Robust techniques for hiding data in images and video.

摘要

In this thesis we present a study and development of robust techniques for hiding data in images and video. In recent years, the internet and the world wide web have revolutionalized the way in which digital data is distributed. The widespread and easy access to multimedia content has motivated development of technologies for digital steganography or data hiding. Much of the recent work in data hiding is about copyright protection and authentication of multimedia data. Such digital watermarking typically require very few bits, and the objectives include robustness to attacks on the data. On the other hand, the primary goal of the research presented here is to develop techniques for hiding large amounts of multimedia data such as text, images, audio, and video, in images and video. In developing these techniques, emphasis is on robustness to signal compression as it is one of the mostly frequently performed signal processing operation on the data.; The thesis presents new techniques for such data embedding using well known transforms such as the Discrete Cosine Transform (DCT) and the Discrete Wavelet Transform (DWT). We utilize spread spectrum embedding and lattice encoding to hide signature data that is as much as 25% of the host data size. The signature data can be gray scale or color images or video sequences or audio data. The host signals explored include images and video. We demonstrate robustness to JPEG and MPEG compression that include both lossless and lossy hidden data recovery. We present methods that do not need the original host data for signature signal recovery.; The work presented here significantly advances the state of the art in multimedia data hiding, and has the potential of creating a whole new domain of applications including embedded control of multimedia data, smart multimedia objects, and video/audio quality control.