Abstract :
In this Project, we present a reversible data hiding scheme based on histogram modification. We exploit a binary tree structure to solve the problem of communicating pairs of peak points. Distribution of pixel differences is used to achieve large hiding capacity while keeping the distortion low. We also adopt a histogram shifting technique to prevent overflow and underflow. Performance comparisons with other existing schemes are provided to demonstrate the superiority of the proposed scheme.
The digital watermarking system essentially consists of a watermark embedder and a watermark detector (see Figure). The watermark embedder inserts a watermark onto the cover signal and the watermark detector detects the presence of watermark signal. Note that an entity called watermark key is used during the process of embedding and detecting watermarks. The watermark key has a one-to-one correspondence with Watermark signal (i.e., a unique watermark key exists for every watermark signal). The watermark key is private and known to only authorized parties and it ensures that only authorized parties can detect the watermark. Further, note that the communication channel can be noisy and hostile (i.e., prone to security attacks) and hence the digital watermarking techniques should be resilient to both noise and security attacks. In the past decade the use of digital data has been increased significantly. The advantages of digital data are that easily be transmitted, carried, stored. The most crucial disadvantages are the copying and copyright issues. Copyright is the exclusive right to copy. The owner of the copyright has the right to exclude any other person from reproducing the product or using the work covered by copyright for a specific period of time.