Improved transforms for the compression of color and multispectral images

In the compression of color or multispectral imagery, intra pixel color transforms are usually employed to decorrelate planes. It is usually thought that plane decorrelation (such as provided by the Karhunen-Love transform (KLT)) may lead to higher compression. Spatial correlation, however, is usually not considered. We developed a method to devise a pixel-wise color transform that takes into account spatial correlation and outperforms the KLT. This is done by considering space-color correlation. We aim at decorrelating the data across color planes, but at correlating the data spatially, so that spatial transforms can more easily decorrelate each of the color planes. Experiment results are shown to demonstrate the gains of the propose transform.