirror with negative refractive power, a tenth transmission mirror with positive refractive power, and an eleventh transmission mirror with positive refractive power, which are arranged in sequence from the object side to the image side.

[0011] Optionally, the front zoom telescope group is an image-side telecentric structure.

[0012] Optionally, the relay lens assembly is an object-side telecentric structure.

[0013] Optionally, the digital micromirror is a spatial light modulator.

[0014] Optionally, the back focus distance of the front zoom telescope group is 100 mm.

[0015] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0016] The present application provides an airborne snapshot hyperspectral polarization zoom imaging optical system, wherein a front zoom telescope group comprises a front fixed group, a zoom group, a rear compensation group, an aperture and a rear fixed group arranged in sequence from the object side to the image side, and the zoom group can slide between the front fixed group and the rear compensation group to achieve zooming, thereby solving the problem that high spatial resolution and high spectral resolution cannot be taken into account at the same time due to the use of a fixed focus system, and achieving the effect of fine identification of the target; by using the snapshot detection principle, the problem of being unable to zoom quickly is solved, and the effect of being able to quickly discover the target is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 A schematic diagram of the structure of an airborne snapshot hyperspectral polarization zoom imaging optical system provided in one embodiment of the present application.

[0019] Figure 2 A two-dimensional diagram of the short-focus state structure of the front zoom telescope group of the airborne snapshot hyperspectral polarization zoom imaging optical system provided in one embodiment of the present application.

[0020] Figure 3 This is a modulation transfer function diagram of the short-focus state of the front zoom telescope group of the airborne snapshot hyperspectral polarization zoom imaging optical system provided in one embodiment of the present application.

[0021] Figure 4A two-dimensional diagram of the telephoto state structure of the front zoom telescope group of the airborne snapshot hyperspectral polarization zoom imaging optical system provided in one embodiment of the present application.

[0022] Figure 5 A modulation transfer function diagram of the telephoto state of the front zoom telescope group of the airborne snapshot hyperspectral polarization zoom imaging optical system provided in one embodiment of the present application.

[0023] Figure 6 A schematic diagram of the digital micromirror structure of an airborne snapshot hyperspectral polarization zoom imaging optical system provided in one embodiment of the present application.

[0024] Figure 7 A schematic diagram of the tilt angle of a single sub-mirror in a digital micromirror of an airborne snapshot hyperspectral polarization zoom imaging optical system provided in one embodiment of the present application.

[0025] Figure 8 A two-dimensional diagram of the relay lens group structure of an airborne snapshot hyperspectral polarization zoom imaging optical system provided in one embodiment of the present application.

[0026] Fig. 9 A modulation transfer function diagram of a relay lens assembly of an airborne snapshot hyperspectral polarization zoom imaging optical system provided in one embodiment of the present application.

[0027] Fig.10 A schematic diagram of the prism-grating-prism structure of an airborne snapshot hyperspectral polarization zoom imaging optical system provided in one embodiment of the present application.

[0028] Fig.11 A two-dimensional diagram of the imaging lens structure of an airborne snapshot hyperspectral polarization zoom imaging optical system provided in one embodiment of the present application.

[0029] Fig.12 This is a modulation transfer function diagram of the imaging lens group of the airborne snapshot hyperspectral polarization zoom imaging optical system provided in one embodiment of the present application at a central wavelength of 500nm.

[0030] Fig.13 A two-dimensional diagram of the short-focus state structure of an airborne snapshot hyperspectral polarization zoom imaging optical system provided in one embodiment of the present application.

[0031] Fig.14 A two-dimensional diagram of the telephoto state structure of an airborne snapshot hyperspectral polarization zoom imaging optical system provided in one embodiment of the present application.

[0032] Explanation of symbols: front zoom telescope group 100, digital micromirror 200, relay lens group 300, prism-grating-prism 400, imaging lens group 500, polarization detector 600, front fixed group 101, zoom group 102, rear compensation group 103, aperture 104, rear fixed group 105, first transmission mirror 301, second transmission mirror 302, third transmission mirror 303, fourth transmission mirror 304, fifth transmission mirror 305, sixth transmission mirror 306, seventh transmission mirror 307, first prism 401, transmission type volume phase holographic grating 402, second prism 403, eighth transmission mirror 501, double-glued transmission mirror 502, ninth transmission mirror 503, tenth transmission mirror 504, eleventh transmission mirror 505. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0034] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0035] The airborne snapshot hyperspectral polarization zoom imaging optical system provided in the embodiment of the present application is an optical system with a single optical path and a single detector, which can quickly switch between short-focus and long-focus states. Figure 1 As shown, it specifically includes: a front zoom telescope group 100, a digital micromirror 200 arranged on the outgoing light path of the front zoom telescope group 100, a relay lens group 300 arranged on the outgoing light path of the digital micromirror 200, a prism-grating-prism 400 arranged on the outgoing light path of the relay lens group 300, an imaging lens group 500 arranged on the outgoing light path of the prism-grating-prism 400, and a polarization detector 600 arranged on the outgoing light path of the imaging lens group 500. Figure 2 and Figure 4 As shown, the front zoom telescope group 100 includes a front fixed group 101, a variable magnification group 102, a rear compensation group 103, an aperture 104 and a rear fixed group 105 arranged in sequence from the object side to the image side; the variable magnification group 102 slides between the front fixed group 101 and the rear compensation group 103 for simultaneous zooming and focusing, and can achieve short-focus and long-focus two-speed zooming, such as Fig.13 and Fig.14 shown.

[0036] The propagation process of the light emitted by the object to be measured in the airborne snapshot hyperspectral polarization zoom imaging optical system provided in the embodiment of the present application is as follows: the front zoom telescope group 100 makes the light emitted by the object to be measured converge and form an image at the digital micromirror 200, the digital micromirror 200 encodes and modulates the primary image plane formed by the zoom telescope group and then reflects it to enter the relay lens group 300, the relay lens group 300 receives the reflected light after encoding and modulating by the digital micromirror 200 and emits collimated parallel light to enter the prism-grating-prism 400, the prism-grating-prism 400 is used to split the light emitted by the object to be measured, the imaging lens group 500 converges the diffracted light emitted by the prism-grating-prism 400 to form an image on the polarization detector 600, and the polarization detector 600 is used to receive system imaging and obtain the spectrum and polarization information of the object to be measured.

[0037] In practical applications, the front fixing group 101 has positive refractive power, the variable power group 102 has negative refractive power, the rear compensation group 103 has negative refractive power, and the rear fixing group 105 has positive refractive power.

[0038] In practical applications, the signal-to-noise ratio (SNR) of an imaging spectrometer using the zoom imaging optical system provided by the present application is as follows: (1)

[0039] in, and represents the length and width of the polarization detector 600 pixels, represents the transmittance of the zoom imaging optical system, represents the reflectivity of the digital micromirror 200, Indicates the energy utilization rate of the spectroscopic element, represents the quantum efficiency of the polarization detector 600, represents the integration time, represents the spectrum sampling rate, represents the spectrum sampling interval, represents the wavelength of light, F represents the F / # of the optical system, is Planck's constant, is the speed of light in vacuum, represents the readout noise of the polarization detector 600. Under the above conditions, the signal-to-noise ratio is mainly related to the reflectivity of the digital micromirror 200. related.

[0040] In practical applications, such as Figure 6 and Figure 7 As shown, the reflectivity function of the digital micromirror 200 is as follows

[0041] (2)

[0042] in, Figure 6 middle, The axis is the length direction of the digital micromirror 200, The axis is the width direction of the digital micromirror 200, Indicates the length direction of the digital micromirror 200 ( ) length, Indicates the width direction of the digital micromirror 200 ( ), Figure 7 In the equation, N represents the normal of the reflecting surface. Represents the mirror normal and The angle of the plane, Represents the mirror normal and The angle of the plane, represents the length direction variable of the digital micromirror 200, represents the width direction variable of the digital micromirror 200, rect() is the rectangular pulse function, exp is the natural exponential function, i is the imaginary unit, is the diagonal length of the sub-micromirror, is the sub-micromirror tilt angle, is the wavelength of incident light, is the incident angle of the sub-micromirror in the “on” state, is the reflectivity of the material of the digital micromirror 200.

[0043] For digital micromirrors 200 of the same size, larger sub-micromirror sizes and larger material reflectivity can both improve the reflectivity of the digital micromirror 200, but larger sub-micromirrors mean fewer sub-micromirrors, which will affect the modulation of the optical signal. Preferably, the Texas Instruments V-6501VIS model digital micromirror 200 is selected, with a resolution of 1920×1080, a pixel size of 7.6um, an image plane size of 16.7mm, and a half-image height of 8.35mm. In order to improve the utilization rate of the coding area of ​​the digital micromirror 200 and increase the light transmission energy of the system, the front zoom telescope group 100 is required to have a large image plane capability, and the image plane completely covers the target surface of the digital micromirror 200.

[0044] In practical applications, due to the reflection of the light path by the digital micromirror 200 and the requirement of the prism-grating-prism 400 for the incident collimated parallel light of the light path, in order to simplify the structure and reduce the adjustment error, the front zoom telescope group 100 needs to only change the focal length of the system in the short-focus state and the long-focus state without changing the subsequent light path. Therefore, the aperture angle of each field of view 1 at the primary image plane digital micromirror 200 needs to be consistent in the two states. In this application, in order to achieve the above requirements, in the two focal length states, the F / # remains unchanged, the position and size of the aperture 104 remain unchanged, and only the position of the zoom group 102 is changed, which can satisfy the overall system to only change the focal length, and there is no need for the subsequent system to add movable structural parts to match the light paths of different focal length states. The focal length is normalized to 1 in the short-focus state. The optical system structural parameters of the front zoom telescope group 100 are shown in Table 1.

[0045] Table 1 Optical structure parameters

[0046]

[0047] The technical specifications of the front zoom telescope set 100 are:

[0048] In short-focus mode, focal length: 40mm, entrance pupil diameter: 8.9mm, field of view: 23.76°, F / #: 4.5, operating wavelength: 400-650nm. Figure 3 As shown, the MTF of the front zoom telescope set 100 in the short-focus state at the Nyquist frequency of 66lp / mm is above 0.4.

[0049] Telephoto state, focal length: 120mm, entrance pupil diameter: 26.7mm, field of view: 8.03°, F / #: 4.5, working band: 400-650nm; Figure 5 The MTF of the front zoom telescope set 100 in the telephoto state at the Nyquist frequency of 66lp / mm is above 0.5.

[0050] In practical applications, the front telescope group needs to be spliced ​​with the subsequent optical system, so the front zoom telescope group 100 is an image-side telecentric structure, and the incident angle of the main light of each field of view at the image plane should be close to .

[0051] Since the system uses the digital micromirror 200 as a primary image plane to encode and modulate the target optical signal, the characteristic of the digital micromirror 200 is that the light transmitted from the front optical system is reflected at an angle of 24° into the subsequent optical system. Therefore, the front zoom telescope group 100 needs to have a long back focus to avoid interference with the subsequent optical system. Therefore, in practical applications, the back focus of the front zoom telescope group 100 is 100 mm.

[0052] In practical applications, the digital micromirror 200 is a spatial light modulator, which is used to encode and modulate the light emitted by the object under test and reflect it into a subsequent optical system.

[0053] In practical applications, such as Figure 8As shown, the relay lens assembly 300 includes: a first transmission mirror 301 with positive refractive power, a second transmission mirror 302 with negative refractive power, a third transmission mirror 303 with positive refractive power, a fourth transmission mirror 304 with positive refractive power, a fifth transmission mirror 305 with positive refractive power, a sixth transmission mirror 306 with negative refractive power and a seventh transmission mirror 307 with positive refractive power, which are arranged in sequence from the object side to the image side. The parallel light output aperture of the relay lens group 300 should consider both the splitting ability of the optical system and the overall light transmission energy of the optical system. The selected prism-grating-prism 400 has an aperture of 25 mm. Since the splitting ability at the center of the grating is stronger than that at the edge, a smaller output aperture of the relay lens group 300 can obtain better splitting ability, but a smaller output aperture will reduce the overall light transmission energy of the optical system. Taking the above into consideration, the output aperture of the relay lens group 300 in this application is 15 mm; the focal length is normalized to 1, and the optical system structural parameters of the relay lens group 300 are shown in Table 2.

[0054] Table 2 Optical structure parameters

[0055]

[0056] The technical specifications of the relay lens set 300 are:

[0057] Focal length: 66mm, output aperture: 15mm, F / #: 4.4, working band: 400-650nm; Fig. 9 As shown, the MTF of the relay mirror assembly 300 at the Nyquist frequency of 66 lp / mm is close to the diffraction limit.

[0058] In practical applications, the relay lens group 300 needs to match the optical path with the front zoom telescope group 100, so the relay lens group 300 is an object-side telecentric structure, and the main light emission angle of each field of view at the object plane should be close to , in order to avoid interference with the front zoom telescope group 100 lens, the relay lens group 300 needs to have a long working distance, and the front working distance is 71.44mm.

[0059] In practical applications, such as Fig.10 As shown, the prism-grating-prism 400 is made by bonding a transmission type volume phase holographic grating 402 between two prisms (a first prism 401 and a second prism 403), wherein: represents the wavelength of the beam that satisfies the Bragg condition, represents the optical axis, It is called the internal Bragg angle of the grating; the transmission type volume phase holographic grating 402 can achieve high diffraction efficiency and strong splitting performance, and is an important splitting element of the prism-grating-prism 400.

[0060] The transmission type volume phase holographic grating 402 requires the incident light to be incident at the angle of the Bragg condition to ensure high-efficiency diffraction; the state parameters of the light emitted from the first prism 401 should be used as the incident state parameters of the transmission type volume phase holographic grating 402, that is, the first prism 401 emission angle The Bragg condition formula (3) must be satisfied and incident on the grating. At this time, the diffraction efficiency of the prism-grating-prism 400 is maximum.

[0061] (3)

[0062] Br represents the Bragg coefficient, is called the grating period, represents the grating refractive index, is the grating vector inclination angle; for incident light that does not meet the Bragg condition, the light splitting performance of the transmission type volume phase holographic grating 402 will be reduced; the material of the transmission type volume phase holographic grating 402 is: B270, the line density is: 360l / mm, and the spectral range is 400-650nm; the function of the prism is to make the incident and outgoing light beams on the same axis, the light beams go straight in and out, there is no off-axis system, and the problems of large volume and difficult installation and adjustment are solved; the structural parameters of the first prism 401 include the vertex angle and the material refractive index, when all satisfy the grating Bragg condition, the diffraction efficiency of the transmission type volume phase holographic grating 402 can reach the maximum. The incident light beam is emitted after passing through the prism-grating-prism 400, satisfying the refraction law and the grating equation, and the first prism 401 satisfies the following formula:

[0063] (4)

[0064] in, The first prism 401 is used to represent the wavelength The refractive index, Indicates wavelength The exit angle at the first surface of the first prism 401 is, Indicates wavelength The incident angle on the second surface of the first prism 401, i.e. the wavelength At the incident angle of the transmission type volume phase holographic grating 402.

[0065] Grating equation:

[0066] (5)

[0067] in, Indicates the wavelength above At the output angle of the transmission type volume phase holographic grating 402, i.e., the wavelength The exit angle at the first surface of the second prism 403 is, Represents the grating diffraction order.

[0068] The second prism 403 satisfies:

[0069] (6)

[0070] in, Indicates the wavelength above The incident angle on the second surface of the second prism 403 is, represents the vertex angle of the second prism 403, Indicates wavelength The emission angle at the second surface of the second prism 403.

[0071] Thus, the vertex angle of the first prism 401 can be obtained Constraints:

[0072] (7)

[0073] In the formula, is the angle of the Bragg wavelength beam inside the first prism 401, represents the refractive index of the Bragg wavelength light beam in the first prism 401, Determined by the Schott dispersion formula:

[0074] (8)

[0075] in, to These are the six coefficients of optical glass in the Schott dispersion formula.

[0076] From formula (7), we can see that when the same material is selected, as the vertex angle As the wavelength increases, the peak value of the diffraction efficiency of the prism-grating-prism 400 moves toward the long-wave direction, which has little effect on its spectral bandwidth.

[0077] The material of the first prism 401 needs to have a high transmittance in the spectral range of 400nm-650nm. The larger the dispersion coefficient of the material, the smaller the emission angle of the Bragg wavelength light beam from the first prism 401. The larger the value, the greater the emission angle of each wavelength. and The smaller the difference is, the closer the outgoing light beam of the first prism 401 is to the Bragg incidence condition.

[0078] The technical specifications of Prism-Grating-Prism 400 are:

[0079] The vertex angles of the first prism 401 and the second prism 403 are 10.3° and 12.9° respectively; the material of the first prism 401 and the second prism 403 is BK7; the diffraction efficiency of the prism-grating-prism 400 is not less than 50%.

[0080] In practical applications, such as Fig.11 As shown, the imaging lens group 500 includes: an eighth transmission mirror 501 with positive refractive power, a double-cemented transmission mirror 502 with positive refractive power, a ninth transmission mirror 503 with negative refractive power, a tenth transmission mirror 504 with positive refractive power, and an eleventh transmission mirror 505 with positive refractive power, which are arranged in sequence from the object side to the image side. The imaging lens group 500 is connected to the polarization detector 600. The back intercept needs to consider the detector interface model and should be longer than the distance from the incident port of the polarization detector 600 to the target surface of the polarization detector 600. Preferably, the polarization detector 600 uses the Daheng Image MER-502-79U3MPOL visible light polarization industrial camera. The detector interface is a C port, and the distance from the contact surface to the focal plane of the lens is 17.53 mm. Therefore, the back intercept of the imaging lens group 500 should be longer than this length. In this application, the back intercept length of the imaging lens group 500 is 20 mm. The entrance pupil diameter of the imaging lens group 500 should match the exit aperture of the above-mentioned relay lens group 300, which is 15 mm. The focal length of the imaging lens group 500 should consider the matching problem between the pixel of the image plane of the digital micromirror 200 and the pixel of the polarization detector 600. The following formula is used: (7)

[0081] in, It is a relay lens with a focal length of 300. The focal length of the imaging lens group is 500. The digital micromirror has a pixel size of 200. is the pixel size of the target surface of the polarization detector 600; under the premise of satisfying this formula, the imaging capabilities of optical systems with different focal lengths should also be comprehensively considered. In this application, the focal length of the imaging lens group 500 is 60 mm; the focal length is normalized to 1, and the optical system structural parameters of the imaging lens group 500 are shown in Table 3.

[0082] Table 3 Optical structure parameters

[0083]

[0084] The technical specifications of the imaging lens set 500 are:

[0085] Focal length: 60mm, entrance pupil diameter: 15mm, F / #: 4.0, operating band: 400-650nm; Fig.12 As shown, the MTF of the imaging lens assembly 500 at the Nyquist frequency of 144 lp / mm at a central wavelength of 500 nm is above 0.3, which is close to the diffraction limit.

[0086] In practical applications, the focal length of the front zoom telescope group 100 in the short focus state is 40mm, the focal length of the front zoom telescope group 100 in the long focus state is 120mm, the focal length of the relay lens group 300 is 66mm, and the focal length of the imaging lens group 500 is 60mm. The overall focal length of the snapshot hyperspectral polarization zoom imaging optical system in the short focus state is 36mm, and the overall focal length of the system in the long focus state is 109mm. The field of view in the short focus state is 13.38°, and the field of view in the long focus state is 4.44°. The working band of the snapshot hyperspectral polarization zoom imaging optical system is 400nm-650nm. The spatial resolution in the short focus state is: RS S =0.75 m / pixel@ 5 km , telephoto state spatial resolution: RS L =0.19 m / pixel@ 5 km .

[0087] This application has the following technical effects:

[0088] The front zoom telescope set 100 provided in the present application has the characteristics of long back focus, large image surface, image-side telecentric structure, two-level zoom, etc.

[0089] The imaging spectrometer using the zoom optical system provided in the present application can achieve two-speed zoom, realize optical magnification without changing the target distance, and make it more flexible to use; while the spectral resolution does not change, the short-focus state is switched to the long-focus state to improve the spatial resolution and achieve refined identification of the target; a large area of ​​the target can be searched in the short-focus state, and for points of interest, the zoom can be quickly changed, and the ground area can be distinguished using the long-focus state.

[0090] In the present application, the relay lens group 300 adopts an object-side telecentric structure, which can match front objective lenses with different exit pupil positions, and the system spatial measurement accuracy is higher.

[0091] The polarization spectral imaging technology of the present application (implemented by the prism-grating-prism 400 and the polarization detector 600) obtains the spectral information of each object point and the polarization information at each wavelength while acquiring the two-dimensional image information of the target object, so as to understand the target more comprehensively, accurately and meticulously.

[0092] The present application realizes the acquisition of spectral and polarization multi-dimensional images with a single optical path, a single detector, and a single shot, and real-time acquisition of multi-dimensional information of dynamic targets. It can adapt to fast-moving scenes, accurately, quickly, and in real time discover and lock targets, and realize variable focal length acquisition of data cubes of target space, spectrum, and polarization information, which is beneficial to target detection.

[0093] This application organically combines the spectral information and polarization information of light by setting up a prism-grating-prism and a polarization detector, which is a useful supplement to traditional imaging detection. The rapid switching between short-focus and long-focus states solves the problem that the spatial resolution and spectral resolution of the traditional fixed-focus polarization spectrum imaging system cannot be improved at the same time, and realizes large-area search on the ground in the short-focus state and fine identification of points of interest in the long-focus state. The snapshot detection method solves the problem that the traditional push-broom detection method cannot achieve rapid zoom and cannot take into account the time resolution, thereby improving the system's working efficiency.

[0094] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0095] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. An airborne snapshot hyperspectral polarization zoom imaging optical system, characterized in that: The airborne snapshot hyperspectral polarization zoom imaging optical system comprises: A front zoom telescope group, a digital micromirror arranged on an outgoing light path of the front zoom telescope group, a relay lens group arranged on an outgoing light path of the digital micromirror, a prism-grating-prism arranged on an outgoing light path of the relay lens group, an imaging lens group arranged on an outgoing light path of the prism-grating-prism, and a polarization detector arranged on an outgoing light path of the imaging lens group; The front zoom telescope group includes a front fixed group, a variable magnification group, a rear compensation group, an aperture and a rear fixed group arranged in sequence from the object side to the image side; the variable magnification group slides between the front fixed group and the rear compensation group to achieve zooming; The relay lens group comprises: a first transmission mirror with positive refractive power, a second transmission mirror with negative refractive power, a third transmission mirror with positive refractive power, a fourth transmission mirror with positive refractive power, a fifth transmission mirror with positive refractive power, a sixth transmission mirror with negative refractive power and a seventh transmission mirror with positive refractive power, which are sequentially arranged from the object side to the image side; The back focus distance of the front zoom telescope group is 100mm; When the front zoom telescope group is in the short focus state, the focal length is 40mm, the entrance pupil diameter is 8.9mm, the field of view angle is 23.76°, the F / # is 4.5, and the working band is 400nm-650nm. When the front zoom telescope group is in telephoto mode, the focal length is 120mm, the entrance pupil diameter is 26.7mm, the field of view angle is 8.03°, the F / # is 4.5, and the operating band is 400nm-650nm; The output aperture of the relay lens group is 15mm, and the front working distance of the relay lens group is 71.44mm.

2. The airborne snapshot hyperspectral polarization zoom imaging optical system according to claim 1, characterized in that: The front fixed group has positive refractive power, the variable power group has negative refractive power, the rear compensation group has negative refractive power, and the rear fixed group has positive refractive power.

3. The airborne snapshot hyperspectral polarization zoom imaging optical system according to claim 1, characterized in that: The imaging lens group includes: an eighth transmission mirror with positive refractive power, a double-cemented transmission mirror with positive refractive power, a ninth transmission mirror with negative refractive power, a tenth transmission mirror with positive refractive power and an eleventh transmission mirror with positive refractive power, which are arranged in sequence from the object side to the image side.

4. The airborne snapshot hyperspectral polarization zoom imaging optical system according to claim 1, characterized in that: The front zoom telescope group is an image-side telecentric structure.

5. The airborne snapshot hyperspectral polarization zoom imaging optical system according to claim 1, characterized in that: The relay mirror assembly is an object-side telecentric structure.

6. The airborne snapshot hyperspectral polarization zoom imaging optical system according to claim 1, characterized in that: The digital micromirror is a spatial light modulator.

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