This paper proposes the use of a modified Morlet wavelet in order to demodulate fringe patterns in conjunction with the
one-dimensional continuous wavelet transform (1D-CWT). Our investigations demonstrate that the modified Morlet
wavelet produces better results compared to the conventional Morlet wavelet when used in fringe pattern analysis. This
novel technique offers superior performance in analysing fringe patterns from objects that exhibit large height variations.
This new technique has been used in conjunction with the direct maximum ridge extraction algorithm and an
improvement in performance is observed. The algorithm has been tested using both computer-generated and real fringe
patterns; and was found to be suitable for fringe pattern demodulation and robust in operation.
In this paper, we propose a novel three-dimensional phase unwrapping algorithm that extends the “two-dimensional phase unwrapping algorithm based on sorting by reliability following a non-continuous path” into three dimensions. The proposed algorithm depends on a quality map to unwrap the more reliable voxels first and the less reliable ones last. It follows a non-continuous path to perform the unwrapping process. Computer simulation has demonstrated that the proposed algorithm is more suitable than its two dimensional counterpart when used to unwrap volumetric data.
A digital phase locked loop (DPLL) algorithm has been applied successfully to demodulate continuous fringe patterns. An attempt was made by Ochoa et al. to extend the DPLL algorithm to demodulate non-continuous fringe patterns. Their algorithm depends on masking the invalid regions in a fringe pattern and exclude them from processing using the DPLL algorithm. Ochoa et al. have employed the standard deviation algorithm to mask the invalid regions and detect the regions with valid information. The algorithm failed in masking noisy invalid areas and detecting valid regions with low modulation indices. In this paper, a different method is used successfully in the masking of the invalid regions, detecting the valid areas and the method is applied to demodulate non-continuous fringe patterns using the DPLL algorithm.