Determination of Deformation Fields of Diffuse Objects by Phase-Shifting Digital Holographic Interferometry

Abstract

A modification of the method of digital holographic interferometry for the determination of deformations of an object with a diffuse surface by comparing two complex wavefronts reflected from the object at its two different states is considered. The difference of the proposed method with classical digital holography methods is that digital holograms by which the images are reconstructed have complex values determined by the phase shift method (‘‘complex’’ hologram), while classical digital holograms have only real values. Besides, digital holograms are reconstructed with allowance for inhomogeneity of the reference beam, which improves the reconstruction quality. For this purpose, a tunable neutral optical filter is introduced into the reference arm of the optical scheme of the interferometer. The method is verified experimentally.