Reconstruction of an axisymmetric refractive index distribution using speckle photography

An application of speckle photography to determine the temperature distribution in an axisymmetric hot water jet is reported. The method is based on the analysis of two speckle patterns recorded in the same photographic film. Each pattern is produced by the interference of coherent light scattered by a ground glass. Refraction by the transparent object during one exposure brings about speckle displacements, from which input data for the reconstruction algorithm are obtained. Interchanging the relative location of diffuser and object with respect to the light source gives rise to two variations of the technique. Results procured using both alternatives are here presented and compared.

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