3-D Measurement Method for Multireflectivity Scenes Based on Nonlinear Fringe Projection Intensity Adjustment

The 3-D measurement methods based on fringe projection intensity adjustment (FPIA) have been widely adopted to measure the multireflectivity scenes. However, the signal-to-noise ratios (SNRs) of the captured fringe patterns in the FPIA-based methods are reduced because of a large range of reflectivity variations (LRRVs). In our research, a reflection model and a crosstalk model are built to analyze the disturbances induced by LRRVs on the SNRs in the captured fringe patterns, and then, a 3-D measurement method based on nonlinear FPIA (NLFPIA) is proposed to alleviate the LRRV-induced disturbances and improve the measurement accuracy. Moreover, to improve the efficiency of the proposed 3-D measurement method, we present a cyclic utilization of fringe patterns (CUFPs) technique to decrease the number of projection patterns. Experimental results show that the proposed NLFPIA-based 3-D measurement method reduces the root-mean-square error (RMSE) in the measurements of the two standard ceramic geometries by 52.9845% and 36.6393% compared with the FPIA-based method.