Removing speckle noise and extracting the skeletons from a single speckle fringe pattern by spin filtering with curved-surface windows

Abstract

Removing speckle noise in electronic speckle pattern interfer- ometry (ESPI) from a single speckle fringe pattern while keeping the fringe features is a difficult problem and remains unsolved. In this paper, the spin filtering proposed by the authors is developed further with curved surface windows to filter out speckle noise from a single speckle fringe pattern. With the large curved surface windows, the speckle noise can be removed nearly completely by the spin filtering. The most impor- tant advantage of the method is that no blurring effects occur for speckle fringes and the smooth fringe pattern of a phase field is retrieved and derived. The skeletons of the smoothed fringe pattern are extracted au- tomatically. © 2003 Society of Photo-Optical Instrumentation Engineers.