Contouring by Electronic speckle Pattern Interferometry (ESPI)

Abstract

A method of optically contouring object surfaces for inspection purposes, based on electronic speckle pattern interferometry is described. The technique forms a "bolt-on" addition to existing ESPI systems. It is shown that the correlation fringe contours thus obtained are equivalent to those of projected, two-beam interference fringe contours. Attractive features are the possibility of identifying a stationary reference contour, economy of light usage, and the possibility of programmable control of sensitivity.