Hierarchical filtering of SAR images

In speckled radar images, filtering must achieve a tradeoff between smoothing of textural areas and edge preservation. Multiscale analysis splits up the image information content, such as edges and texture, according to a scale factor by successive lowpass and highpass filterings followed by downsampling. The speckle noise is present on each downsampled image. As proven by the wavelet theory, the initial image can be built again from these images without loss of information. This algorithm deals with a hierarchical weighted building procedure combined to a thresholding applied on high-frequency images.