Theory of speckle displacement and decorrelation and its application in mechanics

The paper deals with the determination of tensor of the so-called small deformation of an elementary area of an object surface by means of an optical experimental method, which makes use of properties of the speckle field in an optically free space or in an image field. The term "small deformation tensor" is introduced and a relationship between a small deformation tensor of surface and a speckle field in free space or image field is analyzed.