Skip to Main Content
Multi-resolution quad-tree based image representations are useful for image and video encoding at varying bit rates. Existing algorithms use a difference measure of color values to trim branches of the quad-tree, which results in the various spatial regions of the image being represented at different resolutions. However, color difference-based quad-tree branch pruning often leads to sub-optimal multi-resolution images, where interesting features of the image are represented at low resolution, and/or uninteresting image regions are represented at high resolution. In this paper, we present a mask-based method for pruning a quadtree representation of a multi-resolution image. The masks highlight various features of the image which require the best resolution, allowing tightly controlled pruning of the quad-tree branches. We suggest three main groups of masks, which are suitable for most types of applications requiring multi-resolution images and videos.