Fringe pattern analysis

Abstract

 Fringe analysis techniques are very popular to estimate with reasonable accuracy physical quantities such as shape of objects, deformation, refractive index and temperature fields. They achieve these goals by recovering the local phase from one or a collection of interference fringe pattern images. The mathematical model of a fringe pattern is described by the equation

u=a+bcos(ψ+φ)

where a is the background illumination, b is the amplitude modulation, ψ is the spatial carrier frequency and φ is the phase map to be recovered. The problem of recovering not only φ but also a and b from the above equation is an ill-posed problem. Recently, variational techniques that aim to reduce uncertainty of the solution by introducing more information into the model by means of regularization of the unknown variables have proved to deliver a feasible solution to this problem. 

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