A technique of white-light color encoding of misfocused speckle interferometric fringe patterns is presented. The encoding is performed in the spatial frequency plane with color filters. This technique allows the viewing of a multiset of encoded speckle interferograms simultaneously. Thus, it may provide new informational interferometric aspects of the object under stress or vibration. The effect on the speckle fringe pattern due to the spatial filtering is briefly discussed, and experimental demonstrations of color encoded fringe patterns are presented. Due to the simplicity and versatility of the processing technique, we feel that the technique may develop into a practical tool for strain, stress, and vibrational measurement.
F. T. S. Yu,
P. H. Ruterbusch,
"White-Light Optical Processing Of Misfocused Speckle Interferograms," Optical Engineering 22(1), 221156 (1 February 1983). https://doi.org/10.1117/12.7973066