Temporal Phase Unwrapping in Structured Perfilometry

摘要

In the perfilometry by means of structured light there are two techniques that are the most used: fringe projection and Moiré. The reconstruction of the object surface with inherently discontinuous or prominent slopings, is usually a difficult problem by using standard phase unwrapping technique i.e. the spatial unwrapping. The alternative of spatial correction by means of an optimum trajectory appears as a viable alternative in order to confront those inconvenient, where a phase unwrapping algorithm based on parameters of reliability can be used. Nevertheless, the processing time is high if many parameters of reliability are considered. To overcome this difficulty Huntley and Saldner proposed the temporal phase unwrapping procedure (TPUP) for the 3D surface reconstruction, and Peng X. et al., based on their work proposed an enhanced recursive scheme for the TPUP. The basic idea of the methods is that each pixel is measured as a time function. Unwrapping is carried out in the time axis for each pixel independent from the others. Edges and regions with a poor signal to noise reason will not have influence over the data of neighboring pixels. However the phase jumps no necessarily correspond to multiples of 2pi exactly. Due to this, in this paper an enhanced scheme for temporal unwrapping in order to increase its efficiency is introduced. Additional, we present some results obtained by mean of temporal unwrapping and spatial unwrapping, in order to compare them and to demonstrate the effectiveness of the modified temporal unwrapping.