臺灣博碩士論文加值系統

數位視訊傳輸隨著科技的快速發展朝向無線通訊應用，而經壓縮過後的視訊資料容易因通道干擾產生錯誤，造成視訊品質降低。錯誤遮隱是一種在不增加傳輸資料量或通道頻寬的前提下，於接收端改善視訊畫面品質的重要技術。錯誤遮隱依照回復原理可以分成時間域與空間域兩大類，各有其優缺點與使用時機，因此如何整合兩域的方法，利用各自的優點來增加回復影像的品質成為近期錯誤遮隱研究的重點。
本論文提出一個整合時間域與空間域的錯誤遮隱法。首先以時間域原理中移動向量資料為起始，根據移動向量匹配與否的原則，把欲回復的區塊分割成數個區域並選擇不同方式的錯誤遮隱演算法回復。其中移動向量匹配的部分根據邊緣匹配原理做回復；當區塊內有某區域不適合用邊緣匹配回復時，則使用空間域的改良式最接近像素內插法回復。
由模擬結果可知在不增加太多運算複雜度的前提下，本論文所提之方法在尖峰訊雜比值(PSNR)方面比邊緣匹配法(Boundary Matching Algorithm, BMA)以及經修改的邊界匹配法(Modified Boundary Matching Algorithm, MBMA)平均增加0.05至1.91dB之間。總括來說，整合時間域與空間域錯誤遮隱法對於區塊內有不同物件或是物件與背景交界時能發揮最大的效果。

Digital video transmission turns to wireless communication application with rapid technology development. The compressed video data are easily corrupted by channel interference. Error concealment is a technique used at the decoder side for improving decoded video quality without any increase of transmission data or channel bandwidth. Error concealment techniques can be classified into temporal and spatial domains by their error recovery principles, and each of them has its own trait and application condition. Thus, how to integrate the methods of both domains and make use of their advantages to improve image quality become a major research topic in recent error concealment study.
In this thesis, an error concealment scheme combining temporal and spatial domains algorithms is proposed. According to the matching degree of motion vectors, a macroblock in error is divided into several areas. Any areas suitable for the temporal-domain boundary matching method are recovered first. The remaining areas are recovered by improved spatial-domain nearest pixels interpolation method.
The simulation results show that the proposed method is 0.05-1.91 dB better than BMA (Boundary Matching Algorithm) and MBMA (Modified Boundary Matching Algorithm) on the average in terms of peak signal to noise ratio (PSNR) without increasing too much computational complexity. Overall, the temporal and spatial domain combining error concealment algorithms work well in the macroblocks with different objects or some boundary between objects and background.

中文摘要i
英文摘要ii
誌謝iii
目錄iv
圖目錄vi
第一章 緒論1
1.1 研究背景1
1.1.1 資料保護概論2
1.1.2 錯誤遮隱2
1.2 研究動機與目的3
1.3 研究方法與步驟3
1.4 論文架構3
第二章 視訊壓縮標準5
2.1 視訊壓縮原理簡介5
2.1.1 時間冗餘性6
2.1.2空間冗餘性7
2.1.3 編碼冗餘性7
2.2 H.26X系列視訊壓縮標準8
2.2.1 H.2618
2.2.2 H.26311
2.2.3 H.263+16
2.2.4 MPEG系列19
第三章 視訊傳輸錯誤、保護與錯誤遮隱技術23
3.1 視訊傳輸錯誤23
3.1.1 錯誤對視訊編碼資料流的影響23
3.1.2錯誤對不同編碼畫面的影響25
3.2 視訊傳輸保護27
3.3 錯誤遮隱技術28
3.3.1 時間域錯誤遮隱法28
3.3.2 空間域錯誤遮隱法35
3.3.3 頻域錯誤遮隱法39
3.3.4 整合域錯誤遮隱法40
第四章 整合時間域與空間域錯誤遮隱法42
4.1 時間域分割區塊匹配遮隱法42
4.1.1邊界匹配法以及經修改的邊界匹配法的優缺點42
4.1.2 移動向量的匹配44
4.1.3 區塊分割與移動向量回復46
4.2 空間域改良式最接近像素內插法48
4.2.1空間域法的共通缺點48
4.2.2改良式最接近像素內插法49
4.3 整合時間域與空間域錯誤遮隱法50
4.4 畫面區塊回復順序52
第五章 實驗模擬結果與討論54
5.1 實驗模擬環境說明54
5.1.1 輸入影像格式54
5.1.2 視訊壓縮模擬參數54
5.1.3 有雜訊干擾傳輸環境的說明55
5.1.4 模擬錯誤情況的說明56
5.2 實驗模擬結果58
5.3 實驗結果討論64
第六章 結論與未來展望66
參考文獻68

[1]http://www.jpeg.org/[2]http://www.mpeg.org/[3]http://www.itu.int/ITU-T/[4]W. M. Lam, A. R. Reibman, and B. Liu, “Recovery of lost or erroneously received motion vectors,” IEEE Conf. on Acoustics, Speech, and Signal Processing, pp. V417-V420, Minnesota, USA, April 1993.[5]H. Ahmed, J. Narajan, and S. Rao, “Discrete cosine transform,” IEEE Trans. , vol. 23, pp. 90-93, 1974.[6]ITU-T Recommendation H.261: Video Codec for audiovisual services at p □ 64 kbits, ITU, Mar. 1993.[7]Draft ITU-T Recommendation H.263: Video Coding for Low Bitrate Communication, ITU, May 1996.[8]ITU-T Recommendation H.263: Video Coding for Low Bitrate Communication, ITU, Feb. 1998.[9]ISO/IEC DIS 13818-2: Information technology — Generic coding of moving pictures and associated audio information — Part 2: Video, 1994.[10]M. Ghanbari, “Two-layer coding of video signals for VBR networks,” IEEE J. Select. Areas Commun., vol. 7, pp. 801—806, June 1989.[11]Q.-F. Zhu, Y. Wang, and L. Shaw, “Coding and cell loss recovery for DCT-based packet video,” IEEE Trans. Circuits Syst. Video Technol., vol. 3, pp. 248—258, June 1993.[12]N. T. Cheng and N. G. Kingsbury, “The EREC: An efficient error resilient technique for encoding positional information on sparse data,” IEEE Trans. Commun., vol. 40, pp. 140—148, Jan. 1992.[13]D. W. Redmill and N. G. Kingsbury, “The EREC: An error resilient technique for coding variable-length blocks of data,” IEEE Trans. Image Processing, vol. 5, pp. 565—574, Apr. 1996.[14]Q. Zhang and S. A. Kassam, “Adaptive hybrid ARQ/FEC protocols for low-bit-rate video over wireless channels,” Proc. of IEEE Conf. Inform. Sciences Syst., Princeton, NJ. March 1996.[15]H. Liu, Q. Zhang, M. El Zarki, and S. A. Kassam, “Wireless video transmission with adaptive error control,” Proc. of IEEE Int. Symp. Inform. Theory Application, Victoria, B.C. Canada. March 1996.[16]A. Narula and J. Lim, “Error concealment techniques for an all-digital high-definitiontelevision system,” SPIE Visual Communication and Image Processing, pp. 304-315, Nov. 1993.[17]W. Keck, “A method for robust decoding of erroneous MPEG-2 video bitstreams.” IEEE Trans. Consumer Electronics, vol. 42, no. 3, pp. 411-421, 1996.[18]S. J. Won and H. Y. Sung, “Directional interpolation for spatial error concealment,” Proc. of Int. Conf. on Consumer Electronics, pp. 26-27, 1997.[19]S. J. Won and H. Y. Sung, “Error concealment based on directional interpolation,” IEEE Trans. Consumer Electronics, vol. 43, no. 3, pp. 295-302, 1997.[20]J. Feng, K. T. Lo, and H. Mehrpour, “Error concealment for MPEG video transmissions,” IEEE Trans. Consumer Electronics, vol. 43, no. 2, May 1997.[21]M. J. Chen, L. G. Chen, and R. M. Weng, “Error concealment of lost motion estimation vectors with overlapped motion compensation,” IEEE Trans. Circuits and Syst. for Video Technol., vol. 7, no. 3, pp. 560-563, June 1997.[22]S. Tsekeridou, I. Pitas, and C. Le Buhan, “An error concealment scheme for MPEG-2 coded video sequences,” Proc. of IEEE Int. Symposium on Circuits and Systems, vol. 2, pp. 1289-1292, 1997.[23]Z. Wang, Y. Yu and D. Zhang, “Best neighborhood matching: an information loss restoration technique for block-based image coding systems,” IEEE Trans. Image Processing, pp. 1056-1061, July 1998.[24]M. Ghanbari and V. Seferidis, “Cell-loss concealment in ATM video codecs,” IEEE Trans. Circuits and Systems for Video Technol., vol. 3, no. 3, June 1993.[25]S. Aign and K. Fazel, “Temporal and spatial error concealment techniques for hierarchical MPEG-2 video codec,” Proc. of IEEE Int. Conf. on Commun., vol. 3, pp. 1778-1783, 1995.[26]B. Ramamurthi and A. Gersho, “Nonlinear space-variant postprocessing of block coded images,” IEEE Trans. Acoustics, Speech, and Signal Processing, vol. ASSP-34, no. 5, pp.1258-1267, Oct. 1968.[27]W. Kwok and H. Sun, “Multi-directional interpolation for spatial error concealment,” IEEE Trans. Consumer Electronics, vol. 39, no. 3, pp. 455 — 460, 1993.[28]H. Sun, K. Challapali, and J. Zdepski, “Error concealment in digital simulcast AD-HDTV decoder,” IEEE Trans. Consumer Electronics, vol. 38, no. 3, Aug. 1992.[29]S. Shirani, F. Kossentini, and R. Ward, “A clocealment method for video communications in an error-prone environment,” IEEE Journal on Selected Areas in Commun., vol. 18, no. 6, pp. 1122-1128, June 2000.[30]L. Atzori, F. G. B. D. Natale, and C. Perra, “A spatio-temporal concealment technique using boundary matching algorithm and mesh-based warping (BMA-MBW),” IEEE Trans. on Multimedia, vol. 3, no. 3, Sept. 2001.[31]Source code for H. 263 TMN encoder (based on the Test Model Near-term (TMN8) in the ITU-T LBC Expert Group), UBC Image Processing Laboratory, University of British Columbia, Canada, 1997.[32]R. Zhang, L. Regunathan, and K. Rose, “Video coding with optional Inter/Tntra-mode switching for packet loss resilience,” IEEE J. on Selected Areas in Commun., vol. 18, no. 6, pp. 966-976, 2000.[33]A. Ravindran, H. Liu, I. Agoren, A.Lackpour, D. Miller, M. Kavehrad, J. Doherty, “Mobile multimedia services for third generation communications systems,” Proc. of IEEE Vehicular Technol. Conf., vol. 4, pp. 2589-2593, 2001.[34]Q. Zhu, Y. Wang and L. Shaw, “Coding and cell-loss recovery in DCT-based packet video,” IEEE Trans. Circuits and Systems for Video Technol., vol. 3, no. 3, June 1993.