masking theory 中文意思是什麼
masking theory
解釋
遮掩學說-
But, though considerable process has been made in the last ten years, digital watermarking is still in its infancy, and much interesting work remains to be done this thesis addresses some problems in the gray - scale image digital watermarking that are summarized below : 1 ) whereas the basic theory of digital watermarking is still very poor, a digital watermarking mathematic model based on imperceptibility and robustness is presented by analysising the characteristic of digital watermarking ; 2 ) based on the model constructed above, by defining the measures of capacity and robustness of digital watermarking, an objective method for evaluating the digital watermarking is introduced and used to analysis some algorithms ; 3 ) whereas geometric distortion always influences the restoration of watermark, we advocate to enhance the robustness against geometric distortion by restoring the image which has been distorted by geometric transformation, and a method is designed for estimating the parameters of geometric transformation ; 4 ) based on the conclusion discussed above, and combined with the masking effects of hvs, a novel public meaningful gray - scale image digital watermarking is designed by analysising the characteristics of image gray - scale interpolation and haar wavelet transformation. the experimental results show that the method is indeed powerful ; 5 ) whereas many image digital watermarking schemes, which embed watermark by modifying the values of pixels in spatial domain and transformed domain, are confronted with the conflict between the imperceptibility and robustness, we advocated to use some stable digital characteristics of host image as watermark and a algorithm based on hermite matrix is designed
本文重點對灰度圖象數字水印技術進行研究，主要工作如下： 1 ）鑒于目前數字水印的理論研究比較薄弱的現狀，本文通過分析數字水印的特點，建立了一個數字水印的數學模型，為進一步研究數字水印打下了基礎； 2 ）根據以上建立的模型，通過引入容量和穩健度的概念為數字水印提供了一個客觀評價方法，並對一些數字水印演算法進行了分析； 3 ）為增強數字水印抵抗幾何攻擊的能力，研究了受幾何攻擊的圖象的復原問題，並給出了一個計算圖象幾何變換參數的方法； 4 ）通過分析圖象灰度插值演算法和haar小波變換的特點，結合hvs的掩蔽效應，設計了一個公開的有意義數字水印演算法，實驗結果表明本演算法具有較強的穩健性； 5 ）目前許多水印演算法都是通過在空域或頻域修改象素值的方法嵌入水印的，這種方法面臨著透明性和穩健性的矛盾，為解決這個矛盾，本文提出以圖象的某些穩定的數字特徵為水印的觀點，並結合hermite矩陣的特點設計了相應的水印演算法，實驗結果表明該演算法具有較好的穩健性。 -
This paper utilizes masking rate theory to analyze the variation of center zero - level energy, the influence of metallic mesh ’ s different parameters on infrared transmitting ; deduces the relational expression between infrared transmitting efficiency and metallic mesh ’ s parameters ; comes to the conclusion that we can improve infrared transmitting efficiency by increasing
理論研究表明，金屬網柵的周期選擇在200 ~ 400 m之間，線寬不大於10 m ，是較為理想的網柵參數。最後，在實驗室里用1 ~ 20ghz的信號發生器、功率放大器和頻譜分析儀等雷達波檢測設備，對金屬網柵的屏蔽效率進行測試。 -
Based on characteristics of human visual system ( hvs ), including texture / contract masking property and sensitivity of frequency, and combining with wavelet multi - resolution theory, a novel just noticeable difference ( jnd ) model that can embed watermark adaptively is proposed
用該模型可使指紋特徵信息生成的數字水印自適應嵌入合成的指紋圖像中，提高了指紋認證系統的可信度。
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