A Review on Histogram Shifting for Reversible Watermarking Technique

As there is rapid growth in Internet technology, Information can be exchanged fastly and easily over web. This include images, videos, documents etc. This information needs to be protected, to protect this various techniques were developed. Reversible Watermarking is one of the technique to protect images of sensitive contents. In the field of watermarking lot of researches is taking place to establish more efficient reversible techniques. The existing system suffers from undesirable distortion which is unsuitable or less reliable. To improve the quality of the watermarked image a combination of two techniques pixel histogram shifting (PHS) and dynamic predictive error histogram shifting (DPEHS) are introduced. In this method the image is classified for finding watermark region and then watermark bits are applied by direct histogram shifting or by shifting it dynamically.