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  • Reconstruction of lost depth data in multiview video-plus-depth communications using geometric transforms
    Publication . Marcelino, Sylvain; Soares, Salviano; Faria, Sergio; Assunção, Pedro
    This paper addresses depth data recovery in multiview video-plus-depth communications affected by transmission errors and/or packet loss. The novel aspects of the proposed method rely on the use of geometric transforms and warping vectors, capable of capturing complex motion and view-dependent deformations, which are not efficiently handled by traditional motion and/or disparity compensation methods. By exploiting the geometric nature of depth information, a region matching approach combined with depth contour reconstruction is devised to achieve accurate interpolation of arbitrary shapes within lost regions of depth maps. The simulation results show that, for different packet loss rates, up to 20%, the depth maps recovered by the proposed method produce virtual views with better quality than existing methods based on motion information and spatial interpolation. An average PSNR gain of 1.48 dB is obtained in virtual views synthesised from depth maps using the proposed method.
  • Robust decoding of MDC depth maps for enhanced 3D video over hybrid broadcasting networks
    Publication . Marcelino, S.; Correia, P.; Faria, Sergio; Soares, S.; Assunção, Pedro
    This paper addresses the problem of robust decoding of 3D video over hybrid broadcast networks, using Multiple Description Coding (MDC). Despite the fact that MDC allowsdecoding of any description even when the others are lost in the multipath network, the resulting coarsely decoded depth maps produce unacceptable distortion in synthesised views. This is particularly harmful in the case of intra-coded depth slices because of subsequent error propagation. To achieve improved quality in the virtual views synthesised from MDC depth maps received with lost descriptions, a method is proposed based on the depth geometric information extracted from the received descriptions and also from texture motion. Accurate recovery of either lost or coarsely decoded depth slices from one single description, is achieved by jointly using motion information, depth map edges and spatially neighbouring depth values. Comparing with MDC decoding without enhanced reconstruction of lost descriptions, the proposed method reaches quality gains up to 2.29dB for loss rates of 10%.