Proposed Error Concealment Research Articles

Error Concealment for 3-D DWT Based Video Codec Using Iterative Thresholding

Error concealment for video coding based on a 3-D discrete wavelet transform (DWT) is considered. We assume that the video sequence has a sparse representation in a known basis different from the DWT, e.g., in a 2-D discrete cosine transform basis. Then, we formulate the concealment problem as $l_{1}$ -norm minimization and solve it utilizing an iterative thresholding algorithm. Comparing different thresholding operators, we show that video block-matching and 3-D filtering provide the best reconstruction by utilizing spatial similarity within a frame and temporal similarity between neighbor frames. Experimental results show that the proposed error concealment provides up to 6-dB improvement in the peak signal-to-noise ratio in comparison with existing recovery methods.

Depth Image Compression and Error Concealment for 3D Video Communication

In this paper, an error concealment scheme for neural-network based compression of depth image in 3D videos is proposed. In the neural-network based compression, each depth image is represented by one or more neural networks. The advantage of neural-network based compression lies in the parallel processing ability of multiple neurons, which can handle the massive data volume of 3D videos. The similarity of neuron weights of neighboring nodes is exploited to recover the loss neuron weights when transmitting with an error-prone communication channel. With a simulated noisy channel, the quality of compressed 3D video, which is reconstructed undergoing the noisy channel, can be recovered well by the proposed error concealment scheme.

Recovery of Lost Motion Vectors Using Encoded Residual Signals

Motion-vector-based error concealment algorithms recover lost blocks by motion compensation with the estimated motion vectors. Traditionally, the estimated motion vectors for the lost block are derived by the direct usage of the neighboring available motion vectors. In this work, the residual signal in a block encoded in the video bitstream is used to measure the reliability of the corresponding motion vector. The residual information is applied to weight the neighboring available motion vectors differently, to further improve a newly proposed mathematical formulation between encoded motion vectors and extrapolated motion vectors. The proposed error concealment method using the residual information outperforms a state-of-the-art error concealment algorithm by up to 2.12 dB in sequence PSNR, and outperforms a classic DMVE method by up to 8.27 dB.

Packet Video Error Concealment With Auto Regressive Model

In this paper, auto regressive (AR) model is applied to error concealment for block-based packet video coding. In the proposed error concealment scheme, the motion vector for each corrupted block is first derived by any kind of recovery algorithms. Then each pixel within the corrupted block is replenished as the weighted summation of pixels within a square centered at the pixel indicated by the derived motion vector in a regression manner. Two block-dependent AR coefficient derivation algorithms under spatial and temporal continuity constraints are proposed respectively. The first one derives the AR coefficients via minimizing the summation of the weighted square errors within all the available neighboring blocks under the spatial continuity constraint. The confidence weight of each pixel sample within the available neighboring blocks is inversely proportional to the distance between the sample and the corrupted block. The second one derives the AR coefficients by minimizing the summation of the weighted square errors within an extended block in the previous frame along the motion trajectory under the temporal continuity constraint. The confidence weight of each extended sample is inversely proportional to the distance toward the corresponding motion aligned block whereas the confidence weight of each sample within the motion aligned block is set to be one. The regression results generated by the two algorithms are then merged to form the ultimate restorations. Various experimental results demonstrate that the proposed error concealment strategy is able to improve both the objective and subjective quality of the replenished blocks compared to other methods.

Efficient Spatial-Temporal Error Concealment Algorithm and Hardware Architecture Design for H.264/AVC

This paper presents an efficient error concealment algorithm for video bitstream over error-prone channel suffering from damage. Moreover, hardware architecture design and chip implementation of the proposed error concealment algorithm are also presented. For spatial error concealment, a mode selection algorithm considering the reuse of intra mode information embedded in bitstream is developed for the adaptation of bilinear and directional interpolation. It suffers only 0.08 dB video quality drop in average but the speedup measured on a general purpose processor is up to 40 times compared with the conventional methods. It is also more suitable for low cost hardware design. For temporal error concealment, the decoded motion vectors of the neighboring blocks of the corrupted macroblock are reused to provide hints to estimate the motion vector of the corrupted macroblock. Moreover, for real-time applications, a data and computational results reuse scheme of motion vector estimation is proposed and 96% computation and memory bandwidth can be reduced compared with the conventional methods with 0.18 dB quality drop in average. With the UMC 90 nm 1P9M process, the proposed error concealment engine can process HDTV1080P 30 frames per second video data and the power consumption is 15.77 mW at 125 MHz operation frequency.

Concealment of Whole-Picture Loss in Hierarchical B-Picture Scalable Video Coding

H.264/AVC scalable video coding (H.264/AVC SVC), as the scalable extension of H.264/AVC, offers the flexible adaptivity in terms of spatial, temporal and SNR scalabilities for the generated bitstream. However, such compressed video still suffers from the bad playback quality when packet loss occurs over unreliable networks. In this paper, we present an error concealment algorithm to tackle the whole-picture loss problem in H.264/AVC SVC when hierarchical B-picture coding is used to support temporal scalability. In the proposed algorithm, by taking advantage of the temporal relationship among the adjacent video pictures, the motion information of the lost picture is derived simply and efficiently based on the principle of temporal direct mode. Utilizing the derived motion information, the lost picture is concealed by performing motion compensation on the correctly received temporally previous and future video pictures. The experimental results demonstrate that as a post-processing tool, the proposed error concealment algorithm is able to significantly improve both the objective and subjective qualities of the decoded video pictures in the presence of packet losses when compared to the error concealment algorithm used in H.264/AVC SVC reference software. The proposed method can also be applied to H.264/AVC with hierarchical B-picture coding for error concealment.

Error concealment aware streaming video system over packet-based mobile networks

A compressed video bitstream is extremely sensitive to errors when it is transmitted via networks with bursty packet loss such as 3G and mobile WiMAX. Error concealment techniques have been used to improve the recovered picture quality in cases in which parts of the coded picture are not available at the decoder for reconstruction. However, most conventional error concealment methods show low image reconstruction performance due to unavailable motion information about image blocks during burst packet loss, and require high energy consumption to find the best error concealment method in the receiver. The proposed error concealment aware error resilient streaming video system has an intelligent error concealment selector. The method recommends the best error concealment method per macroblock, by additionally transmitting its error concealment selection codes to the decoder. The streaming client conceals the corrupted MB via the chosen error concealment method, with low energy consumption, even when the frame loss is bursty. The experimental results show that the system is highly effective, in terms of the video quality and energy consumption, at the cost of a slight overhead for transmitted bit streams.

Image Error Concealment Using Watermarking with Subbands for Wireless Channels

Transmission of block-coded images through error-prone wireless channels often results in lost blocks. In this study, we investigate a novel error concealment method for covering up these high packet losses and reconstructing a close approximation. Our scheme is a modified discrete wavelet transform (DWT) technique (namely, subbands based image error concealment (SIEC)) for embedding downsized replicas of original image into itself. We propose that this technique can be implemented for wireless channels to combat degradations in a backward-compatible scheme. We show that the proposed error concealment technique is promising, especially for the erroneous channels causing a wider range of packet losses, at the expense of computational burden