馬賽克視訊中，每一個通過彩色濾波陣列的像素點僅由一個顏色所組成。本篇論文提出一套新的通用式可逆式資料藏匿法。所提方法中，利用空間域以及時間域的關係，取得較好的預測，已得到較佳的色差預測誤差。為確保藏入資料取出時的正確性，我們利用下一張影像，來進行區塊匹配以找到最佳匹配區塊。新提出的區塊搜尋匹配，是為了找出目前影像的最佳匹配區塊。假若區塊匹配誤差小於門檻值，則預測誤差由時間軸來決定；否則，預測誤差由空間域來決定。最後，在所提的方法中，使用差值擴張法來嵌入資料以得到更好的藏量與品質效能。在本實驗中，我們實作八組代表性的測試視訊樣本，實驗結果顯示在相同的容量下，我們所提的通用式可逆式資料藏匿方法和之前的方法相比較，會有3dB的影像品質改良。

Considering a mosaic video in which each pixel in the captured mosaic image with an arbitrary color filter array (CFA) structure is composed of only one color, in this paper, we propose a novel universal reversible data hiding algorithm. In the pro-
posed algorithm, the temporal-spatial correlation is exploited to achieve better pre-
diction with smaller prediction errors in the color difference domain for reversible data hiding. The input mosaic image is divided into a set of blocks, in which each block is classified into non-smooth blocks and smooth blocks. In order to make sure the correctness of extraction, instead of using the backward image frame in the block matching process, the newly proposed block matching process is applied to find the best matched block in the forward image frame. If the matching error is less than the threshold, the temporal domain based data hiding scheme is used; otherwise, the spatial domain based data hiding scheme is adopted. Finally, the difference expansion is conducted by the proposed method to embed hidden data. Based on several 8 typical test videos, experimental results demonstrate that under the same embedding capacity, the proposed universal reversible data hiding algorithm for mosaic videos with arbitrary CFA structures delivers better quality of marked videos than the state-of-the-art algorithms.

參考文獻
[1]I.J. Cox, M. Miller, J. Bloom, Digital Watermarking, Morgan Kaufman, San Francisco, CA, 2001.
[2] J. Tian, Reversible data embedding using a difference expansion, IEEE Trans. Circuits Syst. Video Technol, 13 (2003) 90–896.
[3] W.J. Yang, K.L. Chung, W.N. Yang, and L.C. Lin, Universal chroma subsampling strategy for compressing mosaic video sequences with arbitrary RGB color filter arrays in H.264/AVC, IEEE Trans. Circuits Syst. Video Technol, 23 (2013) 208-226.
[4] W.J.Yang, K.L.Chung, H.Y.M. Liao, Efficient reversible data hiding for color filter array images, Information Sciences, 190 (2012) 208–226.
[5] K.L. Chung, C.H. Shen, L.C. Chang, A novel SVD- and VQ-based image hiding scheme, Pattern Recognition Lett. 22 (2001) 1051–1058.
[6] K.L. Chung, W.N. Yang, Y.H. Huang, S.T. Wu, Y.C. Hsu, On SVD-based watermarking algorithm, Appl. Math. Comput. 188 (2007) 54–57.
[7] I.J. Cox, M. Miller, J. Bloom, Digital Watermarking, Morgan Kaufman, San Francisco, CA, 2001.
[8] C.T. Hsu, J.L. Wu, Hidden digital watermarks in images, IEEE Trans. Image Process. 8 (1999) 58–68.
[9] C.S. Lu, H.Y. Mark Liao, Multipurpose watermarking for image authentication and protection, IEEE Trans. Image Process. 10 (2001) 1579–1592.
[10] J.M. Barton, Method and Apparatus for Embedding Authentication Information Within Digital Data, US Patent# 5 646 997, 1997.
[11] Y.Q. Ni, N.A. Shi, W. Su, Reversible data hiding, IEEE Trans. Circuits Syst. Video Technol. 16 (2006) 354–362.
[12] B. E. Bayer, “Color imaging array,” U.S. Patent 3 971 065, Jul. 1976.
[13] [Online]. Available: http://trace.eas.asu.edu/yuv/
[14] T. Sugiyama, “Image-capturing apparatus,” U.S. Patent App. 0 231 618, Oct. 2005.
[15] W.J. Yang, K.L. Chung, L.C. Lin, and C.H. Lin, “Universal Reversible Data Hiding for Arbitrary RGB-CFA Captured Images,” IEEE, Information, Communications and Signal Processing (ICICS) 2013 9th International Conference, (2013) 1-5.
[16]K.L Chung, W.J. Yang, T.C. Chang and H.Y Mark Liao, “Efficient Multilevel Reversible Data Hiding for Video Sequences Using Temporal and Spatial Approach”
Asia-Pacific Signal and Information Processing Association, 2009 Annual Summit and Conference, International Organizing Committee. (2009) 573-582.