Evaluation of stress coverage for varying object loading using Statistical Fringe Processing

Abstract

Ubiquitous in coherent optical metrology, fringe patterns are processed traditionally using manual evaluation that is tedious and is hampered by the presence of speckle noise in the pattern. A fringe processing method based on a statistical algorithm has been reported to be sensitive to fringe densities. The first part of the presentation will cover the method’s basic principles, step-by-step implementation, numerical recipe, as well as some applications in optical metrology. The second part will discuss a novel application of the method in locating and defining the extent or bounding regions of fringes for the case of the loaded plexiglass.  Reconstructed phase maps were processed using the method, identifying characteristic stressed regions for varying amount of loading on a plexiglass sample. Evaluation of the extent of stress coverage has applications in quality control.