An automated technique has been developed for the analysis of various types of interferograms. The technique makes use of a high speed digitized microdensitometer to scan the interferograms and a high speed computer to perform the required computations. The optical thickness variations for a test specimen can be determined by analysis of one or two interferograms. In addition, when required, determinations can be made of time change in optical thickness or the physical thickness and index of refraction homogeneity profiles by analysis of multiple interferograms.
Robert A. Jones and Pravin L. Kadakia, "An Automated Interferogram Analysis Technique," Appl. Opt. 7, 1477-1477 (1968)