Study On Technology Of Mid-infrared Hyperspectral Imaging Based On AOTF

Infrared hyperspectral imaging technology is used to collect spatial,spectral and temperature information of the target by just once detection as it has both the ability of infrared thermal imaging and function of composition spectral analysis.Recently,a kind of staring hyperspectral detection system based on AOTF becomes to be a research hotspot as its small shell,quick tuning and stable structure.This paper pays attention to the research of mid-infrared hyperspectral imaging technology for target detection in complex environment from acouto-optic tuning relation,optical system,electronic system and data processing method.Firstly,this paper introduces the applications and the developing status of hyperspectral imaging,and makes sure the meaning of study on mid-infrared hyperspectral imaging technology based on AOTF.A model of abnormal Bragg diffraction in anisotropic crystal is built,from which the function of acousto-optic tuning relation can be calculated.A kind of acousto-optic tunable filter model made up of TeO2 crystal and LiNbO3 piezoelectric transducer is found.Secondly,with the analysis of AOTF and cooling mid-infrared detector,this paper designs assembling lens on the principle of 100% cold shield efficiency to eliminate stray light.For characteristic of acousto-optic tuning relation in mid-infrared band,a structure of telecentric lens is designed to make the incident rays enter the crystal as a taper.Thirdly,the circuit diagram is finished,which has the high performance FPGA chip as the core to deal with huge hyperspectral data.To solve the problem that the data velocity difference between FPGA and Cameralink port,a ping-pong buffer structure is designed to guarantee the integral data.The two-point method is compiled for nonuniformity correction and blind element inspection to improve imaging quality.Finally,the whole mid-infrared hyperspectral imaging system based on AOTF is integrated.A programme is compiled to catch spatial images and emission curves from the data cube.The center wavelength of target's emission peak can be calculated by a statistic method.A simulation experiment is finished to prove that this staring mid-infrared hyperspectral imaging technology based on AOTF has the ability to detect and identify infrared stealth targets.