Binary coded linear fringes for three-dimensional shape profiling

We present a three-dimensional (3-D) shape profiling method that involves the projection of two shifted strictly binary (square wave) fringe patterns, whose adequately weighted average allows to synthesize a sawtooth pattern. We demonstrate that the deformed fringes (after unwrapping) provide an intensity pattern proportional to the depth profile of the surface. The proposed technique overcomes the nonlinear response (i.e., the "gamma problem") of digital cameras and commercial video projectors without previous calibration. The two binary patterns can be encoded in the color components of a single color image, which allows a reliable 3-D profiling surface reconstruction at large time-rates. Validation experiments are presented.