Extending steganography payload capacity using the L*a*b* color space

The traditional trade-off between payload capacity and stego quality of steganographic information systems has kept hiding capacities at relatively low values due to the adverse effect on stego quality. This paper proposes a new strategy that can raise the hiding capacity without negatively impacting stego quality. The proposed scheme exploits a concept derived from the Human Visual System (HVS) which indicates that the sensitivity of human perception is markedly lower in the chrominance channels of an image as compared to the luminance channel. Thus, this new scheme proposes to hide in the L*a*b* color space rather than the RGB color space for higher capacity rates. This is due to the fact that the L*a*b* color transformation has the ability of separating chrominance from luminance information for a given color image. Experimental results demonstrate that the proposed scheme is able to show advantages over traditional RGB schemes in hiding capacity as well as stego quality.