A noise-immune method of phase unwrapping in speckle interferometry

A new phase unwrapping method that has the advantage of unwrapping of phase distribution with severe noise such as those obtained in speckle interferometry is proposed. First, computer simulations were carried out to examine the performance of the proposed method. Speckled noisy data were generated in the computer, and various types of filters having different sizes for the windows were used to carry out the phase unwrapping. It is found that the method is largely capable of phase unwrapping, and it works quite well even when the human eye cannot recognize clearly the phase jumps due to noise. Finally, the present method was applied to experimental phase distribution obtained by the speckle-shearing interferometer. The proposed method is quite simple and effective from the point of computations involved. Copyright (C) 1996 Elsevier Science Ltd.