Edge-preserving image coding based on local modeling of images

A coding scheme which encodes each contiguous block of an image based on its local structure is developed. Three different types of models are constructed to characterize the image patterns occurring most frequently in a small block. The average bit rate is reduced by making use of the special constraint among the pixels in an oriented model, where the intensity variation is along only one direction. Judging from the image quality around edges, the reconstructed images with a bit rate less than 0.68 bit/pixel are perceptually superior to those obtained by the block and truncation coding at a bit rate of 1.64 bits/pixel. The complexity of this algorithm increases linearly with the size of the block and the number of orientations considered, which is much lower than that of the standard vector quantization techniques