The use of a second-order digital phase-locked loop (DPLL) to demodulate fringe patterns is presented. The second-order DPLL has better tracking ability and more noise immunity than the first-order loop. Consequently, the second-order DPLL is capable of demodulating a wider range of fringe patterns than the first-order DPLL. A basic analysis of the first- and the second-order loops is given, and a performance comparison between the first- and the second-order DPLL’s in analyzing fringe patterns is presented. The implementation of the second-order loop in real time on a commercial parallel image processing system is described. Fringe patterns are grabbed and processed, and the resultant phase maps are displayed concurrently.
© 2000 Optical Society of America
Original Manuscript: January 6, 2000
Revised Manuscript: June 22, 2000
Published: October 10, 2000
Munther A. Gdeisat, David R. Burton, and Michael J. Lalor, "Real-time fringe pattern demodulation with a second-order digital phase-locked loop," Appl. Opt. 39, 5326-5336 (2000)