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JPEG 2000 coding of color-quantized images

The efficiency of compressing color-quantized images using general purpose lossless image coding methods depends on the degree of smoothness of the index images. A well-known and very effective approach for increasing smoothness relies on palette reordering techniques. In this paper, we show that these reordering methods may leave some room for further improvements in the compression performance. More precisely, we provide experimental results showing that the JPEG 2000 lossless compression of palette reordered color-quantized natural images can be further improved if histogram packing is applied on a regional basis.