ABSTRACT
A large class of image processing transformations is linear in nature; an output image is formed from linear combinations of pixels of an input image. Such transforms include convolutions, correlations, and unitary transforms. Applications of linear transfoims in image processing are numerous. Linear transforms have been utilized to enhance images and to extract various features from images. For example, the Fourier transform is used in highpass and lowpass filtering (Chapter 2) as well as in texture analysis. Another application is image coding in which bandwidth reduction is achieved by deleting lowmagnitude transform coefficients. In this chapter we provide some typical examples of linear transforms and their reformulations in the language of image algebra.
