Temporal demodulation of fringe patterns with sensitivity change

Natural Demodulation of 2D Fringe Patterns

For almost two decades one of the most successful methods of demodulating fringe patterns was based on the Fourier transform implementation of the 1-D Hilbert transform /1/ . Recently, however, a method of fringe analysis based on an isotropic 2-D Hilbert transform has been proposed /2/ . An isotropic Hilbert transform had been previously considered topologically impossible by many researchers....

Fringe Pattern Demodulation Using Evolutionary Algorithms

Adaptive asynchronous algorithm for fringe pattern demodulation.

We present a spatial adaptive asynchronous algorithm for fringe pattern demodulation. The proposed algorithm is based on the standard five-step asynchronous method with the one modification that we select the best sample spacing for each point of the fringe pattern. As we show, the frequency response of any asynchronous method depends on the sample spacing. This interesting behavior is used to ...

Natural demodulation of two-dimensional fringe patterns. I. General background of the spiral phase quadrature transform.

It is widely believed, in the areas of optics, image analysis, and visual perception, that the Hilbert transform does not extend naturally and isotropically beyond one dimension. In some areas of image analysis, this belief has restricted the application of the analytic signal concept to multiple dimensions. We show that, contrary to this view, there is a natural, isotropic, and elegant extensi...

A self-calibrating phase-shifting algorithm based on the natural demodulation of two-dimensional fringe patterns.

A new method of estimating the phase-shift between interferograms is introduced. The method is based on a recently introduced two-dimensional Fourier-Hilbert demodulation technique. Three or more interferogram frames in an arbitrary sequence are required. The first stage of the algorithm calculates frame differences to remove the fringe pattern offset; allowing increased fringe modulation. The ...