Abstract
In the fast 3D shape measurement of complex objects, the process of phase unwrapping affects the measurement accuracy and measurement speed. To omit phase unwrapping, a fast 3D shape measurement method is proposed based on S-transform profilometry and sub-pixel refinement. In this work, Deformed fringe pattern is analyzed based on S-transform to get wrapped phase. To reduce the effect of phase unwrapping, a stereo vision system is employed. Firstly, a deformed fringe pattern is directly used and a hybrid function is proposed to get an initial parallax. Secondly, a phase slope algorithm is proposed to confirm edge point. At last, sub-pixel parallax is refined fromIcoordinate. Experiments are carried out to verify the feasibility and advantage of the proposed method. Results verify that the proposed method can provide fast and accurate 3D shape measurement of complex objects, especially for discontinuous objects and shiny objects.
An Error-Reduction Method for Temporal Phase Unwrapping Based on Double Three-Step Phase-Shifting and Least-Squares Fitting