Audio And Video Digital Watermark

The technology of information and digital products have been widely used as the rapid development of information and communication science. The usage and spread of digital products are advanced by computer and internet techniques. Meanwhile, the need of copyright protection and information security, which is the background of digital watermark, becomes more and more important. Digital watermarks protect the information and copyright of digital products by embedding information in medias. This technology is also used in other fields such as medicine, law evidence, and ticket fake-pretending.The work of the paper mainly covers:A new quantization target, the difference of the sum of the odd and the even coefficients in digital wavelet transforms (DWT ) domain, was present. It makes the watermarks embedding distortion attribute to the even coefficients, effectively improving signal noise rate (SNR) after watermarks embedding.A robust-fragile combination detection was shown, indicating good dual watermarks features for copyright protection and authentication of the algorithm above. Experiments results show that SNR is better than the traditional quantization algorithms given similar complexity.A video digital watermark algorithm basing on the statistical property of video block energy is proposed. The stability of block energy and the statistical base make the video watermark more robust to re-coding attacks, which is shown in experiments.