Adaptive fringe projection technique for high-dynamic range three-dimensional shape measurement using binary search

Fringe projection profilometry is a popular optical method for three-dimensional (3-D) shape measurement because of its high accuracy, fast measurement speed, and full-field inspection nature. However, due to the limited dynamic range of the digital camera, saturated pixels in the captured images will lead to serious phase errors and measurement errors when the measured object has a drastic texture variation. To deal with such a problem, an adaptive digital fringe projection technique for high dynamic 3-D shape measurement is proposed. In this method, phase-shifting fringes are adaptively generated with the aid of a coordinates mapping process and binary-search technique to eliminate saturation. Compared with previous adaptive fringe projection techniques, the camera response function and homographic mapping between the camera and projector are not needed, making the whole measurement easier to carry out and less laborious. Experiments validate the effectiveness and superiority of the proposed method for high-dynamic range 3-D shape measurement. (C) 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)