Projection fringe interferometry provides a useful technique for nondestructive surface analysis. Two beam interferometric fringes were projected onto a block of aluminum whose surface had various types of grooves cut into it. The fringes were digitized and analyzed via an automatic fringe tracking algorithm. Threedimensional topographical maps of the surface's microstructure are presented together with a statistical analysis of surface parameters including average roughness, height distributions, and the autocorrelation function.

Micro -topographic analysis of surfaces, particularly of the non -optical type are of great interest in various areas of science and technology.A technique and results on topographic mapping of surfaces are presented. Essentially, the method uses advanced software for image processing of the pattern of the contouring fringes resulting on the surface from illumination by collimated interference fringes.Inherent noise inconvenients are overcome by specially conceived algorithms leading to a best fit symbolic fringe pattern (ideal contouring fringes). From the topological map, statistical parameters are evaluated to characterize the surface.These include: range and distribution of surface heights, average roughness and the auto -correlation function of the surface.

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Optical Fourier transforms of haddock fish scales were made for fish taken from two different bodies of water. The scales in each group varied in age from 2 to 10 yr. A comparison of the image processed digitized Fourier transforms for the scales was made on a personal computer. Statistical correlation studies of these transforms were performed, and the results show a fairly good age discrimination between the scales in each age group.