Wavelet transforms and other multi-scale analysis functions have been used for compact signal and image representations in denoising, compression and feature detection processing problems for about twenty years. Numerous research works have proven that space-frequency and spacescale expansions with this family of analysis functions provided a very efficient framework for signal or image data.

-Wavelet transforms and other multi-scale analysis functions have been used for compact signal and image representations in denoising, compression and feature detection processing problems for about twenty years. Numerous research works have proven that　space-frequency and spacescale expansions with this family of analysis functions provided a very efficient framework for signal or image data.