Fringe interpretation for hologram interferometry of rigid-body motions and homogeneous deformations

Previous theoretical work on hologram interferometry is reduced, in this paper, to a number of guide lines for fringe interpretation. One of the most helpful is that, for any combination of rigid-body motion and homogeneous deformation, fringes appear on the object as though it intersected a set of equally spaced lamina perpendicular to a specific fringe vector. This elucidates the role that object shape plays in determining fringe patterns. Fringe localization for slit-apertured optical systems and fringe parallax are compared and the conditions for their equivalence are presented. The line of fringe localization that results from observation with a large two-dimensional aperture in an optical system is shown to have a simple geometrical relationship to the axis of the helical motion that may characterize any rigid-body motion. The orientation of fringes in their region of localization can be used to differentiate between rigid-body motions and some homogeneous deformations.