On the reconstruction of quadtree data

Image compression schemes consist of compression and decompression phases. Often, the decompression phase includes mechanisms for improving the quality of the resulting image. Quadtree compression is one such type of compression. Reconstructed quadtree images can be blocky because of the nature of the compression method, unless additional processing, generally smoothing, is performed. We propose improvements over the reconstruction method described by Shusterman and Feder (see ibid., vol.3, p.207-15, 1994). The improvements consist of the introduction of a simpler and more effective 2/spl times/2 reconstruction filter to replace the suggested 3/spl times/3 filter, and the addition of a reconstruction threshold to preserve image edges. This method is compared experimentally to the original algorithm and also to JPEG compression in terms of complexity and resulting image quality.