A new steganographic algorithm for color images (MPSteg-color) is presented based on Matching Pursuit (MP) decomposition of the host image. With respect to previous works operating in the MP domain, the availability of three color bands is exploited to avoid the instability of the decomposition path and to randomize it for enhanced security. A selection and an update rule working entirely in the integer domain have been developed to improve the capacity of the stego channel and limit the computational complexity of the embedder. The system performance are boosted by applying the Matrix Embedding (ME) principle possibly coupled with a Wet Paper Coding approach to avoid ambiguities in stego-channel selection. The experimental comparison of the new scheme with a state-of-the-art algorithm applying the ME principle directly in the pixel domain reveals that, despite the lower PSNR achieved by MPSteg-color, a classical steganalyzer finds it more difficult to detect the MP-stego messages.
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