Sampled-speckle photography for measurement of deformation

Opt Lett. 2000 Feb 15;25(4):218-20. doi: 10.1364/ol.25.000218.

Abstract

Speckles usually are of two kinds: laser speckle and white-light speckle. An additional kind, termed a sampled speckle, is proposed. Whereas laser speckles arise from multiple interference of light scattered from an object illuminated by a coherent laser beam and white-light speckles are a physically generated speckle pattern on the surface of the object, sampled speckles are generated as a result of the sampling of a digital image. The generation of these speckles and their application to displacement measurement are demonstrated.