Improved Adaptive-Edge method by changing the readjusting phase

The original Adaptive-Edge method proposed by Yang et al. is a novel adaptive least significant bit steganographic method that provides a larger embedding capacity and imperceptible stego images. In this paper, we propose an improved version of Adaptive-Edge method by changing the readjusting phase. The original readjusting phase is just executed for the pixel pairs whose difference values belong to different levels, before and after embedding. The new readjusting phase will be executed for every pixel pair, regardless of whether difference values belong to different levels or not. For each pixel pair, by fully exploiting the modification direction, one can thus select the best choice that introduces the smallest distortion. Experimental results show that the improved Adaptive-Edge method can provide better image quality when concealing with the same embedding capacity.