Grayscale image coding using optimal pixel grouping and adaptive multi-grouping division block truncation coding

An efficient grayscale image coding scheme based on block truncation coding (BTC) is proposed. The optimal pixel grouping mechanism and the multi-grouping division process are employed in the proposed scheme. An entropy-based indicator generation mechanism is employed to generate the block indicators of different groups. In addition, an optional bit rate reduction mechanism for dynamic block division is designed. Simulation results verify that significant image quality gain is acquired by the proposed scheme compared to the state-of-art image coding methods based on BTC. Meanwhile, a lower bit rate is consumed by the proposed scheme.