Novel quasi absolute phase unwrapping algorithm for 3D optical measurement

Obtaining fringe order map accurately and quickly can achieve high-precision optical three-dimensional (3D) measurement. To retrieve the absolute phase map, this letter presents a novel quasi absolute phase unwrapping method based on N+1 step line-coded phase-shifting profilometry (LPSP). Fringe order can be determined easily from wrapped phase and the single-pixel binarized (SPB) line pattern, the error occurring at the previous points will not be propagated along the phase unwrapping path, which can effectively avoid error accumulation.精准且快速地获取条纹级次图（fringe order map），可实现高精度光学三维（3D）测量。为恢复绝对相位图（absolute phase map），本文提出一种基于N+1步线编码相移轮廓术（LPSP）的新型准绝对相位展开法。条纹级次可通过包裹相位（wrapped phase）与单像素二值化（single-pixel binarized, SPB）线图案便捷确定，且前序点产生的误差不会沿相位展开路径传播，可有效避免误差累积。