3D shape measurement of specular surface based on structured light coding method

Abstract

Present a novel method for 3D shape measurement of specular surface based on structured light coding method. Coded fringe pattern are projected onto the high reflected surface of the measured object. The deflection fringe pattern that modulated by the object surface are captured by the CCD camera. Central perturbation phase-shift technology is adopted to fast retrieve the phase distribution on the deflection fringe pattern. Then the slope information can be obtained by analyzing the relationship between the phase deflection and the slope of the object surface. By combining the character of the phase-shifting fringe pattern and digital image processing technologies the boundary of the measured object can be picked up from the background before reconstruction, which can reduce the quantities of data to be processed and advance the reconstruction precision at the boundary. The improved wave-front reconstruction method is used to reconstruct the surface. With the application of this technology the 3D shape of specular surface can be precisely reconstructed.