Digital video watermarking

The rapid growth of the digital technologies has introduced copyright protection problem for digital data and digital watermarking methods are proposed to solve it. A digital watermark is a secret message that is embedded to an original digital data with a secret key. The copyright owner proves his/her ownership by extracting the watermark from the digital data in the case of an illegal usage of the digital data. In this thesis, digital video watermarking methods were studied. Two different video watermarking methods, the discrete cosine transform based method and the discrete wavelet transform based method, are implemented. In addition, a hybrid method using both transforms together is developed and proposed in the thesis. The watermark is divided into pieces and each piece is embedded into frames of digital videos using secret keys and developed security algorithms. The performances of the three watermarking methods are compared with each other under several attacks such as frame dropping, frame averaging, noise addition, video compression, image enhancement and median filtering. A video watermarked by the hybrid method gains the power of the diversity of different ways of watermarking. This power grants an efficient and more accurate watermark reconstruction capability from a video undergone an attack from a large group of types. In the thesis, the proposed hybrid method is proved to be superior to the other methods.