Research On The Performance Evaluation Method Of AOTF Polarization Spectral Imaging System

As the organic combination of spectral imaging technique and polarization imaging technique, polarization spectral imaging technique provides a richer source of information for target detection and recognition. Non collinear acousto-optic tunable filter (AOTF) is usually used as splitting element, at the same time, the diffraction light of AOTF is vertical linear polarized light. So it has great potential in the application of polarization spectral imaging technology.For the electro-optical imaging system, imaging performance and image quality evaluation play an important role in performance evaluation, calibration of equipment, optimization design and so on. As an important aspect of imaging system performance evaluation, the optical system image quality evaluation method usually is star-point method, resolving method and transfer function method. But these traditional methods can not express the change of polarization information and spectral information, which is not completely suitable for the AOTF polarization spectral imaging system. In view of the above problems, this paper does the following research:Firstly, according to the working principle of AOTF, the method of full polarization detection based on AOTF and liquid crystal variable retarder (LCVR) is proposed. Analyze the spread of light energy by the way of imaging chain. The polarization spectral imaging chain has been divided into four modules:atmospheric radiation transmission, optical system, detector system and platform system. And the modulation transfer function (MTF) of each module is modeled and simulated.Secondly, according to the polarization state of light and its description, analyze the full polarization detection principle of polarization spectral imaging system based on LCVR and AOTF that proposed in this paper. Optical transfer matrix is introduced and proposed to analyze the performance of AOTF polarization spectral imaging system, which is the extension of traditional optical transfer function.Finally, based on the model of spectral imaging chain and optical transfer matrix, the imaging chain simulation of AOTF polarization spectral imaging system is established in Matlab, and the simulation results are analyzed and compared with experimental results. The results show that the optical transfer matrix combines with the model of imaging chain can be more comprehensive and realistic to evaluate the imaging quality of imaging system.