Numerical model for simulation of dynamic speckle reference patterns

We propose a numerical model to describe dynamic speckle phenomena. It includes free space propagation, focused and defocused image situations and the effect of the illuminating wavefront phase. We test the model by verifying its statistics and using the results of Okamoto and Asakura for the pure translational, pure boiling and mixed cases of dynamic speckle obtained by moving a rigid diffuser: and also the results of Briers for a plane with a mix of static and moving scatterers. The difficulties associated with the discretization process of the Fresnel propagation formula are analyzed. The model was also compared with controlled experiments and the results suggest that it could be used as a reference to test the performance of activity measurement algorithms under controlled conditions. Three dynamic speckle activity descriptors were also evaluated and compared in boiling speckle simulations: Laser Speckle Contrast Analysis (LASCA), Generalized Differences and Energy of Spectral Bands. (c) 2009 Elsevier B.V. All rights reserved.