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

Removing speckle noise in electronic speckle pattern interferometry (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 important 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 automatically. (C) 2003 Society of Photo-Optical Instrumentation Engineers.