Catherine Wykes

Use Of Electronic Speckle Pattern Interferometry (ESPI) In The Measurement Of Static And Dynamic Surface Displacements

Electronic speckle pattern interferometry (ESPI) enables static and dynamic surface displacements to be measured in real time to an accuracy of the order of a wavelength of light. The principles of the technique are outlined and the different configurations of interferometers described. Some applications of the technique are discussed.

De-correlation Effects in Speckle-pattern Interferometry. 1. Wavelength change dependent de-correlation with application to contouring and surface roughness measurement

A theoretical investigation of the de-correlation of speckle pattern with change of wavelength has been performed with particular reference to the electronic speckle-pattern interferometer. A method of measuring surface roughness using speckle de-correlation is proposed and some preliminary results presented. In addition, the loss of fringe visibility in two-wavelength speckle-pattern interferometric contouring is investigated and experimental confirmation of the theory given.