A correlation-based phase unwrapping method for Fourier-transform profilometry

A new phase unwrapping algorithm based on correlation map for Fourier-transform profilometry (FTP) method is presented in this paper. It is a quality-guided phase-unwrapping method. The modulation is used as an effective parameter to indicate the reliability of the fringe image for the quality-guided phase-unwrapping method. A filtering window is introduced to calculate the modulation easily. A correlation-map function is proposed to calculate the reliability of the fringe image and to avoid choosing the width of the window in calculating the modulation. As the value of the correlation-map function is lower in areas of the local shadow and abrupt discontinuity than that in other areas, the correlation-map function is used as a guide to find the optimized phase-unwrapping path. The experimental results show that the method is feasible.