HOLOGRAPHIC ILLUMINATION FOR COMPARATIVE MEASUREMENT

The displacement, the shape of an object, or the refractive index dist ribution change in the case of transparent objects can successfully be measured by either holographic or speckle techniques. However, the de mand for comparative measurements of two objects, e.g. master and test by interferometry has both conceptual and practical importance. One w ay of doing that is using holographic illumination for the test object . Applying holographic technique in recording test interferograms prov ides high resolution of records. On the other hand, the holographicall y illuminated test object may also be inspected by electronic speckle pattern interferometry more easily but with different quality. The pap er presents results of applications of hologram interferometric and el ectronic speckle correlation techniques in recording process of the di fference patterns showing that both techniques can be effective in com parative measurements of displacements.