METHOD OF FILTERING IMAGES USING IMAGE COMPRESSIBILITY TO DETERMINE THRESHOLD PARAMETER

A method of filtering an image to reduce noise. The image is divided into subimages or "blocks". An optimum value of a threshold parameter is determined by repeatedly applying a Singular Value Decomposition ("SVD") transform to one of the blocks for various values of the threshold parameter and then using a lossless compression algorithm to determine the compressed size of the various transforms. The optimum threshold parameter is determined by finding the maximum of the second derivative of the compressed size with respect to the log of the threshold parameter. The SVD transform is then applied to all the blocks using the optimum value of the threshold parameter, and the transformed blocks are then recombined to provide the filtered image.