AUTOMATIC YOUNG FRINGE ANALYSIS IN THE SOURCE IMAGE PLANE

Typically Young's fringe pattern automatic analysis from a double-expo sure image (e.g. a photograph) passes through an in&rect processing st age on some intermediate parameter domain. Here, we propose a method b ased on a complicated image processing technique, operating directly w ith the source fringe image pixels, and providing remarkable accuracy and computational time. This method is intended for laser speckle velo cimetry (LSV), particle image velocimetry (PIV), and digital image vel ocimetry (DIV) applications. Assuming a common fringe pattern model, w e introduce a pre-processing stage to improve significantly the fringe discernment. A dynamic thresholding segmentation scheme, adjusted to the fringe spatial structure, follows to localize the fringes being qu antitatively attributed with the corresponding eigenvectors. The algor ithm has been tested on real patterns as well as on a set of artifical ly simulated images with pre-defined characteristics.