双三步相移Double three-step phase-shifting algorithm.pdf

Double three-step phase-shifting algorithm Peisen S. Huang, Qingying J. Hu, and Fu-Pen Chiang We describe what we believe is a new phase-shifting algorithm called a double three-step algorithm developed to reduce the measurement error of a three-dimensional shape-measurement system, which is based on digital fringe-projection and phase-shifting techniques. After comparing the performance of different existing phase-shifting algorithms, we present the new double three-step algorithm based on the error analysis of the standard three-step algorithm. In this algorithm, three-step phase shifting is done twice with an initial phase offset of 60° between them, and the two obtained phase maps are averaged to generate the final phase map. Both theoretical and experimental results showed that this new algo- rithm worked well in significantly reducing the measurement error. © 2002 Optical Society of America OCIS codes: 120.6650, 120.5050, 120.2650, 150.6910, 150.3040, 050.5080. 1. Introduction There is no phase-shifting error in this system be- Since the introduction of phase-measuring methods cause the fringe patterns are generated by software. in the late 1970s and early 1980s,1,2 the resolution, The use of the latest digital fringe-projection tech- accuracy, and repeatability of interferometry and nique improves measurement performance in terms moire´ technology have been greatly improved. Over of measurement speed and accuracy. In developing the years various phase-measuring methods have