A kind of programmable polarization hyperspectral imager based on field stitching
Technical field
The utility model relates to a kind of polarimetric hyperspectral imager, be specifically related to a kind of based on field stitching, can obtain the cross polarization spectrogram simultaneously as programmable polarization hyperspectral imager information, that have multispectral section complex imaging ability.
Background technology
Utilize spectrum picture information can obtain the chemical feature and the space distribution information thereof such as material composition, content of target, thereby imaging spectral technology is with a wide range of applications in the national economy fields of society.At first, imaging spectrometer can be used as the useful load of spacecraft, utilizes its spectral information that obtains can be applied to following field: land resources survey (ore prospecting, city planning, outskirts of a town land classification utilizes, desertification of land improvement and soil erosion monitoring etc.), forestry (forest resourceies investigation and the monitoring of deforestation afforestation etc.), ecological (environmental monitoring, land ecological Studies and region environment evaluation etc.), agricultural (large tracts of land agricultural resource monitor, the crop yield prediction, the analyses and prediction of crops growing way, pest and disease monitoring etc.), survey of deep space (the moon, the mineral prospecting of celestial bodies such as Mars, solar system planetary scale detection etc.) field such as.
Secondly, spectral analysis technique also is widely used in industry-by-industries such as food and drink, petrochemical complex, weaving, clinical medicine.
Polarization image information provides physical features and space distribution informations thereof such as roughness about target, water cut, voidage, diameter of particle.
Polarization remote sensing is compared with traditional remote sensing, and many unique distinctions are arranged, and it can solve the more insurmountable problems of common photometry, cloudlike with aerocolloidal size distribution etc.
Scattered light from atural object often is a linearly polarized light, has degree of polarization more than 20% as the scattered light on crown canopy covering, arable land, grassland, the reflected light of the mud bank and the water surface has the degree of polarization more than 50%, different atural objects have different polarization characteristics, and man-made target often has the polarization characteristic stronger than natural target, utilize these polarization informations can be finally inversed by tenor in the physical arrangement, water content, rock of ground object target etc., monitoring seawater pollution situation is surveyed the Size Distribution of the distribution of hemisphere cloud, kind, height and atmospheric aerosol particle etc.
Undoubtedly, compare with the imaging polarization technology with imaging spectral technology, that the polarimetric hyperspectral imaging technique can obtain is more detailed, target information more fully.
Imaging spectral technology can be divided into interfere type (spatial modulation type according to light-dividing principle, the time modulation type), color dispersion-type (grating type and prism-type) and optical filtering type (rotating filtering sheet, liquid crystal tunable light filter (Liquid CrystalTunable Filter, LCTF), acousto-optic tunable filter (Acousto-Optic Tunable Filter, AOTF) etc.) three kinds, every kind all has its relative merits and the scope of application thereof, wherein based on acousto-optic tunable filter (AcoustoOptic Tunable Filter, AOTF) imaging spectral technology has dirigibility (the spectrum channel order or tuning at random that spectrum channel and spectral transmittance can electric tuning provide fast, hyperchannel obtains simultaneously, the intelligent independent spectrum channel is selected and is obtained, realize rectangle spectral response curve etc.), the structural compactness that movement-less part brings (adapting to abominable mechanical environment), need not complex data handles the ease for use of bringing and can obtain polarization simultaneously, many characteristics such as integration of multidimensional information such as spectrum and image (improving the ability of target detection and identification), and be with a wide range of applications.
Because natural light produces the arrowband O light and the E light of polarization state quadrature behind the AOTF diffraction, gather arrowband O light and E light image simultaneously and can constitute simple and the compactest polarimetric hyperspectral imaging system (Li-JenCheng, Tien-Hsin Chao, Mack Dowdy, Clayton LaBaw, Cohn Mahoney, GeorgeReyes, " Multispectral imaging systems using acousto-optic tunable filter ", Proc.SPIE Vol.1874, pp.223-231,1993.).But the prior art scheme has following defective: (1) needs two detectors to go to obtain respectively O light image and E light image, makes the system architecture complexity undoubtedly, and cost increases; (2) do not compensate the image drift that AOTF causes when tuning, thereby cause restoring spectrum because of spectral coverage aliasing signal-to-noise ratio degradation; (3) the AOTF drive unit adopts the DDS chip, can only be operated in the single-frequency pattern, can't obtain multispectral section combination picture under the multifrequency pattern.
The utility model content
In order to solve the above-mentioned technical matters that exists in the background technology, the utility model provides a kind of to synthesize O light image and E light image on same detector light-sensitive surface, carries out the image drift compensation and realize the programmable polarization hyperspectral imager that multifrequency AOTF drives based on the AWG (Arbitrary Waveform Generator) scheme by wedge compensation and image registration mode by field stitching.
Technical solution of the present utility model is: the utility model provides a kind of programmable polarization hyperspectral imager based on field stitching, and its special character is: described programmable polarization hyperspectral imager based on field stitching comprises preset lens, field stop, collimating mirror, acousto-optic tunable filter, imaging mirror, detector and detector control processing system; Described preset lens, field stop, collimating mirror, acousto-optic tunable filter are successively set on the same light path; O light light path behind the acousto-optic tunable filter diffraction is provided with O light light path turnover system; E light light path behind the acousto-optic tunable filter diffraction is provided with E light light path turnover system; Described through O light light path turnover system turnover O light light beam and converge on the detector light-sensitive surface that is positioned on the imaging mirror back focal plane by the imaging mirror together through the E light light beam of E light light path turnover system turnover; Described detector links to each other with the detector control processing system.
Above-mentioned O light light path turnover system comprises turning mirror of O light and O light secondary turning mirror; Turning mirror of described O light and O light secondary turning mirror place between acousto-optic tunable filter and the imaging mirror.
The above-mentioned O light light path system that transfers also comprises O light wedge; Described O light wedge places the collimated light path between turning mirror of O light and the imaging mirror.
Above-mentioned O light wedge is the combination of monochromatic light wedge or a plurality of monochromatic light wedges.
Above-mentioned E light light path turnover system comprises turning mirror of E light and E light secondary turning mirror; Turning mirror of described E light, E light secondary turning mirror place between acousto-optic tunable filter and the imaging mirror.
The above-mentioned E light light path system that transfers also comprises E light wedge; Described E light wedge is arranged in the collimated light path between turning mirror of E light and the imaging mirror.
Above-mentioned E light wedge is the combination of monochromatic light wedge or a plurality of monochromatic light wedges.
Above-mentioned programmable polarization hyperspectral imager based on field stitching also comprises the acousto-optic tunable filter driver that electrically connects with acousto-optic tunable filter, and described acousto-optic tunable filter driver is based on the AWG (Arbitrary Waveform Generator) of the integrated structure of the integrated structure of FPGA and DAC or CPLD and DAC.
Above-mentioned programmable polarization hyperspectral imager based on field stitching also comprises the optical trap that is used to reduce the inhibition zero order diffracted light that the veiling glare to O light image and E light image disturbs, and described optical trap is arranged on the exit end of acousto-optic tunable filter.
Above-mentioned detector is ultraviolet detector, visible-light detector or infrared eye; For ultraviolet detector especially ultraviolet CCD; For visible-light detector, especially CCD, CMOS or EMCCD.
The utility model has the advantages that:
1, field stitching.The utility model is with the O light image face and the E light image face diverse location of optics splicing apparatus splicing at same detector light-sensitive surface of two separation in the prior art, thereby two cover detector control processing system in the prior art are united two into one, simplified system architecture greatly, make that the instrument volume is little, in light weight, compact conformation, the anti shock and vibration ability is strong, has stronger space environment adaptive faculty.
2, image drift compensation.The utility model is provided with O light wedge and E light wedge respectively in O light turnover light path and E light turnover light path, the utility model that is arranged so that of these parts can compensate image drift, in addition, O light spectrum picture and the E light spectrum picture that collects carried out the further removal of images drift of spectral coverage registration with image registration algorithm, thereby improve polarization spectrum recovery accuracy and signal to noise ratio (S/N ratio).
3, multispectral section complex imaging.The utility model substitutes existing acousto-optic tunable filter driver with the multifrequency driver, can realize multispectral section complex imaging.
Description of drawings
Fig. 1 is the utility model structural representation.
Embodiment
Referring to Fig. 1, the utility model provides a kind of programmable polarization hyperspectral imager based on field stitching, comprises preset lens 2, field stop 3, collimating mirror 4, acousto-optic tunable filter 5; Preset lens 2, field stop 3, collimating mirror 4, acousto-optic tunable filter 5 are successively set on the same light path; O light light path behind acousto-optic tunable filter 5 diffraction is provided with O light light path turnover system 18, E light light path behind acousto-optic tunable filter 5 diffraction is provided with E light light path turnover system 19, and the zero order diffracted light light path behind acousto-optic tunable filter 5 diffraction is provided with optical trap 6; Through the O light light beam of O light light path turnover system 18 turnovers and after the E light light beam splicing of E light light path turnover system 19 turnovers together by imaging mirror 13, imaging mirror 13 is successively with detector 14, detector control processing system 15 with control acquisition processing system 16 and link to each other.
O light light path turnover system 18 comprises turning mirror 7 of O light, O light secondary turning mirror 8 and O light wedge 9 successively.O light light path turnover system 18 is arranged at acousto-optic tunable filter 5 exit end zero order diffracted lights and separates the place fully with first-order diffraction light.In order to eliminate acousto-optic tunable filter 5 caused image drift when tuning, in the collimated light path between turning mirror 7 of O light and imaging mirror 13 O light wedge 9 is set, O light wedge 9 is combinations of monochromatic light wedge or a plurality of monochromatic light wedges.
E light light path turnover system 19 comprises turning mirror 10 of E light, E light secondary turning mirror 11 and E light wedge 12 successively.E light light path turnover system 19 is arranged at acousto-optic tunable filter 5 exit end zero order diffracted lights and separates the place fully with first-order diffraction light.In order to eliminate acousto-optic tunable filter 5 caused image drift when tuning, in the collimated light path between turning mirror 10 of E light and imaging mirror 13 E light wedge 12 is set, E light wedge 12 is combinations of monochromatic light wedge or a plurality of monochromatic light wedges.
The optical material dispersion characteristics of O light wedge 9 and E light wedge 12 should be complementary with the dispersion characteristics of acousto-optic tunable filter 5 acousto-materials, and its design parameter should be optimized, so that the caused detector 14 light-sensitive surface epigraphs drift of acousto-optic tunable is less than 1/10th pixels.
Should also comprise the optical trap 6 that is used to reduce the inhibition zero order diffracted light that the veiling glare to O light image and E light image disturbs based on programmable polarization hyperspectral imager of field stitching, optical trap 6 is arranged on acousto-optic tunable filter 5 exit end zero order diffracted lights and separates the place fully with first-order diffraction light.
Should also comprise the acousto-optic tunable filter driver 17 that electrically connects with acousto-optic tunable filter 5 based on programmable polarization hyperspectral imager of field stitching, this acousto-optic tunable filter driver 17 is based on the AWG (Arbitrary Waveform Generator) of the integrated structure of the integrated structure of FPGA and DAC or CPLD and DAC.
Detector 14 is ultraviolet detector, visible-light detector or infrared eye; For ultraviolet detector especially ultraviolet CCD; For visible-light detector, especially CCD, CMOS or EMCCD.
The work mould that control acquisition process computing machine 16 is provided with detector control processing system 15 and acousto-optic tunable filter AOTF driver 17 is executed and running parameter, the spectrum channel of tuning acousto-optic tunable filter 5, gather the O light spectrum picture and the E light spectrum picture of a series of different spectral coverage of detector control processing system 15 outputs, further compensate the acousto-optic tunable filter image drift by the image configurations algorithm, obtain the polarimetric hyperspectral view data cube of object scene at last by the polarization spectrum inversion algorithm.
Provide specific embodiment of the utility model below in conjunction with accompanying drawing:
In order to guarantee wide spectrum image quality and polarization spectrum signal to noise ratio (S/N ratio), preset lens 2, collimating mirror 4, imaging mirror 13 adopt the apochromatism design, guarantee that total system monochromatic light blur circle diameter is less than the pixel dimension of detector 14 in full spectral coverage scope.In order to make full use of the effective aperture of acousto-optic tunable filter 5, the entrance pupil of the emergent pupil of collimating mirror 4 and imaging mirror 13 should be arranged on the center of acousto-optic tunable filter 5.
Detector 14 can be ultraviolet detector (ultraviolet CCD), visible-light detector (CCD, CMOS, EMCCD etc.) or infrared eye.
Acousto-optic tunable filter 5 is as tunable filter, and driving frequency that can tuning acousto-optic tunable filter 5 is to select interested arrowband polarization spectrum image.Acousto-optic tunable filter 5 adopts the non-colinear design, acousto-material can be TeO2, TAS etc., and the O light of the two-way polarization state quadrature of its output and E light all can be transferred splicing after the cross polarization spectrogram picture that 13 acquisitions of imaging mirror are stitched together through O light light path turnover system 18 and E light spectrum turnover system 19 respectively on detector 14 light-sensitive surfaces.
Zero order diffracted light adds optical trap 6 to the influence of first-order diffraction light at the zero order diffracted light light path terminal in acousto-optic tunable filter 5 outgoing beams in order to suppress, so that the stray light of its generation is as far as possible little.
It is as follows that this polarimetric hyperspectral imager gets the course of work:
Emission, reflection or transmitted light from object scene 1 obtain image planes at its back focal plane place after preset lens 2 is collected.The field stop 3 that is positioned at preset lens 2 image planes places is constrained to the picture field range.An image planes picture of target is divided into O light light beam and E light light beam after preposition collimating mirror 4 collimations, acousto-optic tunable filter 5 beam split.O light light beam is via turning mirror 7 of O light, O light secondary turning mirror 8, O light light path turnover system 18 turnovers that O light wedge 9 is formed, E light light beam is via turning mirror 10 of E light, E light secondary turning mirror 11, after E light light path turnover system 19 turnovers that E light wedge 12 is formed, on detector 14 light-sensitive surfaces, obtain the O light spectrum picture and the E light spectrum picture that are stitched together by imaging mirror 13, after handling and control acquisition process computing machine 16 acquisition process, detector control processing system 15 obtains O light spectrum digital picture and E light spectrum digital picture, after gathering and handling the O light spectrum digital picture and E light spectrum digital picture of a series of spectral coverages, after image registration and spectrum inverting, form the polarimetric hyperspectral view data cube of object scene 1.Control acquisition process computing machine 16 can be selected interested arrowband polarization spectrum image or multispectral section combination picture by the drive signal frequency number and the frequency values of 17 outputs of guide sound optic tunable filter driver, the diffraction efficiency that the power by guide sound optic tunable filter driver 17 output drive signals can guide sound optic tunable filter 5.