Correcting phase unwrapping errors with color phase shifting method

3-D shape measurement techniques have applications in such diverse areas as industrial inspection, reverse engineering, robotic vision, computer graphics, medical diagnosis, etc. Structured light techniques based on sinusoidal phase shifting methods are widely used for 3-D profile measurement due to their measurement speed and accuracy. However, phase-unwrapping algorithms have difficulty in correcting phase unwrapping error due to random wrong order of fringe pattern in specular object. Therefore, it is difficult for the conventional phase shift approach to apply for 3D shape measurement of specular object. In this paper, we propose a novel color phase shift approach to allow to correct phase unwrapping error for specular object.