Automated Moire Contouring Of Diffuse Surfaces

A simple new method of automatically reconstructing the 3-D surface of an object from 2-D moire patterns is proposed. The method can automatically and accurately obtain phase value at every pixel point without assigning fringe orders and interpreting data in the regions between fringes by using a discrete cosine transform based algorithm, which is free from errors caused by the higher harmonic components, the variation of dc light level, and the modulations of amplitudes on a fringe pattern. The method is capable of fully automatic distinction between depression and elevation on an object surface. Theoretical analysis and experimental verification are presented.