Speckle Methods

Speckle methods are high-sensitivity non-contact optical methods for measuring displacements. They are based on the speckle effect. Speckles are granular dots that result from the illumination of a diffusively reflecting rough surface with coherent lightLightcoherent. The reflected or scattered wavelets interfere to create a random speckle pattern with statistical properties. The laser speckle is due to the coherenceCoherence of the light and the roughness of the surface of the order of the wavelengthWavelength of light.