Image compression using optimal variable block truncation coding

We propose a variable block truncation coding with optimal quadtree segmentation (VBTC) to compress still images. Subject to a given bit budget, the best quadtree segmentation of an image is found for VBTC such that the distortion of the reconstructed image is minimal. Compared to the conventional variable BTC (vBTC) and hierarchical BTC (HBTC) at 1.425 bits per pixel (bpp), our proposed VBTC achieves 17.6% and 54.9% error reduction, respectively. A bit plane reduction scheme is also applied for obtaining lower bit rates. Our simulation results show that our proposed VBTC combined with bit plane reduction scheme is superior to VBTC, HBTC, and adaptive compression coding (ACC).