Embedding capacities of steganographic information security systems have remained relatively low due to the adverse effect on perceptibility, where researchers had to trade-off between higher capacities and reduced perceptual quality or choose higher perceptual quality albeit at the expense of lower capacities. This paper proposes a novel approach for color image steganography, in the discrete cosine transform (DCT) domain, that promotes optimal embedding capacity while improving stego image quality. The proposed approach is based on the observation that the space reserved for embedding the secret data varies with the statistical characteristics of the cover image and exploits a quad-tree adaptive-region embedding scheme to individuate “good” cover image segments, in relation to the correlation of pixels, for embedding the secret information. We will demonstrate that our scheme exhibits enhanced hiding capacity and perceptibility in comparison to techniques adopting fixed-block-size adaptive-regions in the DCT domain.
['Tamer Rabie', 'Ibrahim Kamel']
Toward optimal embedding capacity for transform domain steganography: a quad-tree adaptive-region approach