Study and Implementation of Watermarking Algorithms

Water Making is the process of embedding data called a watermark into a multimedia object such that watermark can be detected or extracted later to make an assertion about the object. The object may be an audio, image or video. A copy of a digital image is identical to the original. This has in many instances, led to the use of digital content with malicious intent. One way to protect multimedia data against illegal recording and retransmission is to embed a signal, called digital signature or copyright label or watermark that authenticates the owner of the data. Data hiding, schemes to embed secondary data in digital media, have made considerable progress in recent years and attracted attention from both academia and industry. Techniques have been proposed for a variety of applications, including ownership protection, authentication and access control. Imperceptibility, robustness against moderate processing such as compression, and the ability to hide many bits are the basic but rat..

Overlapping pixel value ordering predictor for high-capacity reversible data hiding

In recent years, many reversible information hiding methods have been proposed. Among them, the pixel value ordering (PVO) method can be used to create high-fidelity camouflage images under good embedding capacity. The original PVO method adopted the block-by-block manner, and each block could embed only 2 bits. In this study, we propose an overlapping PVO (OPVO) method. In the PPVO method, secret data are embedded in the maximum and minimum pixel values to improve the situation in which only up to 1 bit can be embedded in a sliding window. In the pixel-by-pixel manner, each pixel can embed data multiple times. We make full use of the correlation between adjacent pixels in the natural image to increase the embedding capacity. An advantage of the overlapping PVO method is that its embedding capacity is more than twice as high as that of previous PVO series methods where an acceptable image quality is maintained. In our experiment, the embedding capacity of the smooth image is up to 130,000 bits, whereas that of the complex image is higher. However, the image quality decrease rate of the proposed method tends to be lower than that of the other methods. Therefore, any kind of image is suitable for our method