Optimizing the Performance of Halftoning-Based Block Truncation Coding

Block Truncation Coding (BTC) is an effective lossy image coding technique that enjoys both high efficiency and low complexity especially when halftoning techniques are employed to shape the noise spectrum of its output. However, due to its block-based nature, blocking artifacts are commonly found in the coding outputs. Post-processing schemes are generally applied to soften the problem. Recently, a halftoning-based BTC algorithm was proposed to solve this problem by eliminating the cause of blocking artifacts. In this paper, through an optimization step, the performance of the algorithm is optimized in terms of a given objective measure. The idea can be adopted to work with other halftoning methods to optimize other measures for suiting different needs in different circumstances.