Speckle Correlation Fringes Research Articles

Delinking of spurious translations in HI using speckle correlation technique

Presents a novel method to detect and delink spurious translation which may occur while doing stress analysis using hologram interferometry. The method is based on the fact that the Fourier transform of the transmittance function of the hologram gives speckle correlation fringes. The sensitivity and limitations of the method are also highlighted.

A simple tool for speckle-shearing interferometry

A common glass plate has been shown to be an adaptable and effective tool for use in speckle-shearing interferometry. Analyses of both the imaging system and the optical-filtering arrangement have been developed. Experiments were performed successfully. The results of these experiments have shown that visible speckle correlation fringes related to the derivatives of surface displacement are obtained when a common glass plate is used as a shearing component.

Contrast of speckle correlation fringes in presence of a longitudinal displacement between the two exposures

The visibility of speckle correlation fringes is studied in the case of a longitudinal displacement of the photographic plate between the two exposures. If the two speckle patterns are recorded at a large distance from the ground glass, the fringe visibility varies in the Fourier plane. It is high in the center and at the edge, and very low in the intermediate zone. The same experiment is repeated with the difference that the photographic plate is now quite near the ground glass. In this case the diameter of the central zone of high visibility fringes is related to the angular width of the Fourier spectrum of the ground glass.