During transmitting encoded digital video sequences over noisy communication channels, the information of the images will be lost. An error concealment method based on robust optical flow is proposed, as a post-processing tool at the decoder side to solve this problem. The property of optical flow technique on efficiently obtaining motion estimation is used to recover the lost block in pixel-wise manner. This processing not only avoids the image blurring, but also reduces the blocking effect. In the estimation of optical flow, the relation between data conservation term and spatial coherence term of the objective function is adaptively adjusted. In order to increase the robustness, Lorentzian function is used to construct the energy function. Simulation results show that the proposed method can recover the higher quality image on both subjective visual evaluation and objective numerical metrics, comparing to the existing error concealment methods.
Wang Y, Zhu Q F. Error control and concealment for video communication: A review[J].Proc. IEEE.1998, 86(5):974-997[2]Wang Y, Zhu Q F, Shaw L. Maximally smooth image recovery in transform coding[J].IEEE Trans. on Communications.1993, 41(10):1544-1551[3]Sun H, Kwok W. Concealment of damaged block transform coded images using projections onto convex sets[J].IEEE Trans. on Image Processing.1995, 4(4):470-477[4]Salama P, Shroff N B, Delp E J. Error concealment in MPEG video streams over ATM networks[J].IEEE J. on Selected Areas Communications.2000, 18(6):1129-1144[5]Sun H, Challapali K, Zdepski J. Error concealment in digital simulcast AD-HDTV decoder[J].IEEE Trans. on Consumer Electronics.1992, 38(3):108-116[6]Lam W M, Reilbman A R, Liu B. Recovery of lost or erroneously received motion vectors. ICASSP, Apr. 1993, 5: V417-V420.[7]Horn B K P, Schunck B G. Determining optical flow[J].Artificial Intelligence.1981, 17:185-203[8]Barron J, Beauchemin S, Fleet D. Performance of optical flow techniques. Intl J. Computer Vision, 1994, 12(1): 43-77.[9]Ye M, Haralick R M, Shapiro L G. Estimating piecewise-smooth optical flow with global matching and graduated optimization[J].IEEE Trans. on Pattern Analysis and Machine Intelligence.2003, 25(12):1625-1630