Gengkun Wang

Frame Loss Concealment for Multiview Video Transmission Over Wireless Multimedia Sensor Networks

In multiview video (MVV) transmission over wireless multimedia sensor networks (WMSNs), a highly compressed video stream is very susceptible to whole-frame losses due to wireless channel errors. Currently, most frame concealment methods can only handle 2-D video or 3-D video with depth, since a lost motion vector can be recovered utilizing the relationship between the color frames and their corresponding depth map. However, depth generation is infeasible in the scenario of WMSNs due to energy constraints and computational limitations of low-power video sensor nodes. In this paper, we tackle the problem of concealing lost whole frames for multiview 3-D video transmission over WMSNs. We propose a new technique, which is capable of dealing with this important problem without the aid of depth map. Experimental results are presented to demonstrate that the proposed algorithm is able to effectively conceal frames of MVV and significantly outperforms other techniques in both objective and subjective quality measurements.

Outage Analysis of Non-Regenerative Analog Network Coding for Two-Way Multi-Hop Networks

We investigate the performance of analog network coding (ANC) for multi-hop networks in this letter. With the amplify-and-forward (AF) protocol, relays broadcast the sum of two colliding signals to neighboring nodes, while the source node can subtract its own signal from the colliding signals to obtain the received information. We first give the transmission scheme expressions for the n-node m-frame two-way multi-hop network. For this scheme, we derive the end-to-end signal-to-noise ratio (SNR) expression. The closed-form expression of the outage probability for the generalized multi-hop network is evaluated. Numerical results demonstrate that the outage performance with ANC is better than that of the traditional AF scheme.

Light Field Multi-View Video Coding With Two-Directional Parallel Inter-View Prediction

Light field (LF) technology has been popularly adopted by a wide range of conventional industries. However, one problem when dealing with LFs is the sheer size of data volume. There have been many multi-view video coding (MVC)-based LF video coding methods reported in the literature, aiming at finding the best prediction structure for LF video coding. It is clear that the number of possible prediction structures is unlimited, and it is also observed that the coding bit-rate can be reduced by increasing the number of bi-directionally encoded views in the prediction structure. However, none work has been conducted to analyze the relationship of the prediction structure with its coding performance. In light of this observation, we first design a new LF-MVC prediction structure by extending the inter-view prediction into a two-directional parallel structure. Analytical models for source coding rate and encoding time are developed to analyze their relationships with the prediction structure, and are proven to be well-matched to our experimental results. Experimental evaluation of two LF video sequences demonstrates that the proposed LF-MVC prediction structure can achieve a factor of 26% bit-rate reduction against the conventional MVC prediction structure for an LF video with 5 × 5 views, and a further 34% bit-rate reduction for an LF video with a larger 10 × 10 views. Compared with the state-of-the-art MVC-based LF video coding prediction structures in the literature, LF-MVC can achieve the best coding performance, and with its high encoding efficiency, is well suited for deployment in practical LF-based 3D systems.

Big video data for light-field-based 3D telemedicine

Big data and 3D technologies have been successfully leveraged in a variety of industries to improve their efficiency and quality. The healthcare sector has lagged in the uptake of these new technologies. In this article, we propose a novel light field (LF)-based 3D telemedicine system. The proposed system is able to provide a life-like tele-consultation experience that provides a quality of experience far beyond conventional 2D telemedicine systems. In addition, its embedded 3D data in light field video (LFV) format can also facilitate a higher level of big data analysis, so-called big LFV data analysis. To solve the challenges in storage and analysis of LFV, we extend the standard multi-view video coding (MVC) approach to LF-MVC, which is able to achieve up to a 23 percent higher compression rate when compared to standard MVC. Furthermore, a big data analysis framework is proposed to integrate LFV into conventional telemedicine analysis, which can achieve improved classification, statistics gathering, prediction, and cognitive analysis for healthcare applications.

Generalized Wireless Network Coding Schemes for Multihop Two-Way Relay Channels

Due to the overwhelming complexity of multihop transmission and intermessage interference, only a limited amount of research has been carried out in the implementation of wireless network coding (WNC) for generalized multihop two-way relay channels (MH-TRCs), let alone the generalization of multihop WNC (MH-WNC) schemes. Our recent paper has showed that the MH-WNC scheme with fixed two transmission time intervals (TTIs) was unable to always outperform conventional non-NC schemes in outage performance for the MH-TRC with an arbitrary number of nodes. In view of this fact, a generalized MH-WNC scheme with multiple TTIs is designed for the L-node K-message MH-TRC in this paper. Closed-form expressions for the upper bound of the outage probability for two prominent relaying network coding strategies (i.e., analog network coding and compute-and-forward network coding) are derived. Moreover, by investigating the relationships between the outage probability and the numbers of nodes, messages, and TTIs, we obtain an optimal MH-WNC scheme that can achieve the best outage probability and always outperform non-NC in the MH-TRC with an arbitrary number of nodes.

Outage performance of analog network coding in generalized two-way multi-hop networks

We investigate the performance of analog network coding (ANC) for multi-hop networks in this paper. With the amplify-and-forward (AF) protocol, relays broadcast the sum of two colliding signals to neighboring nodes, while the source node can subtract its own signal from the colliding signal to obtain the received information. We first give the transmission scheme expressions for the n-node m-frame two-way multi-hop network. For this scheme, we derive the end-to-end signal-to-noise ratio (SNR) expression. Without loss of generality, the closed-form expression of the outage probability for the generalized multi-hop network is evaluated. Numerical results demonstrate that the outage performance with ANC is better than the traditional scheme without ANC.

Generalized Compute-and-Forward Schemes for Multi-Hop Two-Way Relay Channels

Wireless network coding for multi-hop two-way relay channels (MH-TRC) has been proven to achieve a significantly improved network throughput than non- network coding (Non-NC) schemes. Our previous work showed that the multi-hop compute-and-forward (MH- CPF) scheme for the MH-TRC with fixed two transmission time intervals was unable to outperform Non-NC in the MH-TRC with an arbitrary number of nodes. In view of this fact, we propose an I-time- interval (I-TI) MH-CPF scheme (I represents the number of transmission time intervals) for the MH- TRC with arbitrary numbers of nodes and messages. By converting the transmission pattern to a corresponding characteristic matrix, the outage probability of the I-TI MH-CPF scheme is derived. We investigate the relationships between the numbers of nodes, messages and TIs with the outage probability. It is proven that L-1-TI MH-CPF can outperform 2-TI MH-CPF when the number of messages is large, while the MH-CPF scheme with a larger number of TIs has better outage performance than 2-TI MH-CPF in the MH-TRC with a small number of nodes.

Design of a wireless portable vibration acquisition and analysis instrument

In this paper, we propose a new approach for the design of a wireless portable vibration acquisition and analysis instrument. The system can achieve high-speed synchronous data acquisition at the sample speed of 10k samples per second per channel. The system employs Wireless LAN technology to achieve data transmission up to 54 Mbps. A remote signal analysis scheme based on an embedded system is proposed, which is achieved via the wireless connection between the online monitoring diagnosis system and the portable instrument. A novel curve display module with two-finger touching zooming technique is employed. The user interface operates under the Windows CE embedded operation system.