Orthonormal sets of filters obtained by modulations and rotations of a prototype

Summary form only given. In the past decade the field of image processing has grown considerably, and although various successful techniques have been developed for tasks such as image compression, understanding and segmentation, one final piece is missing. Bearing in mind that ultimately, an image is evaluated by a human observer, it is obvious that the usual mean-square error is not appropriate and thus we still sorely lack subjective measures of image quality. Some physiological results point out that the early stage of the human visual system (HVS) works like a filter bank on the retinal image. The filters in such a filter bank can be seen as being obtained by rotation and modulation from an original prototype filter. This work is just the first step and concentrates on the design of local bases obtained by unitary transformations of a single (or more than one) prototype filter.