| Summary: | 碩士 === 國立中央大學 === 資訊工程研究所 === 94 === Watermarking is a technique to hide secret information in digital media. The information can prove ownership, identify a misappropriating person, trace the marked document’s dissemination through the network, or simply inform users about the rights holder or the permitted use of the media. Video watermarking introduces several issues which are not presented in image watermarking. Due to large amounts of data and inherent redundancy between video frames, video watermarking encounters many problems such as lost of watermark information, bad robustness, and etc.
In this paper, we proposed a video watermarking technique to protect multimedia data copyright by embedding a gray-level image as a watermark into a video. In the proposed method, a video is decomposed into several scenes; each scene consists of several image frames. The contextual energies of the video frame wavelet coefficients are computed to select embedding coefficients. The video frames are then embedded by watermarks in the larger-contextual energy wavelet coefficients.
The proposed video watermarking algorithm has the following advantages: (1) it allows blind retrieval of embedded watermark; that is, we need no original video to retrieve the watermarks; (2) the video image frames are converted to discrete wavelet transform (DWT), and embedded in DWT subbands makes watermarks perceptually invisible; (3) it is robust against the attack of frame dropping and scene dropping because of the watermark is embedded in each frames of the video; (4) it has higher imperceptible watermarked frames and more robust extracted watermarks by embedding watermarks in larger-contextual energy coefficients.
|
|---|
