Distortion Control Reversible Watermarking

This paper continues our researches on reversible watermarking. The main contribution of this paper is the investigation of image distortion control methods. Two methods are proposed. The first one does not modify pixels which generate an error greater than a predefined threshold. Tuning the error, the image quality versus the hiding capacity is controlled. The second method limits the maximum error by watermarking only a slice of the image, namely 7 or 6 bits out of 8. The second method is not as flexible as the first one, but is of extremely low mathematical complexity. The methods are of interest in watermarking applications (image authentication and/or data hiding) where not only the original image must be exactly recovered at detection, but also the imperceptibility of the watermarking must be ensured.