標題: | 音訊展頻浮水印檢測與解碼之研究 Detection and Decoding of Audio Spread-Spectrum Watermarking |
作者: | 李維晟 Wei-Cheng Lee 張文輝 Wen-Whei Chang 電信工程研究所 |
關鍵字: | 音訊;浮水印;離散餘弦轉換;展頻調變;聲響心理分析;廣義高斯分布;Audio;Watermarking;Discrete cosine transform;spread-spectrum modulation;psychoacoustic model analysis;generalized Gaussian distribution |
公開日期: | 2003 |
摘要: | 由於網際網路的廣泛應用及影音壓縮技術的躍進,使得盜版傳播的問題日益嚴重,為保障原創者之智慧財產,在多媒體檔案中隱藏認證資訊有其必要性。最佳之浮水印設計必須兼顧隱密性、強軔度及可靠度,隱密性使其不被盜版者察覺,強軔度使之能對抗惡意破壞,而可靠度能減少誤警情況的發生。我們採用離散餘弦轉換配合直序展頻技術來建構嵌入浮水印之函數,主要之關鍵在於設定一離散餘弦係數之廣義高斯機率模型,再根據最大相似度理論,設計最佳的檢測與解碼機制。除此之外,我們也探討非特定機率模型的一般情況,並推導出相關之檢測與解碼演算法。 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. |
URI: | http://140.113.39.130/cdrfb3/record/nctu/#GT009113545 http://hdl.handle.net/11536/46323 |
顯示於類別: | 畢業論文 |