Capacity control of reversible watermarking by two-thresholds embedding

The distortion introduced by the watermarking depends on the embedded capacity. For the difference expansion reversible watermarking, the classical threshold control does not ensure a fine tuning of the embedding capacity and the simple partial embedding can introduce artifacts. This paper proposes the fine tuning of the capacity by splitting the image into two parts and by marking them with consecutive threshold values. Intermediate capacity values between the ones provided by the thresholds are obtained by varying the ratio between the two parts. The method ensures a fine control of the capacity without introducing artifacts. Experimental results are provided.