Reversible Medical Image Watermarking Technique Based on Choosing Threshold Values in Histogram Shifting

Reversible watermarking is an information hiding method, this technique retrieves the original image and the message perfectly. That is a useful tool for some specific applications such as: medical and military image systems. In this paper, a method which limits the range of threshold values is proposed. Instead of brute-force searching all threshold values in HPS method or choosing threshold values unsystematically. This method classifies and chooses a number of thresholds whose frequencies satisfy the vital capacity to gain the best imperceptibility. In addition, the proposed method puts forward a secure way of watermark. The results of the experiment on natural images and medical images show the method meets the imperceptibility and high capacity.