APPROACH FOR THE EVALUATION OF SPECKLE DEFORMATION MEASUREMENTS BY APPLICATION OF THE WAVELET TRANSFORMATION

We introduce a new, to our knowledge, method using wavelets and probab ility theory for the evaluation of speckle interference patterns for q uantitative out-of-plane deformation measurements of rough surfaces of nontransparent solids. The experiment uses a conventional Twyman-Gree n interferometer setup. The speckle interference patterns are obtained by the common method of subtraction of images taken before and after a surface deformation. The data are processed by a wavelet transformat ion, which analyzes the image structures on different length scales. T hus it is possible to separate the interference fringes from the noise . From the locations of the interference fringes, the deformation of t he surface can be reconstructed by means of probability theory. (C) 19 97 Optical Society of America.