Noncontact measurement of object normal vibrations using the theory of speckle decorrelation

This paper builds on the general theory of determination of the small deformation tensor by means of the method availing the statistical properties of speckle pattern propagating through free-space and image-field[1], [2], [3]. It concentrates on vibrations determination in the direction of the normal to the object surface plane. In the first part of this paper the basic theoretical equations are mentioned, next some experimental configurations are designed for the measurement of the normal vibrations of an investigated object with a rough surface, finally the analysis of sensitivity and accuracy is done and some experimental results are also presented.