Study On The Optical System Of An Infrared Dual-band Scene Simulator

Infrared dual waveband imaging system becomes the research hotspot of theinfrared domanial because of its all weather adaptability to environment, capacity ofresisting disturbance and complementation of dual waveband information content.To test and measure the performance of infrared dual waveband imaging systemprecisely and on the basis of the operating principle of infrared optics and digitalmicromirror, in this thesis, we investigate the development status of visualsimulation system; research the modulating characteristic of digital micromirrordevice as a infrared modulator; contrastively analyse characteristics of twoillumination methods for DMD; design a DMD-based mid-long infrared wavebandvisual simulator, labor its contrast influential factors, and finally the system meetsthe requirement of high-precision simulation experiment; deduce DMD modulationtransfer function curve; obtains the spectral transitive relation of overall infraredlive-action simulation experiment. Main research results are as follows:1) To extend the working waveband from visible light to infrared light perfectly,we studys DMD infrared modulation characteristic and calculates the lightdistribution of different wavebands modulated by the micromirror device on thebasis of diffraction principle. By simulation on Matlab and according to DMDmodulation characteristic of infrared waveband, we design two relavant illuminationsystems and make contrastive analysis of them. Finally, the illumination uniformity reaches97.3%.The system decreases illumination system’s size, restrains stray lightand meets the simulation requirements.2) To meet the test and measure requirements of mid-long infrared wavebandguiding system, we design a DMD-based infrared dual waveband scene simulationoptical system. We discuss the aberration characteristic and design method of largeexit pupil and large back working distance infrared dual waveband projection system.Combining inverted-telephoto structure with a harmony diffraction surface，we balance thecoma aberration, astigmatism, distortion and chromatism aberration introduced bydual waveband, large exit pupil and large back working distance. The system meetsthe high quality simulation requirements of mid-long infrared dual waveband.3) Begin with the basic structure of digital micromirror device, after makingfourier expansion on the modulated light distribution, we finally obtains therelationship curve of DMD transfer function with the fill factor, contrast and space.We also finish the theoretical deduction and computer simulation.4) On the basis of the above work and the image sourse transfer function, weconsider the influence of MTF, sampling of simulation system, undertest system andundertest system detecter respectively. Finally, we obtain the spectral transfercharacteristic under different pixel mappling relation and packing ratio, which willprovide precise forecast for the development of future simulation system.