Digital watermarking and data hiding

Digital watermarking is one of the proposed methods to prove the ownership and the authenticity of the media. Watermarking is the process that embeds data, such as a company logo or a signature, into a digital multimedia, such as a digital image or video. Distortion is introduced during the watermark embedding process. Although the distortion is normally small, for some applications, such as medical and military, do not allow permanent loss of signal fidelity. This highlights the need of lossless watermarking. Lossless watermarking is a watermarking technique which the original host image can be recovered perfectly after the watermark extraction. In this thesis, lossy watermarking and lossless watermarking algorithms are investigated. We can achieve different objectives, such as excellent JPEG resistibility, reduction in the Mean Square Error between the original image and the watermarked image or selection of embedding regions, by choosing different proposed algorithms with different types of input images. Moreover, apart from using watermarking to the prove the ownership of the media, we have noticed that watermarking and data hiding can be used in trans-coding, such as resizing, or error concealment. Side information can be embedded using watermarking or data hiding. Experimental results show that we can obtain better visual quality in resizing with the help of lossless data hiding techniques