The growth of modern interferometry for industrial inspection

Two major developments in interferometry are discussed. One is the availability of cheap reliable He-Ne lasers, which have replaced expensive, unreliable and unwieldy sources with a device with is compact and cheap. The most recent product, coherent laser diodes, give extremely robust and reliable sources in a very small semiconductor package. The other development is the growth of computer technology, which has made high speed digital image processing available at low cost to most workers in the field. The analysis of interferograms is an algorithmic issue