Detection and Decoding of Audio Spread-Spectrum Watermarking

• Main Authors: Wei-Cheng Lee, 李維晟
• Other Authors: Wen-Whei Chang
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/tp6qxt

碩士 === 國立交通大學 === 電信工程系所 === 92 === In this thesis, we address the problem of the performance analysis of audio watermarking systems that use a spread spectrum technique in the discrete cosine transform (DCT) domain. Two tests are involved in the ownership verification process. First, a watermark detector decides whether the audio under test contains a watermark generated with a certain key. If the audio is watermarked , then authorship by the key holder is proved and extraction of hidden message can be performed by a detector. Most current research concentrate on correlation detectors, despite evidence showing that the underlying Gaussian model assumption does not match the intrinsic natures of DCT coefficients. Recognizing this, we first investigate a statistical approach that uses the generalized Gaussian probability to characterize the DCT coefficients and then use it as a basis for the application of statistical decision theory to the design of efficient detector and decoder structures. We also generalize this approach to the possible nonexistence of a statistical description of the original audio.