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.