Phase unwrapping algorithm based on fringe density analysis in Fourier transform profilometry

A new phase unwrapping algorithm based on fringe frequency analysis in Fourier Transform Profilometry (FTP) is presented. By the frequency weighted filtering, the analysis of fringe density is converted into the analysis of fringe modulation. And based on ordering this filtered fringe modulation, a more optimized phase unwrapping path can be found out. The consequent phase unwrapping path is always along the direction from an area in which local spatial frequency is less further from the fundamental frequency to one in which local spatial frequency is more further from the fundamental frequency. The experiment shows that the new phase unwrapping algorithm is reasonable and effective. Even in the worse case the error is limited, if there is any, to local minimum areas.