Measurement of axial motion by multiple exposure speckle photography: use of uncollimated beam illumination in free space geometry.
A theory has been developed showing the effect of multiple exposures on the fringes formed in the case of axial motion of a diffuser illuminated by a diverging beam from a laser point source. Experimental conditions are such that the speckle patterns remain fully correlated. Filtering has been done by the converging beam. Fringe profiles, in the case of multiple exposures, have been investigated for unequal and equal exposure times, and good agreement was found between theoretical and experimental results.
Kumar
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Singh
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