Reduction of speckle noise in digital holography

A fundamental problem in holography, as well optical as digital, is the presence of speckle noise in the reconstruction process. Many approaches have been carried out in order overcome such a problem, ranging from altering the spatial coherence (optical techniques) of the illumination to imaging processing techniques (digital techniques). This work shows the merged use of digital imaging techniques in order to reduce the speckle noise in digital reconstruction of optically recorded Fresnel's holograms. The proposed filtering techniques are illustrated with experimental results.