Fringe-pattern demodulation using an iterative linear digital phase locked loop algorithm

✍ Scribed by Munther A. Gdeisat; David R. Burton; Michael J. Lalor

• Book ID: 103875046
• Publisher: Elsevier Science
• Year: 2005
• Tongue: English
• Weight: 399 KB
• Volume: 43
• Category: Article
• ISSN: 0143-8166
• DOI: 10.1016/j.optlaseng.2004.08.006

✦ Synopsis

A novel technique called an iterative linear digital phase locked loop (DPLL) for fringe-pattern demodulation is presented. The proposed technique has better noise immunity than the basic onedimensional DPLL algorithms (e.g., conventional and linear DPLLs) because it processes a fringe pattern in two dimensions. In the first iteration of the proposed algorithm, it uses a flat reference to estimate the phase of the fringe pattern. The estimated phase map resulting from the first iteration is smoothed using a moving average window and then it is used as a reference to estimate the phase of the fringe pattern in the second iteration. In the third iteration, the phase map resulting from the second iteration is smoothed and used as a reference to estimate the phase of the fringe pattern in the fourth iteration and so on until the demodulated phase map has a good signal-to-noise ratio.