Enhanced AMBTC based data hiding method using hamming distance and pixel value differencing

A Hybrid Data Hiding Method for Strict AMBTC Format Images with High-Fidelity

“…Therefore, the image quality of [28] is the best, but the hiding capacity is the lowest in most images. Our proposed method can achieve the second highest hiding capacity, i.e., only lower than [30]. In addition, our proposed method can achieve a relatively higher image quality.…”

“…where (m, n) denotes the coordinate of each pixel. Three relevant data hiding methods which embed data into AMBTC compressed images while preserving the final file size that were proposed by Ou and Sun [28], Chen and Chi [29], and Kumar et al [30] are used to compare with our proposed method. For a fair comparison, two thresholds are set to the same values in the four methods.…”

“…The error ratio is the ratio of the error blocks to all blocks, and the error blocks are blocks where two quantization values are exchanged. Our proposed method can embed 6 bits and 4 bits into one less complex block and one highly complex block, with 2 bits and 1 bit less than [30], respectively. Thus, the gap in hiding capacity between our proposed method and [30] decreases when thresholds are enlarged, and the hiding capacity of our proposed method is always higher than the remaining two methods.…”

“…In this section, we propose a data hiding method for AMBTC compressed images using a hybrid strategy to process different types of AMBTC compressed blocks that can maintain the strict AMBTC format. The proposed method also uses two thresholds to define three block types as done in [30]: smooth blocks, less complex blocks and highly complex blocks. Three strategies named bitmap replacement, matrix encoding, and symmetric quantization value embedding are then applied to embed data into the blocks of different types and no error blocks are generated after embedding.…”

“…Later, Chen and Chi [29] sub-divided complex blocks into less complex blocks and highly complex blocks, then used the method of [28] to process the smooth blocks and less complex blocks while embedding 2 bits into a highly complex block by changing the number of '1's in the bitmap to even or odd. Kumar et al [30] further improved the above methods by using the Hamming distance and pixel value differencing to embed 8 bits into a less complex block and 5 bits into a highly complex block, respectively. In the AMBTC compressed image, each block is strictly represented by a code (L, H, BM).…”