Unwrapped phase correction for robust 3D scanning

Abstract

A temporal phase unwrapping method is proposed to generate an unwrapped phase map for a robust three-dimensional (3D) scan. The proposed algorithm seeks to improve the accuracy of the 3D data points obtained through the phase unwrapping process. By applying the k-nearest-neighbor search method, the error bound of the wrapped phase is controlled with improved flexibility. To achieve the desired scanning quality, a series of fringe patterns is generated with multiple phases at three different frequencies. For this method, the pattern is shifted by utilizing a six-step temporal phase unwrapping process. In this unwrapping process, the error bound is controlled by employing the k-nearest-neighbor search method and spatial comparison method to obtain an accurate fringe order. Through our correction method, the wrapped phases can be unwrapped more accurately and thus enhance the robustness of the scanning system compared to previous phase unwrapping methods.