从统计光学出发,建立了带旋转毛玻璃干涉成像系统的信噪比理论模型,分析旋转毛玻璃参数、光场相干性与系统信噪比之间的关系.模拟计算和实验结果表明:旋转毛玻璃降低了干涉成像系统中光场的相干性,增大了曝光时间内采集的不相关散斑场个数,从而抑制了相干噪声;旋转毛玻璃表面粗糙度的增大,相关长度的缩短,转速的提高都会减小光场的相干时间.为了得到较理想的系统信噪比,应控制旋转毛玻璃参数使旋转周期约等于CCD曝光时间,并使光场相干长度为测试光和参考光间光程差的2～5倍.%The theoretical model of signal-to-noise ratio(SNR) in the interferometric imaging system with rotating diffuser is proposed by means of statistical optics.According to the theoretical model, the relations between parameters of rotating diffuser,coherent time and SNR of the imaging system are analyzed numerically and demonstrated experimentally.It is shown that the rotating diffuser reduces coherent time, increases the number of unrelated speckle noises in gathering time, and thus reduces the speckle noise.An increasing in roughness or rotating frequency of diffuser or a decreasing in coherent length leads to a decreasing in coherent time.To obtain high SNR, the rotating diffuser should be well controlled so that the rotating period is approximately equal to the exposure time of CCD, and the coherent length of optical field is about 2～5 times as long as the optical path difference (OPD) between reference and test beams.
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