Remote laser speckle interferometry: A speckle pattern formation model

A mathematical model of laser radiation scattering from a remote rough surface illuminated by a focused laser beam is proposed. The model can be used to estimate the mean number and size of speckles and their mean and maximum intensity. Fluctuations of the speckle intensity were observed upon focusing radiation in the object plane. The magnitude of fluctuations achieves 50% — 70% and depends on the object roughness and the laser beam parameters.