Micrometer-scale rigid-body translations are determined fromelectronic speckle interferometric fringe patterns. An iterativeminimum error procedure employs the relative fringe order of pickedpositions of fringe maxima and minima within a single interferogram tocalculate the displacement field directly. The method does notcalculate the displacement at a single point but relies on theassumption that the character, but not the magnitudes or directions, ofthe displacements over the viewing area of the interferogram isknown. That is, a model of the displacements exists. Onperfect, noise-free forward modeled fringe patterns calculated for an 8.0-μm displacement, the phase error is less than 2 ×10−6 fringe orders (1.3 × 10−5 rad)and probably results only from numerical noise in the inversion. Onreal fringe patterns obtained in electronic speckle interferometricexperiments, mean phase errors are generally less than 5 ×10−5 fringe orders (3.2 × 10−4rad), suggesting that the technique is robust despite errorsresulting from speckle noise, lack of accuracy in positioning ofexperimental components, and image-distortion corrections.
© 1998 Optical Society of America
(090.0090) Holography : Holography
(100.0100) Image processing : Image processing
(120.2650) Instrumentation, measurement, and metrology : Fringe analysis
(120.3180) Instrumentation, measurement, and metrology : Interferometry
Douglas R. Schmitt and R. W. Hunt, "Model-Based Inversion of Speckle Interferometer Fringe Patterns," Appl. Opt. 37, 2573-2578 (1998)