imperceptibility 中文意思是什麼

Theoretical expatiate on general concepts and fundamental principles of information hiding and steganography, also point out possible directions for further research, also analysis the probability of speech as the host carry signal and efficient masking characteristics of psycho - acoustic model, it is shown that : there is an improvement on imperceptibility according to human auditory masking effect

闡述了信息隱藏技術和隱寫技術的重要概念、基本理論以及廣闊的應用前景。分析了將語音信號作為宿主載體信號的可行性，參考心理聲學模型的特性，得出結論:基於人耳聽覺掩蔽效應的隱寫演算法，在隱蔽性上有很大的提高。

Finally, in order to test the imperceptibility and robustness of the two improved algorithms, a lot of experiments were done

本文對兩種水印演算法均進行了大量的不可見性和魯棒性實驗。

The simulation results show that the information hiding technology based on channel coding has better imperceptibility and security

模擬結果表明基於通道編碼的信息隱藏技術具有較好的不可檢測性和較高的安全性。

The simulation results show that it has high hiding capacity, good imperceptibility and certain robustness to jpeg lossy compression

模擬結果表明，該方法提高了信息嵌入量，具有較好的信息隱藏效果，同時對jpeg壓縮具有一定的抵抗能力。

Experiments make it clear that the scheme adopted in this paper fully satisfy the requirements for imperceptibility, robustness and security

相關試驗表明，本文所採用的方案充分保證了水印信息的隱形性、健壯性和安全性，同時，嵌入的水印信息量較大。

Finally, a lot of experiments are performed to test the imperceptibility and robustness of the private watermarking algorithm and blind watermarking algorithm and the two improved algorithms

最後對明文水印演算法和盲水印演算法及其改進的演算法均進行了大量的不可見性和魯棒性實驗。

This paper investigated and compared the main algorithms of audio watermarking and their performance including imperceptibility, roubustness, complexity degree and embedding quantity in detail

摘要對目前音頻水印中的主要演算法進行了系統的描述，並對其在不可見性、魯棒性、計算復雜度以及嵌入量，四個方面作了比較。

The proposed adaptive watermarking scheme enables more energy of watermark to be embedded with imperceptibility, so the stego mesh can be resilient to higher intensity of attacks than with traditional schemes

這使得本演算法能夠在嵌入的水印信息不可見的前提下嵌入更大能量的水印，從而保證水印隱藏對象能夠承受更大強度的攻擊。

From the experiment results, it indicates that, after the watermarked mpeg - 4 video suffer filtering, rotation, scaling and transcoding, the watermark possesses good imperceptibility and robustness

實驗表明，演算法在mpeg - 4水印視頻經過濾波、旋轉、尺度變化、代碼轉換編碼等處理后，水印在可見性和魯棒性等方面取得了良好的效果。

As a special work, there are some meaningful experiments in this thesis. for how to improve the imperceptibility and the robustness, the research achievements on information hiding are classified into the following categories

作為一項特別的工作，本課題對如何提高信息嵌入的隱蔽性和魯棒性做了一些有益的嘗試，對獲得的一系列研究成果進行了總結。

Then we make a deep research on human visual system and wavelet transformation, and a new wavelet watermarking method based on hvs is proposed to solve the conflict between robustness and imperceptibility

在此基礎上，論文又將人眼視覺系統和小波變換結合在一起，提出了一種基於hvs的小波水印演算法，人眼視覺模型的應用緩解了演算法魯棒性和不可見性間的矛盾。

The chaos sequence was applied in these two algorithms to increase its security and was served separately as the random watermark generator and the watermark image encryption techniques. due to the analysis of the image characteristics, we determined the watermark strength by the classification of the image content and obtained better robustness and imperceptibility. new algorithms of meaningful digital watermarking in svd domain with chaotic transform encryption are proposed

混沌序列在這兩類演算法中分別作為隨機水印信號發生器和二值圖像水印的混沌加密手段，具有安全性高、形式簡單的優點；利用hvs特性，分別在時空域和dct頻率變換域中計算圖像內容的自適應嵌入強度，增強了演算法的穩健性；水印的嵌入和檢測計算復雜度小，演算法簡單。

In general, a watermark system must satisfy the two basic requirements : imperceptibility and robustness. in this thesis, we proposed a frequency - based watermarking algorithm using toral automorphisms, in which a kind of toral automorphism is employed to mix a recognizable binary image ( bw ), which contains the copyright information, into a noise - like signal

演算法簡單描述如下：首先用一個環形自同構映射把要嵌入的數字水印映射成偽隨機噪聲，然後把該偽隨機噪聲嵌入到宿主數據頻域的低頻段中，接著把得到的頻域系數進行相應的逆變換得到嵌入水印的圖象，最後對該嵌入水印的圖象進行視覺掩蔽處理。

Experimental results show that the proposed techniques have good imperceptibility and can survive of common image processing operations and jpeg lossy compression with high robustness. the second one considered the watermarking system as a special digital communication system and introduced the ecc as channel coding technique. by using the turbo coding technique, we are able to reduce the watermark bit error rate and improve the robustness of the watermark so as to make counterfeiting attacks more difficult

本文在保證水印不可見性的基礎上和載體圖像的允許降質范圍內，利用rbf神經網路技術實現數字水印信息的最大強度嵌入以增強數字水印抵禦各種惡意攻擊的穩健性;在通信論和信息論模型基礎上，引入ecc （差錯控制編碼）技術降低水印的誤碼率，使得提取水印信息更加可靠，使可能的水印攻擊變得更加困難，從而獲得更好的水印穩健性和可靠性。

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。

Comparing with the image watermarking, the audio watermarking have a few characteristics : 1. comparing with the visual media, audio frequency signal has less sampling points at every time interval. 2. owing to human audition systems, it is more sensitive than human vision systems, therefore, it is more trouble to realize the imperceptibility of audition compared to the vision systems. 3. to stick up to the cut attack, embedded watermark should keep synchronization. 4. because of the bigger memory payload of audio frequency signal, the initial audio frequency signal must be removed during the extract in order to protect the maneuverability of project

數字水印技術是近幾年來學術界興起的一個前沿研究領域，提高演算法的魯棒性、安全性、實用性是數字水印的研究方向。本文提出的基於可視密碼術的小波域下量化系數的魯棒性音頻數字水印方案，其優點在於利用小波變換的多解析度特性在保證水印魯棒性的同時使水印對原始音頻信號的影響達到最小，採用量化系數的方法嵌入水印信息實現了盲水印，提高水印的工程應用價值。