本論文提出一種基於YCbCr色彩空間之彩色數位浮水印影像演算法，目的在有效防止浮水印遭受各種攻擊的破壞，並保持浮水印的透明度。為了加強浮水印的強韌度，本研究整合了離散小波轉換、離散餘弦轉換以及雜訊可見函式等技術；同時為了增加浮水印的透明度，將浮水印嵌入中高頻位置，使得浮水印在客觀的數據或主觀的判定上皆有良好的效果。本演算法所加密的浮水印經過壓縮、模糊、銳化、亮度等攻擊，皆仍具有良好的透明度與強韌度，使彩色數位影像的智慧財產權得到更多的保護。

In this paper, we proposed an algorithm to improve the robustness and transparency for color image watermarking with YCbCr color space. In order to improve the robustness, we integrate Discrete Wavelet Transform (DWT), Discrete Cosine Transform (DCT) and Noise Visibility Function (NVF). Besides, the transparency of watermark was improved by embedding the watermark in the mid-high frequency range. Several watermarked color images with the proposed algorithm were tested against the attacks of compression, blur, sharpen and brightness. The experimental results show that the proposed algorithm of encryption for color image watermark is available for protecting the intellectual property of color image.

[1] 經濟部智慧財產局(2012)。查禁仿冒統計。2012年，5月1日，取自http://www.tipo.gov.tw/ch/index.aspx
[2] IEEE Xplore Digital Library(2012). [Online]. Availible at http://ieeexplore.ieee.org/Xplore/guesthome.jsp
[3] M. D. Swanson, M. Kobayashi, and A. H. Tewfik, “Multimedia data-embedding and watermarking technologies,” Proceedings of the IEEE, 1998, Vol. 86, No. 6, pp. 1064–1087.
[4] Chang-Hsing Lee; Yeuan-Kuen Lee；“An adaptive digital image watermarking technique for copyright protection” Consumer Electronics, IEEE Transactions on, Volume: 45 , Issue: 4 , Nov 1999 , Page(s):1005 – 1015.
[5] F. A. P. Petitcolas, R. J. Anderson, and M. G. Kuhn (1999), “Information hiding-a survey,” Proceedings of the IEEE, vol. 87, no. 7, pp. 1062–1078, 1999.
[6] Hu Y., Kwong S., “An image fusion based visible watermarking algorithm”, Proc. of the 2003 Int. Symp. on Circuits and Systems, vol. 3, pp. 794 -797, May 25-28, 2003.
[7] Zhang, X., Wang, S.: Fragile Watermarking with Error-Free Restoration Capability. IEEE Transactions on Multimedia 10(8), 1490-1499 (2008).
[8] J. Fridrich, M. Goljan, Images With Self-correcting Capabilities, Proceedings of IEEE International Conference on Image Processing, 1999: 792–796.
[9] C. Ramos, R. R. Reyes, M. N. Miyatake, and H. P. Meana, “Image Authentication Scheme Based on Self-embedding Watermarking”, Lecture Notes In Computer Science, Vol. 5856, pp. 1005-1012, 2009.
[10] N. Wang, Y. Wang and X. Li , “A Novel Robust Watermarking Algorithm based on DWT and DCT,” International Conference on Computational Intelligence and Security, vol. 1, pp. 437–441, 2009.
[11] R. G. van Schyndel, A. 2. Tirkel, N. R. A. Mee, C. F. Osborne, "A digital watermark," Proceedings of the International Conference on Image Processing, November, 1994, Austin, Texas, vol. 2, pp. 86-90.
[12] Maity, S. P. Kundu, M. K. “Robust and Blind Spatial Watermarking In Digital Image”, Proc. 3rd Indian Conf. on Computer Vision, Graphics and Image Processing (ICVGIP '2002), pp. 388 -393, Ahmedabad, India, 16-18th December, 2002.
[13] G. Voyatzis and I. Pitas, "Chaotic watermarks for embedding in the spatial digital image domain", Proc. ICIP98, vol. II, pp.432 - 436 , 1998.
[14] Chan, C. and L. Cheng, 2004. Hiding Data in Images by Simple LSB Substitution, Pattern Recognition, 37(3):469-474.
[15] M. Vetterli and J. Kovačević, 1995. Wavelets and Subband Coding. Prentice Hall, USA.
[16] W. H. Lin, Y. R. Wang, S. J. Horng, T. W. Kao and Y. Pan, “A blind watermarking method using maximum wavelet coefficient quantization,” Expert Systems with Applications, vol. 36, issue. 9, Nov. 2009.
[17] Y. S. Kim, O.H.Kwon, R.H. Park, “Wavelet based watermarketing method for digital images using the human visual system”Circuits and System,ISCAS'99.Proceeding of the 1999 IEEE International Symposium on Volume:4,Page(s):80-83 vol.4, 1999.
[18] R. M. Zhao, H. Lian, H. W. Pang and B. N. Hu, “A Blind Watermarking Algorithm Based on DCT,” Intelligent Information Technology Application, vol. 3, pp. 821–824, 2008.
[19] Ali Al-Haj, “Combined DWT-DCT Digital Image Watermarking,” Journal of Computer Science 3 (9): 740-746, 2007.
[20] G. Gao, “A Blind Grayscale Watermark Algorithm Based on Chaos and Mixed Transform Domain,” Computer and Automation Engineering (ICCAE), vol. 1, pp. 658–662, 2010.
[21] Fanzhi Kong, Yizhun Peng, “Color Image Watermarking Algorithm Based On HSI Color Space ”, Industrial and Information Systems (IIS),vol.2, pp. 464 -467, July 10-11, 2010.
[22] Xie Bin, “ A Blind Watermarking Algorithm Based on Color Space Conversion in DCT Domain ”, Control, Automation and Systems Engineering (CASE), pp. 1 -3, July 30-31, 2011.
[23] 陳舒菁 ,“ ROI Recoverable Digital Watermarking for Medical Images ”,Chung Yuan Christian University,June, 2007.
[24] 戴顯權，陳政一，JPEG 2000，紳藍出版社， 2002。
[25] G. Voyatzis and I. Pitas, “Applications of Toral Automorphisms in Image Watermarking”, In Proceeding of the IEEE International Conference on Image Processing, Vol III, pp. 219-222, 1996.
[26] S. Voloshynovskiy , A. Herrigel , N. Baumgaertner and T. Pun, “A Stochastic Approach to Content Adaptive Digital Image Watermarking,” Proceedings of the Third International Workshop on Information Hiding, pp.211-236, Sep. 1999.
[27] 陳瑞熙, 高堅志, 陳俊佑, 張文豪, “彩色影像數位浮水印演算法之強健性探討,” 聖約翰學報 第二十四期, pp. 27-33, 2007.
[28] University of Southern California (2012). Available at http://sipi.usc.edu/database/database.php