Linearly coded profilometry

A new optical profilometry-linearly coded profilometry (LCP)-is presented. It uses a sawtoothlike Linear light structure to code the surface to be measured and a phase-shifting technique to decode the profile. Two kinds of coding-light structure, one with right-angle triangle teeth and the other with isosceles triangle teeth, are proposed. For coding with light with right-angle triangle teeth, a general decoding method is given. In addition, an optimum sampling manner and the measurement error are discussed with respect to a special case. For coding with light with isosceles triangle teeth, a decoding method with three samples is given. In our laboratory, an experimental system was established, and experiments that verified the reliability of the proposed methods were performed. Experimental results typical of those obtained are given. We find that LCP is similar to the widely used phase-measuring profilometry but has a faster measuring speed. (C) 1997 Optical Society of America.