Removing speckle noise from speckle fringe patterns by spin filtering with curved surface windows

Removing speckle noise of electronic speckle pattern interferometry (ESPI) from a single ESPI fringe pattern while keeping the fringe feature 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 off speckle noise from a single speckle fringe pattern. With the new filtering, the speckle noise can be removed nearly completely from a single speckle fringe pattern. The most important advantage of the method is that no blurring effects occur for speckle fringe patterns and the smooth fringe pattern of a phase field is retrieved and derived.