干涉成像系统信噪比的统计分析

根据统计光学建立了干涉成像系统信噪比的理论模型,数值分析了干涉成像系统信噪比与系统参数之间的关系。分析结果表明:为了提高系统的信噪比,应提高信号光场强度与噪声光场强度之比,使参考光和测试光光强接近相等,降低系统中光学元件的数量和每个元件的偏差,使光源相干长度约为测试光和参考光间光程差的2～5倍。要使信噪比大于10,则要求系统中光学元件总偏差的标准差小于1/4波长。信噪比的统计理论模型可为干涉成像系统设计和干涉测量提供理论指导。

Statistical analysis of signal-to-noise ratio in interferometric imaging system

A theoretical model of signal-to-noise ratio(SNR) in interferometric imaging system is proposed by means of statistical optics. According to the theoretical model, relations between system’s SNR and parameters are analyzed numerically and some conclusions are drawn. To obtain high SNR, the ratio of signal intensity to noise intensity should be improved, the intensities of reference and test beams should be matched, the number and roughness of optical elements in imaging system should be decreased, and the coherent length of optical field should be about 2 to 5 times the optical path difference between reference and test beams. In order to make SNR higher than 10, the standard deviation of fabrication error of all optical elements in system must be less than one-fourth of wavelength. The t