Reversible watermarking without underflow and overflow problems

Reversible watermarking, a technique that can recover an undistorted original image from a watermarked one, has drawn considerable attention in recent years. However, most of the current reversible watermarking algorithms based on histogram shifting have underflow and overflow problems in regards to the watermarked image due to the histogram shift. In order to nip these problems in the bud, in the proposed algorithm the lower and upper bound pixel levels are modified into the nearest neighbor pixel levels and the position information of the modified pixel levels are embedded in the watermarked image. In addition, to increase the data hiding capacity while keeping high visual quality of the watermarked image we allows multi-level data hiding using a rotated even-odd difference image. The simulation results demonstrate that the proposed algorithm generates a superior performance in the PSNR values and the embedding capacity.