Practical three-dimensional computer vision techniques for full-field surface measurement

Abstract

Two practical computer-aided optical techniques for full-field surface shape measurement are presented, one for diffuse surfaces and the other for specularly reflective surfaces. The former technique is based on projecting a computer-generated fringe pattern onto a diffuse surface, and the latter is based on reflecting the fringe pattern from a specularly reflective surface. The fringe pattern is perturbed in accordance with the object surface with the fringe phase bearing information on the depth/slope of the object surface. The computer-generated fringe pattern conveniently enables the fringe phase to be manipulated, and hence the determination of the phase distribution using a phase extraction algorithm. Instead of deriving the mathematical relationship between the fringe phase distribution and the surface depth/slope, this relationship is obtained by calibration. The techniques described can be easily implemented for rapid measurement of 3-D surface shapes in an industrial setting.