一、光学相关原理　　　　光学相关仪如图1所示.　　　　相关分析是一种能从强噪音中拾取弱信号的十分有效的方法.如有两个随机的函数X(t)和Y(t),它们的相关函数表示为　　　　　　如果对R(τ)进行付里叶变换:　　令　t+τ=s,则得　　　　　　从(2)式可知:相关分析相当于 First, the principle of optical correlation Optical correlation instrument shown in Figure 1. Correlation analysis is a very effective way to pick up weak signals from strong noise. If there are two random functions X (t) and Y (t) Their correlation function is expressed as if R (τ) is Fourier transformed: Let t + τ = s, then we can get from (2) that the correlation analysis is equivalent to