Digital image frequency spectrum method for analyzing speckle displacement in frequency domain

摘要

A technique called the digital image frequency spectrum (DIFS) method, used for analyzing digital speckle patterns with deformations in the frequency domain, is proposed. Two subimages in the same position as two digital speckle patterns before and after deformation are used to form a Young's fringe. The parallel Young's fringe pattern is automatically analyzed in the frequency domain. One finds that the displacement between the two subimages can be directly obtained, and a matching procedure used in digital image correlation (DIC) is unnecessary when DIFS is applied. Experimental results show that the relative error of this method is less than 3%, and it takes less time in computing integer-pixel displacement procedure. (C) 2015 Optical Society of America