Multiresolution de-speckle based on Laplacian pyramids

A multiresolution filtering procedure is derived from the framework of Laplacian pyramids and proposed for edge-preserving MMSE smoothing of images affected by multiplicative noise with speckle statistics. The basic idea of the novel scheme is to apply an MMSE filter (e.g., Kuan´s filter) to the different resolution layers in which the noisy image is decomposed. A noise-free image version is achieved by recombining the layers of the pyramid, once they have been filtered. Comparison tests performed on images affected by synthetic speckle, with both one-look and multi-look statistics, show significant SNR improvements over the basic Kuan´s scheme, resulting in far lower distortion between noise-free and processed images. Visual comparisons on true and simulated SAR images corroborate the objective results