Nonseparable qmf pyramids

It is widely recognized that effective image processing and machine vision must involve the use of information at multiple scales, and that models of human vision must be multi-scale as well. The most commonly used image representations are linear transforms, in which an image is decomposed into a sum of elementary basis functions. Besides being well understood, linear transformations which can be expressed in terms of convolutions provide a useful model of early processing in the human visual system. The following properties are valuable for linear transforms that are to be used in image processing and vision modelling:.