2-DIMENSIONAL PHASE-LOCKED LOOP DEMODULATION OF INTERFEROGRAMS

A new technique for continuous phase determination of an interferogram based on a digital phase locked loop is presented. The main advantage of this method, with respect to well established techniques such as F ourier or phase stepping demodulation, is that the traditional approac h to phase unwrapping processes by removal of discontinuities is not r equired. The phase is determined continuously as the phase locked loop scans the two-dimensional interferogram. Because of the sequential na ture of the algorithm proposed, this can be implemented using a specia l purpose video processor for phase determination at video rates. The above mentioned properties makes the presented technique a fast algori thm for phase determination of carrier frequency interferograms modula ted by a two-dimensional smooth phase function.