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21
Wireless sensor network
- Technology Information of China
"... Numerous micro-devices are interconnected in Wireless Multimedia Sensor Networks (WMSNs), such as surveillance. While due to view field of these multimedia sensors is oriented, blind spots caused by an occlusion is unavoidable, which will impact on surveillance service quality. For reducing this aff ..."
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Numerous micro-devices are interconnected in Wireless Multimedia Sensor Networks (WMSNs), such as surveillance. While due to view field of these multimedia sensors is oriented, blind spots caused by an occlusion is unavoidable, which will impact on surveillance service quality. For reducing this affection and figuring out a real sensing area, detailed formulas are given in this paper to compute real points. Four steps are designed to detect salient area, which act as potential obstacles. After that, an algorithm utilizing rectangle to approximate the detected areas is proposed, which consider hemline as an intersecting line between earth and objects. Then using this intersecting line as a benchmark, a maximum prism container is employed to find out the blind area. Experiments show that even for monocular image, this algorithm can efficiently find out the real view field of nodes. In addition, by considering physical obstacles in wireless multimedia sensors, this paper contributes to 3D field of view study.
A Survey on Multimedia-Based Cross-Layer Optimization in Visual Sensor Networks
- SENSORS
, 2011
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Article Adaptive Redundant Speech Transmission over Wireless Multimedia Sensor Networks Based on Estimation of Perceived Speech Quality
, 2011
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An OMNeT++ Framework to Evaluate Video Transmission in Mobile Wireless Multimedia Sensor Networks
, 2013
"... The development and evaluation of new algorithms and protocols for Wireless Multimedia Sensor Networks (WMSNs) are usually supported by means of a discrete event network simulator, where OMNeT++ is one of the most important ones. However, experiments involving multimedia transmission, video flows wi ..."
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Cited by 4 (3 self)
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The development and evaluation of new algorithms and protocols for Wireless Multimedia Sensor Networks (WMSNs) are usually supported by means of a discrete event network simulator, where OMNeT++ is one of the most important ones. However, experiments involving multimedia transmission, video flows with different characteristics, genres, group of pictures lengths, and coding techniques must be evaluated based also on Quality of Experience (QoE) metrics to reflect the user’s perception. Such experiments require the evaluation of video-related information, i.e., frame type, received/lost, delay, jitter, decoding errors, as well as inter and intra-frame dependency of received/distorted videos. However, existing OMNeT++ frameworks for WMSNs do not support video transmissions with QoE-awareness, neither a large set of mobility traces to enable evaluations under different multimedia/mobile situations. In this paper, we propose a Mobile MultiMedia Wireless Sensor Network OMNeT++ framework (M3WSN) to support transmission, control and evaluation of real video sequences in mobile WMSNs.
A Routing Mechanism Based on the Sensing Relevancies of Source Nodes for Time-Critical Applications in Visual Sensor Networks
"... Abstract — Wireless sensor networks may be deployed to retrieve visual information from the monitored field, enriching monitoring and control applications. Whenever a set of cameraenabled sensor nodes are deployed for time-critical monitoring, visual information as still images and video streams may ..."
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Abstract — Wireless sensor networks may be deployed to retrieve visual information from the monitored field, enriching monitoring and control applications. Whenever a set of cameraenabled sensor nodes are deployed for time-critical monitoring, visual information as still images and video streams may need to reach the sink as soon as possible, requiring a differentiated treating of the network when compared with non-critical visual data. In such way, considering that source nodes may have different sensing relevancies for the application, according to the desired monitoring tasks and the current sensors ’ poses and fields of view, we propose a delay-aware multihop routing mechanism where higher relevant visual data packets are routed through paths with lower end-to-end delay. As sensor nodes are expected to be energy-constrained, transmitting only highrelevant packets through shorter/faster paths may prolong their lifetime and assure longer time-critical delivering, with low impact to the overall monitoring quality. Keywords — Multihop routing; Energy-efficiency; Sensing relevance; Time-critical transmission; Visual sensor networks.
Architecture and Protocol of a Semantic System Designed for Video Tagging with Sensor Data in Mobile Devices
, 2012
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A Discrete Wavelet Transform (DWT)-Based Energy-Efficient Selective Retransmission Mechanism for Wireless Image Sensor Networks
, 2012
"... Source nodes in wireless image sensor networks transmit much more information than traditional scalar sensor networks, thereby demanding more energy of intermediate relaying nodes and putting energy efficiency as a key design issue. Intermediate nodes are usually interconnected by error-prone link ..."
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Cited by 3 (3 self)
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Source nodes in wireless image sensor networks transmit much more information than traditional scalar sensor networks, thereby demanding more energy of intermediate relaying nodes and putting energy efficiency as a key design issue. Intermediate nodes are usually interconnected by error-prone links where bit-errors are common, potentially degrading the application monitoring quality. When reliability is assured by retransmission mechanisms, higher packet error rates do not affect the application quality but result in additional energy consumption due to packet retransmission, even though many monitoring applications can tolerate some loss in the quality of the received image. DWT coding can decompose an image in data subbands, each one with different relevancies for the reconstruction of the original image at the receiver side. We propose an energy-efficient selective hop-by-hop retransmission mechanism where the reliability level of each packet is a function of the relevance of the payload data, according to the resulting subbands and the number of times a 2D DWT is applied over the images captured by the sensors ’ cameras. In so doing, some lost packets are not retransmitted, saving energy of intermediate nodes with low impact to the quality of the reconstructed images. In order to estimate the benefits of this tradeoff between energy consumption and image quality, we designed a comprehensive energy consumption model and applied it in extensive
Current Trends in Wireless Mesh Sensor Networks: A Review of Competing Approaches
, 2013
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Research Trends in Wireless Visual Sensor Networks When Exploiting Prioritization
- SENSORS
, 2015
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