AN ALGORITHM FOR THE FAST DERIVATION OF LINE STRUCTURES FROM INTERFEROGRAMS

There are essentially two methods of analyzing fringe patterns - the fringe skeleton method and the phase sampling method. The object of this article is to show how lines of equal phase may be extracted from an interferogram with a sinusoidal intensity modulation by the application of a fringe skeleton method. We interpret the interferogram as an intensity profile and extract valleys, slopes and ridges by consideration of the characteristic rotational invariants in neighborhood relations based on local grey-level differences. As a result, binary line structures are derived for ridges as well as for valleys, which can be thinned to a skeleton of bright and dark fringes.