Single bitmap block truncation coding of color images using hill climbing algorithm

In order to generate an efficient common bitmap in single bitmap block truncation coding(SBBTC) of color images, an improved SBBTC scheme based on weighted plane(W-plane) method and hill climbing algorithm is proposed. Firstly, the incoming color image is partitioned into non-overlapping blocks and each block is encoded using the W-plane method to get an initial common bitmap and quantization values. Then, the hill climbing algorithm is applied to optimize an initial common bitmap and generate a near-optimized common bitmap. Finally, the quantization values are recalculated by the near-optimized common bitmap and the considered color image is reconstructed block by block through the common bitmap and the new quantization values. Since the processing of each image block in SBBTC is independent and identical, parallel computing is applied to reduce the time consumption of this scheme. The simulation results show that the proposed scheme has better visual quality and time consumption than those of the reference SBBTC schemes.