1. In the process of changing spatial characteristics of a pixel defined image such as the magnification and minification of pixel defined images, a method of computing values for new pixels based on old pixel values of an image when the spatial characteristics of the image are changed, said method comprising the steps of establishing an equation for polynomial interpolation of a value of a new pixel based on values of a plurality of old pixels neighboring said new pixel, precalculating a plurality of sets of weighting coefficients for said old pixels based on said equation and on the relative location of a new pixel with respect to the old pixels, and applying a set of weighting coefficients to values of neighboring old pixels for each new pixel based on the relative location of each new pixel with respect to the old pixels.