Uniform frequency images: adding geometry to images to produce space-efficient textures
Adam B. Hunter, Jonathan D. Cohen · 2000
: We discuss the concept of uniform frequency images, which exhibit uniform local frequency properties. Such images make optimal use of space when sampled close to their Nyquist limit. A warping function may be applied to an arbitrary image to redistribute its local frequency content, reducing its highest frequencies and increasing its lowest frequencies in order to approach this uniform frequency ideal. The warped image may then be downsampled according to its new, reduced Nyquist limit, thereby reducing its storage requirements. To reconstruct the original image, the inverse warp is applied. We present a general, top-down algorithm to automatically generate a piecewise-linear warping function with this frequency balancing property for a given input image. The image size is reduced by applying the warp and then downsampling. We store this warped, downsampled image plus a small number of polygons with texture coordinates to describe the inverse warp. The original image is later recon...