基于MPEG的数字水印技术研究
摘要
数字水印是近年来出现的数字产品版权保护技术，它可以标识作者等版权保护信息和认证信息。作为密码学的加密或置乱技术的补充，使用水印技术可以鉴别出非法复制和盗用的数字产品，保护数字产品的合法拷贝和传播，因此它一出现即成为热点问题。但是目前数字水印技术还是处于其发展初期阶段，尚缺乏有关数字水印的理论，可以说从理论到实际都有许多问题有待解决。
本文主要针对数字水印技术在MPEG视频版权保护中的应用，研究了现有的静态水印技术和MPEG视频水印技术的异同点，分析了将现有的静态水印技术加之于MPEG视频上的可能性以及可能出现的问题，并提出了一种实用的用于MPEG视频水印的算法，给出了分析和实际验证的结果。
在第一章中简要介绍了课题背景和当前的研究状况，在第二章中介绍了数字水印技术的基本原理和目前在静态图像上添加水印的常用算法。在第三章中介绍了与MPEG系统解码相关的一些概念，在第四章中分析了MPEG编解码算法。在第五章中，首先根据MPEG文件格式及其编解码算法的特点提出了在视频中嵌入水印的位置，比较了它和静态水印技术的异同点。给出了一种衡量MPEG视频水印技术的方法。然后我们研究了空域水印算法，将该算法应用于MPEG视频，给出了模拟实验结果，并对实验的结果进行了分析。在第五章中我们还主要研究了在DCT变换域添加水印的算法，以C++编程，实现了将这种算法应用于MPEG视频，给出了实验结果并分析了造成这种结果的原因。
在对以上算法进行分析的基础上，我们吸收了DCT变换类型算法中分块嵌入水印的思想，但是在对DCT变换后的系数进行调整时，采用了逐步调整的算法，避免了DCT变换类型算法中的整数舍入误差。同时考虑到P帧和B帧中运动向量计算的特点，将嵌入水印的块的位置进行了一定程度的偏移，这样就有利于P帧和B帧中水印信号的检测。经过实验证明了这种方法对于I帧的压缩仍然具有100％的检测能力，即使对于P帧和B帧的压缩也有不错的效果。
Digital watermark technology has been introduced to protect the copyright of digital products in recent years. With this technology, you can embed the copyright information and authentication information such as the author or others. And as the complementarity of cipher technology, it can identify the digital product which has been illegally copied, and it can protect the legal copied product. Because of these merits, the watermark technology has been hot since its appearance.
Now there are many papers on digital watermark technology, but most of them are focused on how to design a sheme or how to attack a watermark. And most of these themes or products are not so perfect because relexation of the basic theory about digital watermark technology. We can say that we are still in the early time of this technology and there are many difficulties.
In this paper, the usage of watermark technology, especially in the MPEG system, is discussed. The technology of static watermark and the MPEG watermark techonology are compared. We consider the possibility to apply the static wartermark technology on MPEG system directly, and we also consider the problems may occur. At last, a new method of embeding and detecting watermark are introduced with the result of experiments.
In chapter1, the backgroud and the state of watermark technology are introduced. In chapter2, we discuss the basic theory and the method of watermarking used frequently. In chapter 3 and chapter 4, the MPEG encoding algorithm and its file format are introduced. In chapter 5, we discuss where to embed the watermark based on the MPEG's encoding algorithm, the differences between MPEG system and static image are considered, we also discuss how to mesure the qulity of a kind of watermarking method.
In chapter 5, a spatial method of watermarking is applied on the MPEG system directly, we analyse the result and discuss the fault of this method. We also test another method based on DCT transform, find its fault and consider how to avoid.
At last, a new method based on DCT transform is considered, we test it and get a better result than the two methods we have discussed.
本文主要针对数字水印技术在MPEG视频版权保护中的应用，研究了现有的静态水印技术和MPEG视频水印技术的异同点，分析了将现有的静态水印技术加之于MPEG视频上的可能性以及可能出现的问题，并提出了一种实用的用于MPEG视频水印的算法，给出了分析和实际验证的结果。
在第一章中简要介绍了课题背景和当前的研究状况，在第二章中介绍了数字水印技术的基本原理和目前在静态图像上添加水印的常用算法。在第三章中介绍了与MPEG系统解码相关的一些概念，在第四章中分析了MPEG编解码算法。在第五章中，首先根据MPEG文件格式及其编解码算法的特点提出了在视频中嵌入水印的位置，比较了它和静态水印技术的异同点。给出了一种衡量MPEG视频水印技术的方法。然后我们研究了空域水印算法，将该算法应用于MPEG视频，给出了模拟实验结果，并对实验的结果进行了分析。在第五章中我们还主要研究了在DCT变换域添加水印的算法，以C++编程，实现了将这种算法应用于MPEG视频，给出了实验结果并分析了造成这种结果的原因。
在对以上算法进行分析的基础上，我们吸收了DCT变换类型算法中分块嵌入水印的思想，但是在对DCT变换后的系数进行调整时，采用了逐步调整的算法，避免了DCT变换类型算法中的整数舍入误差。同时考虑到P帧和B帧中运动向量计算的特点，将嵌入水印的块的位置进行了一定程度的偏移，这样就有利于P帧和B帧中水印信号的检测。经过实验证明了这种方法对于I帧的压缩仍然具有100％的检测能力，即使对于P帧和B帧的压缩也有不错的效果。
Digital watermark technology has been introduced to protect the copyright of digital products in recent years. With this technology, you can embed the copyright information and authentication information such as the author or others. And as the complementarity of cipher technology, it can identify the digital product which has been illegally copied, and it can protect the legal copied product. Because of these merits, the watermark technology has been hot since its appearance.
Now there are many papers on digital watermark technology, but most of them are focused on how to design a sheme or how to attack a watermark. And most of these themes or products are not so perfect because relexation of the basic theory about digital watermark technology. We can say that we are still in the early time of this technology and there are many difficulties.
In this paper, the usage of watermark technology, especially in the MPEG system, is discussed. The technology of static watermark and the MPEG watermark techonology are compared. We consider the possibility to apply the static wartermark technology on MPEG system directly, and we also consider the problems may occur. At last, a new method of embeding and detecting watermark are introduced with the result of experiments.
In chapter1, the backgroud and the state of watermark technology are introduced. In chapter2, we discuss the basic theory and the method of watermarking used frequently. In chapter 3 and chapter 4, the MPEG encoding algorithm and its file format are introduced. In chapter 5, we discuss where to embed the watermark based on the MPEG's encoding algorithm, the differences between MPEG system and static image are considered, we also discuss how to mesure the qulity of a kind of watermarking method.
In chapter 5, a spatial method of watermarking is applied on the MPEG system directly, we analyse the result and discuss the fault of this method. We also test another method based on DCT transform, find its fault and consider how to avoid.
At last, a new method based on DCT transform is considered, we test it and get a better result than the two methods we have discussed.
引文
[1]李燕 刘建华．数字媒体版权保护和信息保密的新途径一数字水印技术．桂林航天工业高等专科学校学报．2002，7
[2]夏鸿斌 须文波等．数字水印技术．江南大学学报：自然科学版．2002，1
[3]姜楠 赵庆祯．数字水印在信息隐藏中的应用．计算机应用与软件．2002，19
[4]刘中伟 黄凯奇等．MPEG-4中的知识产权管理和保护技术．电声技术．2002,(3)
[5]杨义先 钮心忻．多媒体信息伪装综论．通信学报．2002，23
[6]张彤 王育民．信息隐藏技术及其在信息安全中的应用．中兴通讯技术．2002，8
[7]郭捷 施鹏飞．数字水印技术及其应用．图像识别与自动化．2001，(2)
[8]孙锐 孙洪．数字图像信息隐藏技术．通信技术．2001，(007)
[9]祁明 刘迎风．信息隐藏与数字水印技术及其应用．通信技术．2001，(006)
[10]易开祥 孙鑫等．数字水印技术研究进展．中国图像图形学报．2001，6
[11]陈明奇 钮心忻等．数字水印的研究进展和应用．通信学报．2001,22
[12]易开祥 孙鑫等．一种新的基于图像内容的半易损水印技术．系统仿真学报．2002，14
[13]王道顺 Dilian Yang等．一种抗裁剪和旋转的盲水印嵌入新方法．系统仿真学报．2002，14
[14]张力 韦岗．闭环图像数字水印技术．中国图像图形学报．2002，7
[15]张力 韦岗．一种基于图像内容的小波域鲁棒水印技术．中国图像图形学报．2002，7
[16]胡永健 余英林．DWT域最佳水印检测器的设计及其应用．华南理工大学学报：自然科学版．2002，30
[17]赵春晖．基于优化检测原理和鲁棒非加性水印算法．哈尔滨工程大学学报．2002,23(4)．
[18]王慧琴 李人厚等．一种结合空间域和DCT域的数字水印新算法．通信学报．2002,23(8)
[19]钟桦 焦李成等．一种新标识符水印算法．电子与信息学报．2002,24(8)
[20]潘蓉 高有行．基于小波变换的图像水印嵌入方法．中国图像图形学报．2002，7(7)
[21]陈名华 何芸．一种基于数字水印的错误检测和定位技术．清华大学学报：自然科学版．2002，42(7)
[22] R. B. Wolfgang, E. J. Delp. A watermark for digital images. International Conference on Images Processing, Lausanne, Switzerland, 16-19 Sept. 2000
[23] G. C. Langelaar, Watermarking by D.C.T. Coefficient Removal: A Statistical Approach to Optimal Parameter Settings. International Conference on Images Processing, Lausanne, Switzerland, 16-19 Sept. 2000
[24] R. J. Anderson. On The Limits of Steganography. International Conference on Images Processing, Lausanne, Switzerland, 16-19 Sept. 2000
[25] R. G. van Schyndel. A DigitalWatermark. International Conference on Image Processing, Austin, Texas, U.S.A., 2001
[26] G. Caronni. Assuring Ownership Rights for Digital Images. International Conference on Image Processing, Austin, Texas, U.S.A., 2001
[27] G. C. Langelaar. Copy Protection for Multimedia Data based on Labeling Techniques.International Conference on Image Processing, Austin, Texas, U.S.A., 2001
[28] I. J. Cox, A Secure, RobustWatermark for Multimedia. International Conference on Image Processing, Austin, Texas, U.S.A., 2001
[29] M. D. Swanson. Transparent Robust Image Watermarking. International Conference on Image Processing. IEEE, 1996
[30] W. J. Dowling. Watermarking digital images for copyright protection. Signal and Image Processing, vol. 143 no. 4 pp. 250-256, Aug. 1999
[31] T. Pun. Rotation, scale and translation invariant spread spectrum digital image watermarking. Signal Processing, vol. 66 no. 3 pp. 303 - 317, May 1998
[32] J. F. Delaigle. Watermarking algorithm based on a human visual model. Signal Processing, vol. 76 no. 4 pp. 152 - 154, Aug 1998
[33] F. Hartung. Fast Public-KeyWatermarking of Compressed Video. International Conference on Image Processing (ICIP'97), Santa Barbara, California, U.S.A., Oct. 1997
[34] A. Bors. Image watermarking using block site selection and D.C.T. domain constraints. Optics Express, vol. 3 no. 12 pp. 512-523, 7 Dec. 1998
[35] H.-J. M. Wang. Wavelet-based digital image watermarking. Optics Express, vol. 3 no. 12 pp. 491-496, 7 Dec. 1998
[36] X.-G. Xia. Wavelet transform based watermark for digital images. Optics Express, vol. 3 no. 12 pp. 497-511, 7 Dec. 1998
[37] P. Davern. Fractal Based Image Steganography. Optics Express, vol. 3 no. 12 pp. 525-528, 7 Dec. 1998
[38] I. J. Cox. Public watermarks and resistance to tampering. International Conference on Image Processing (ICIP'97), Santa Barbara, California, U.S.A., 26-29 Oct. 1997
[39] I. J. Cox. Some General Methods for Tampering with Watermarks. IEEE Journal of Selected Areas in Communications, vol. 16 no. 4 pp. 587-593, May 1998
[40] D. Kundur. Improved robust watermarking through attack characterisation. Optics Express, vol. 3 no. 12 pp. 485-490, 7 Dec. 1998
[2]夏鸿斌 须文波等．数字水印技术．江南大学学报：自然科学版．2002，1
[3]姜楠 赵庆祯．数字水印在信息隐藏中的应用．计算机应用与软件．2002，19
[4]刘中伟 黄凯奇等．MPEG-4中的知识产权管理和保护技术．电声技术．2002,(3)
[5]杨义先 钮心忻．多媒体信息伪装综论．通信学报．2002，23
[6]张彤 王育民．信息隐藏技术及其在信息安全中的应用．中兴通讯技术．2002，8
[7]郭捷 施鹏飞．数字水印技术及其应用．图像识别与自动化．2001，(2)
[8]孙锐 孙洪．数字图像信息隐藏技术．通信技术．2001，(007)
[9]祁明 刘迎风．信息隐藏与数字水印技术及其应用．通信技术．2001，(006)
[10]易开祥 孙鑫等．数字水印技术研究进展．中国图像图形学报．2001，6
[11]陈明奇 钮心忻等．数字水印的研究进展和应用．通信学报．2001,22
[12]易开祥 孙鑫等．一种新的基于图像内容的半易损水印技术．系统仿真学报．2002，14
[13]王道顺 Dilian Yang等．一种抗裁剪和旋转的盲水印嵌入新方法．系统仿真学报．2002，14
[14]张力 韦岗．闭环图像数字水印技术．中国图像图形学报．2002，7
[15]张力 韦岗．一种基于图像内容的小波域鲁棒水印技术．中国图像图形学报．2002，7
[16]胡永健 余英林．DWT域最佳水印检测器的设计及其应用．华南理工大学学报：自然科学版．2002，30
[17]赵春晖．基于优化检测原理和鲁棒非加性水印算法．哈尔滨工程大学学报．2002,23(4)．
[18]王慧琴 李人厚等．一种结合空间域和DCT域的数字水印新算法．通信学报．2002,23(8)
[19]钟桦 焦李成等．一种新标识符水印算法．电子与信息学报．2002,24(8)
[20]潘蓉 高有行．基于小波变换的图像水印嵌入方法．中国图像图形学报．2002，7(7)
[21]陈名华 何芸．一种基于数字水印的错误检测和定位技术．清华大学学报：自然科学版．2002，42(7)
[22] R. B. Wolfgang, E. J. Delp. A watermark for digital images. International Conference on Images Processing, Lausanne, Switzerland, 16-19 Sept. 2000
[23] G. C. Langelaar, Watermarking by D.C.T. Coefficient Removal: A Statistical Approach to Optimal Parameter Settings. International Conference on Images Processing, Lausanne, Switzerland, 16-19 Sept. 2000
[24] R. J. Anderson. On The Limits of Steganography. International Conference on Images Processing, Lausanne, Switzerland, 16-19 Sept. 2000
[25] R. G. van Schyndel. A DigitalWatermark. International Conference on Image Processing, Austin, Texas, U.S.A., 2001
[26] G. Caronni. Assuring Ownership Rights for Digital Images. International Conference on Image Processing, Austin, Texas, U.S.A., 2001
[27] G. C. Langelaar. Copy Protection for Multimedia Data based on Labeling Techniques.International Conference on Image Processing, Austin, Texas, U.S.A., 2001
[28] I. J. Cox, A Secure, RobustWatermark for Multimedia. International Conference on Image Processing, Austin, Texas, U.S.A., 2001
[29] M. D. Swanson. Transparent Robust Image Watermarking. International Conference on Image Processing. IEEE, 1996
[30] W. J. Dowling. Watermarking digital images for copyright protection. Signal and Image Processing, vol. 143 no. 4 pp. 250-256, Aug. 1999
[31] T. Pun. Rotation, scale and translation invariant spread spectrum digital image watermarking. Signal Processing, vol. 66 no. 3 pp. 303 - 317, May 1998
[32] J. F. Delaigle. Watermarking algorithm based on a human visual model. Signal Processing, vol. 76 no. 4 pp. 152 - 154, Aug 1998
[33] F. Hartung. Fast Public-KeyWatermarking of Compressed Video. International Conference on Image Processing (ICIP'97), Santa Barbara, California, U.S.A., Oct. 1997
[34] A. Bors. Image watermarking using block site selection and D.C.T. domain constraints. Optics Express, vol. 3 no. 12 pp. 512-523, 7 Dec. 1998
[35] H.-J. M. Wang. Wavelet-based digital image watermarking. Optics Express, vol. 3 no. 12 pp. 491-496, 7 Dec. 1998
[36] X.-G. Xia. Wavelet transform based watermark for digital images. Optics Express, vol. 3 no. 12 pp. 497-511, 7 Dec. 1998
[37] P. Davern. Fractal Based Image Steganography. Optics Express, vol. 3 no. 12 pp. 525-528, 7 Dec. 1998
[38] I. J. Cox. Public watermarks and resistance to tampering. International Conference on Image Processing (ICIP'97), Santa Barbara, California, U.S.A., 26-29 Oct. 1997
[39] I. J. Cox. Some General Methods for Tampering with Watermarks. IEEE Journal of Selected Areas in Communications, vol. 16 no. 4 pp. 587-593, May 1998
[40] D. Kundur. Improved robust watermarking through attack characterisation. Optics Express, vol. 3 no. 12 pp. 485-490, 7 Dec. 1998