Applying autocorrelation method to process laser speckle patterns,the relation between surface roughness and speckle elongation and correlation length of autocorrelation function can be obtained,and then the measured surface roughness can be achieved based on this relation.One-dimension autocorrelation and two-dimension autocorrelation function are used,a Moreover,surface roughness is evaluated by speckle elongation and correlation length of autocorrelation function from different aspects.Aspect ratio of sp...