Formation of speckle images formed for diffusers illuminated by modulated apertures (circular obstruction)

Abstract

An amplitude modulation of circular aperture is used for the illumination of a numerical object having a randomly distributed function. In this study, a central obstruction for the aperture is assumed. The modulated speckle image is obtained using the MATLAB program and compared with that obtained in the case of an uniform circular aperture for the illumination. We have considered coherent illumination obtained from a laser beam in order to facilitate the computation of the Fourier transform of the defined computed speckle intensity corresponding to this novel aperture. Finally, the autocorrelation function of the randomly distributed object is calculated in all cases.