摘要
以影像內容調整權重之忘卻性數位浮水印模組
葉富豪
電腦網路和資訊數位化帶來了易散佈和易修改的便利性，使得多媒體資料之取得十分容易。如何確認多媒體資料使用之合法性，以確保創作者之著作權，便顯得十分重要。近來所發展之數位浮水印技術，正可有效解決多媒體資料著作權歸屬問題。
本研究主要之目的，是發展忘卻性(Oblivious)數位影像浮水印技術，即在不需原始影像之輔助下，便可確認浮水印的存在與否，進而協助鑑定著作權之歸屬。而採用之方法，主要是將影像分為數個長寬相等的子區塊，並利用子區塊的材質與亮度之分析，判斷子區塊插入浮水印後，是否容易造成子區塊內影像失真，並給予每個子區塊適當權重，以插入不同能量之浮水印資料。最後並以影像修正函數，校正插入浮水印後之影像邊緣失真，以維護影像之視覺品質。
實驗結果顯示，研究所提之方法能有效防禦諸多影像處理技術對於浮水印的破壞，包括：影像切割(切除95%)、有損失壓縮(壓縮比為12)、影像增強及同時插入多個浮水印等破壞方式。

ABSTRACT
A Content Based Oblivious Watermarking Model
By
Fu-Hao Ya
Computer network and digitized information, which bring the convenience of spreading and modifying, make it much easier to acquire multimedia data. Therefore, it becomes more and more important to affirm the legal use of multimedia data to protect the intellectual property of the creators. And Digital Watermarking, developed recently, has been proposed as an efficient way to protect copyright.
The principal purpose of this research lies in the development of Oblivious watermarking, which can ensure the existence of watermarking independently without the assistance of original images, and thus can authenticate the authority of copyright. The main method we adopted is to divide the whole image into several equivalent sub-blocks, and to determine if the embedment of the watermark would cause the distortion of the image by analyzing the texture and brightness of each sub-block. Then, each sub-block is given its proper weight, by which we embed the watermark of different energy in it, and, lastly, we amend the edge of the whole image after the embedment of the watermark with a function to retrieve the distortion.
The result of this experiment reveals that the method we took, as mentioned above, is able to effectively defend the attacks which other image processing techniques would cause, such as image cropping (95% cropped), lossy compression (rate of compression=12), image enhancement, multiple watermarks, etc.

參考資料
[1] A. Piva, M. Barni, and F. Bartolini, “Copyright Protection of digital image by Means of frequency Domain Watermarking”, http://www-nt.e-technik.uni-erlangen.de/%7Ehartung/watermarkinglinks.html, 1998.
[2]A. Piva, M. Barni, F. Bartolini, and V. Cappellini, “DCT-based watermark recovering without resorting to the uncorrupted original image”, Proceedings of 4th IEEE International Conference on Image Processing ICIP'97, Santa Barbara, CA, USA, Vol 1, pp. 520-523, October 26-29, 1997.
[3]A. Piva, M. Barni, F. Bartolini, and V. Cappellini, “A watermarking technique for the protection of digital images IPR”, European Multimedia, Microprocessor Systems and Electronic Commerce EMMSEC 97, Florence, Italy, November 3-5, 1997.
[4]A. S. Lewis and G. Knowles, “Image compression using the 2-D wavelet transform”, IEEE Transactions on Image Processing, 1992.
[5 ]C. C. Tseng, R. D. Lin and S. L. Lee, “Image watermarking based on toral automorphism, block DC value Quantization and error correcting codec”, Conference on Computer Vision, Graphic and Image Processing, pp. 158-165 , April, 1999.
[6]C. Ting. Hsu and J. L. Wu, “Hidden digital watermarks in Images”, IEEE Transactions On Image Processing, Vol. 8. No. 1. JANUARY, 1999.
[7]C. I. Podilchuk, and W. Zeng, “Image-Adaptive watermarking using visual models”, IEEE Journal On Selected Areas in Communications, Vol . 16. No. 4, May, 1998.
[8]C. S. Lu, Hong Y. Liao, S. K.Huang, and C. J. Sze, “Cocktail watermarking on image and audios”, Conference on Computer Vision, Graphic and Image Processing, pp. 30-37, April, 1999.
[9]S. Craver, N. Memon, B. L. Yeo, and M. Yeung, “Resolving rightful ownerships with invisible watermarking techniques: limitations, attacks, and implications”, IEEE Journal on Selected Areas in Communications, Vol. 16. No. 4,May ,1998.
[10]D. Boneh and J. Shaw,“Collusion-secure fingerprinting for digital data”, IEEE Transactions on Information Theory 44, pp.1897-1905, September, 1998.
[11]D. Kundur and D. Hatzinakos, “Improve robust watermarking through attack characterization”, http://www-nt.e-technik.uni-erlangen.de/%7Ehartung/watermarkinglinks.html, 1998.
[12]D. Kundur and D. Hatzinakos, “A Robust Digital Image Watermarking Scheme using Wavelet-Based Fusion”, Proceedings of IEEE International Conference on Image Processing, Santa Barbara, California, Vol. 1, pp. 544-547, October 1997.
[13]F. Bartolini, M. Barni, V. Cappellini, and A. Piva, “Mask building for perceptually hiding frequency embedded watermarks”, Proceedings of 5th IEEE International Conference on Image Processing ICIP'98, Chicago, Illinois, USA, Vol 1, pp. 450-454, October 4-7, 1998.
[14]F. Jurie, “A new log-polar mapping for space variant imaging.Application to face detection and tracking”, Patten Recognition , pp. 865-875, 1999.
[15]H. Frank, K. S. Jonathan, and G. Bernd, “Spread Spectrum Watermarking:Malicious Attacks and Counterattacks”, Telecommunications Labatory, University of Erlangen-Nuremberg, 1999.
[16]G. C. M. Silvestre and W. J. Dowling, “Image Watermarking Using Communication Techniques”, Image Processing and Its Applications, No. 443. pp. 15-17, 1997.
[17]I. J. Cox, J. Kilian, T. Leighton, and T. Shammoon, “Secure spread spectrum watermarking for multimedia”, Transactions on Image Processing, Vol. 6. No. 12, December, 1997.
[18]J. Fridrich , “Applications of Data Hidding In Digital Image”, ISPACS, 1998.
[19]J.J.K.O. Ruanaidh, W. J. Dowling, and F. M. Boland, “Phase watermarking of digital images”, Proceedings International Conference on Image Processing, 1996.
[20]J. J. K. O. Ruanaidh and T. Pun, “Rotation,scale and translation invariant spread spectrum digital image watermarking”, Signal Processing, pp. 303-317, 1998.
[21]J. Johnston, N. Jayant and R. Safranek, “ Signal compression based on models of human perception”, Proceedings of the IEEE, Vol. 81, No. 10, October, 1993.
[22]H. K. Ju, W. D. Lee, and H. P. Jin, “A watermarking with two signatures”, Multimedia Signal Processing, 1998.
[23] L.Torres and M.Kunt, “Video Coding”, The Second Generation Approach. Kluwer Academic Publishers, 1995.
[24]M. Barni, F. Bartolini, V. Cappellini, and A. Piva, “Copyright protection of digital images by embedded unperceivable marks”, http://www-nt.e-technik.uni-erlangen.de/%7Ehartung/watermarkinglinks.html, 1997.
[25]M. Barni, F. Bartolini, V. Cappellini, and A. Piva, “A DCT domain system for robust image watermarking”, Signal Processing, pp.357-372, 1997
[26]M. Barni, F. Bartolini, V. Cappellini, and A. Piva, “Robust watermarking of still images for copyright protection”, Proceedings 13th International Conference on Digital Signal Processing DSP97, Santorini, Greece, Vol. 2, pp. 499-502, July 2-4, 1997.
[27]M. Barni, F. Bartolini, V. Cappellini, A. Lippi, and A. Piva, “A DWT-based algorithm for spatio-frequency masking of digital signatures”, Proceedings of SPIE Vol. 3657, Security and Watermarking of Multimedia Contents, Electronic Imaging '99, San Jose, CA, January, 1999.
[28]M. J. J. J. B. Maes and C. W. A. M. Overveld, “Digital Watermarking by Geometric Warping”, IEEE Image Processing, 1998.
[29 ]M. D. Swanson, B. Zhu, and A. H.Tewfik, “Robust Data Hiding for Image”, IEEE Digital Signal Processing Workshop(DSP 96), Loen, Norway, pp.37-40,September, 1996.
[30]M. D. Swanson, K. MEI, and A. H. Tewfik, “Multimedia Data-embedding and Watermarking Technologies”, Proceeding of the IEEE, Vol. 86. NO. 6. June, 1998.
[31] S. K. Mohan and K. R. R. Rajmohan, “Content Based Watermarking of Images”, ACM Multimedia 98-Electronic Proceedings, 1998.
[32]S. C. Pei, Y. H. Chen, and R. F. Torng, “Digital Image and Video Watermarking Utilizing Just-Noticeable-Distortion Model”, Conference on Computer Vision, Graphic and Image Processing, pp. 174-182, 1999.
[33]S. D. Servetto, C. I. Podilchuk, and K. Ramchandran, “Capacity Issues In Digital Image Watermarking”, International Conference on Image Processing, 1998.
[34 ] R. G. V. Schyndel, A. Z. Tirkel, and C. F. Osborne, “A Digital Watermark”, IEEE International Conference on Image Processing, 1994.
[35]G. Voyatzis and I.Pitas ,“ Protecting digital image copyrights: a framework”, IEEE Computer Graphics and Applications, 1999.