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Engineering Energy Efficient visual sensor Network Applications Using Skeletons

INTERNATIONAL JOURNAL OF PARALLEL PROGRAMMING 2014年第4期42卷 663-680页

作者： Chessa, Stefano Pelagatti, Susanna Triolo, Nicoletta Univ Pisa Dipartimento Informat Pisa Italy

visual sensor networks (VSNs) perform complex scene analysis algorithms that require significant computations and communications. Under this respect, the use of skeletons contributes to reduce the complexity of VSN programming and may ensure an easier and better optimization of the code. In this context, we propose INS, a stencil based skeleton targeted for wireless/visual sensor networks (W/VSNs) and give a preliminary analysis of its benefits using tracking as a case study. INS abstracts a distributed approximation schema in which the estimation of a given metric is organized in a sequence of steps. Each step includes collecting estimates from some neighbor nodes and local computation of a new approximation. In particular, INS takes inspiration from some stencil based skeletons proposed for parallel computation and merges it with the classical event driven model typical of sensor programming. As a result, the execution of each step is triggered by the detection of a relevant event in the environment. Tracking consists in periodically predicting position and velocity of one or more mobile targets. We discuss how INS can be instantiated to a distributed version of Kalman filtering. As energy efficiency is central in W/VSNs, we derive analytic models for energy dissipation of the INS skeleton depending on different concepts of neighborhood for the data exchanged at each step. Then, these models are used to guide the deployment of our tracking application on a real scenario.

关键词： visual sensor networks Algorithmic skeletons Energy saving Kalman filtering

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Uplink Scheduling of visual sensors: When View Popularity Matters

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IEEE TRANSACTIONS ON COMMUNICATIONS 2015年第2期63卷 510-519页

作者： Chakareski, Jacob Univ Alabama Dept Elect & Comp Engn Tuscaloosa AL 35487 USA

Decentralized camera sensors capture a 3D scene of interest from multiple perspectives. The captured video signals need to be transmitted to a central station over a shared wireless channel. A collocated server streams the gathered data to a collection of clients interested in experiencing the scene interactively. We design a constrained optimization framework for sharing the transmission bandwidth of the wireless channel across the sensors such that the average video quality over the client population is maximized. We consider scheduling the uplink resources of the wireless channel at the view or packet level. In the first case, the central station partitions the channel capacity across a select subset of views that are transmitted entirely. In the second case, the station coordinates the packet transmissions of every sensor. We formulate exact and approximate algorithms to solve the optimization of interest. We examine their transmission efficiency via simulation experiments that demonstrate considerable gains over the state-of-the-art and study the impact of view popularity.

关键词： Immersive communication rate-distortion optimization view-popularity-driven uplink scheduling visual sensor networks

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A Study on the Impact of Multiview Distributed Feature Coding on a Multicamera Vehicle Tracking System at Roundabouts

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IEEE ACCESS 2022年 10卷 39502-39517页

作者： Eleuch, Salma Khouja, Nadia Milani, Simone Erseghe, Tomaso Tlili, Fethi Univ Carthage Higher Sch Commun Tunis SUPCOM GRESCOM Lab Carthage 1054 Tunisia Univ Padua Dipartimento Ingn Informaz I-35131 Padua Italy

visual sensor networks are one potential enabler for the evolution of the Internet of things. Due to their limited resources in terms of energy and bandwidth, it is crucial to identify appropriate approaches that take into considerations such constraints and reduce the amount of data transmitted to the gathering point (sink). In this context, this paper describes the impact of a distributed smart-camera system that exploits an analyze-then-compress strategy, on a multi-view vehicle tracking at roundabouts application. In the tested system, part of the processing is shifted to the smart cameras, i.e., the object detection/classification and feature extraction, so that only the extracted features describing moving vehicles are transmitted instead of the whole image/video. Features are further compacted by using a state-of-the-art distributed coding technique, based upon an efficient clustering method that exploits the temporal and spatial (multiple views) correlations between features. The system is tested on a real-data scenario, by evaluating the bit-rate reduction capabilities in dependence of the channel conditions, as well as the matching accuracy of the reconstructed descriptors in the specific tracking application. Both feature-wise and object-wise matching are investigated. For the chosen application scenario, a bit-rate reduction of 30 - 35% is proved to be achievable in non-ideal channel conditions. Even more interestingly, such reduction is proved not to harm the matching accuracy (i.e., it is coherent with the target application), for which an F-score up to 0.923 is guaranteed.

关键词： Bit-rate reduction distributed feature coding feature matching multi-view resource allocation roundabouts smart city traffic monitoring vehicle tracking visual sensor networks

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Memory-efficient architecture for FrWF-based DWT of high-resolution images for IoMT applications

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MULTIMEDIA TOOLS AND APPLICATIONS 2021年第7期80卷 11177-11199页

作者： Tausif, Mohd Jain, Abhinandan Khan, Ekram Hasan, Mohd Univ Beira Interior Fac Engn Dept Informat Covilha Portugal MIT Mit Media Lab Cambridge MA USA Aligarh Muslim Univ ZH Coll Engg Dept Elect Engg Aligarh Uttar Pradesh India

This paper proposes a simple low memory architecture for computing discrete wavelet transform (DWT) of high-resolution (HR) images on low-cost memory-constrained sensor nodes used in visual sensor networks (VSN) or Internet of Multimedia Things (IoMT). The main feature of the proposed architecture is the novel data scanning technique that makes memory requirement independent of the image size. The proposed architecture needs only (30S) words of memory, where S is the number of parallel processing units and a critical path delay (CPD) equal to the delay of a multiplier (T-m). Furthermore, a multiplierless version of this architecture is also proposed which reduces the CPD to T-a

关键词： Discrete wavelet transform visual sensor networks High-resolution images Image coders Low memory architecture Internet of multimedia things

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A Distributed Rate-Control Approach to Reduce Communication Burdens in VSNs

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IEEE ACCESS 2023年 11卷 1011-1022页

作者： Eleuch, Salma Khouja, Nadia Milani, Simone Erseghe, Tomaso Tlili, Fethi Univ Carthage Higher Sch Commun Tunis SUPCOM GRESCOM Lab El Ghazala Ariana 2083 Tunisia Univ Padua Dipartimento Ingn Informaz Padua 35131 Italy

In visual sensor networks, the analyze-then-compress paradigm, where each camera process data and extract local features, is proved to be an efficient approach to reduce the amount of transmitted information. The bitrate can be further reduced by efficiently compressing the extracted features using a distributed feature coding technique. However, since the rate control is performed at the decoder, an abundant use of the feedback channel is needed to adjust the coding rate. Moreover, transmitting all extracted features, including irrelevant ones with no further contribution to the application accuracy, overloads the network. In this paper, we propose a novel feature selection and distributed coding rate control strategies that cope with these issues. The proposed strategies are designed to significantly reduce the transmitted bitrate and the communication burden with the sink, which implicitly reduces the energy consumption and the decoding delay. We show that, wisely selecting at the camera sensors level only the features effectively contributing to the application accuracy reduces the amount of transmitted information up to 34% while preserving accuracy. Furthermore, the cameras can collaborate periodically, by exchanging small amount of information about their selected features, to estimate the minimum transmission rate required for each feature based on a linear fitting model that takes into consideration the inter-camera correlation and the channel conditions. Significant average bitrate savings, reaching up to 37.71%, are achieved.

关键词： Feature extraction Cameras Encoding Decoding Correlation Bit rate visualization sensors Distributed feature coding rate control feature selection multi-view visual sensor networks

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IEEE TRANSACTIONS ON IMAGE PROCESSING 2014年第1期23卷 56-68页

作者： Katsenou, Angeliki V. Kondi, Lisimachos P. Parsopoulos, Konstantinos E. Univ Ioannina Dept Comp Sci & Engn GR-45110 Ioannina Greece

This paper investigates quality-driven cross-layer optimization for resource allocation in direct sequence code division multiple access wireless visual sensor networks. We consider a single-hop network topology, where each sensor transmits directly to a centralized control unit (CCU) that manages the available network resources. Our aim is to enable the CCU to jointly allocate the transmission power and source-channel coding rates for each node, under four different quality-driven criteria that take into consideration the varying motion characteristics of each recorded video. For this purpose, we studied two approaches with a different tradeoff of quality and complexity. The first one allocates the resources individually for each sensor, whereas the second clusters them according to the recorded level of motion. In order to address the dynamic nature of the recorded scenery and re-allocate the resources whenever it is dictated by the changes in the amount of motion in the scenery, we propose a mechanism based on the particle swarm optimization algorithm, combined with two restarting schemes that either exploit the previously determined resource allocation or conduct a rough estimation of it. Experimental simulations demonstrate the efficiency of the proposed approaches.

关键词： Resource allocation cross-layer optimization DS-CDMA H.264/AVC clustering nash bargaining solution visual sensor networks particle swarm optimization

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visual sensors Hardware Platforms: A Review

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IEEE sensorS JOURNAL 2020年第8期20卷 4025-4033页

作者： Costa, Daniel G. State Univ Feira de Santana Dept Technol BR-44036900 Feira De Santana BA Brazil

In the last two decades, visual sensor networks have been developed to gather visual data from different monitoring scenarios, directly contributing to the maturation of the Internet of Things (IoT) applications landscape. Such developments have evolved according to the releasing of new hardware platforms for the construction of sensor nodes, as well as the availability of low-power compatible cameras. Since sensor networks deployed for visual data sensing are inherently complex and resource-demanding, knowing how visual sensors have been created can give a better perception of how those networks have evolved and which innovations are expected for the next years. This article reviews past developments of visual sensors concerning the employed hardware platforms and cameras, providing a taxonomy for them and discussing how to choose the most appropriate hardware when designing and implementing modern (wireless) visual sensor networks.

关键词： visualization Hardware sensor phenomena and characterization Wireless sensor networks Cameras Performance evaluation sensors hardware platforms visual sensor networks sensors designing camera visual sensing

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visual node module: An open-source extension to the ns-3 network simulator

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INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS 2020年第12期33卷 e4451-e4451页

作者： Mosaif, Afaf Rakrak, Said Cadi Ayyad Univ Lab Appl Math & Comp Sci LAMAI Marrakech Morocco

A wireless visual sensor network is a collective network of directional and battery-operated sensor nodes equipped with cameras. The field of view of these nodes depends on the camera opening angle, its direction, and its depth of view. Therefore, coverage and object detection in this type of networks are more challenging compared with the traditional wireless sensor networks. Thus, many researchers propose algorithms and solutions in this field that need tests and simulations. In this paper, we focus on network simulator 3 (ns-3), which is an open-source and discrete-event tool suitable for wireless network simulation targeted primarily for research and educational use. The lack of models that can simulate visual sensor nodes in this simulator motivated us to design and develop a new visual node module as an extension of the ns-3 core libraries and also to adapt the NetAnim tool to present these nodes graphically. This module will help researchers to simulate, test, and visualize their solutions in wireless visual sensor networks field. In this paper, we present the design and implementation of the proposed module. Furthermore, we show how it can be used in ns-3 to simulate different scenarios of object detection and visualize the results in NetAnim tool.

关键词： coverage network simulation ns-3 object detection target tracking visual sensor networks

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visual sensor Technology for Advanced Surveillance Systems: Historical View, Technological Aspects and Research Activities in Italy

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sensorS 2009年第4期9卷 2252-2270页

作者： Foresti, Gian Luca Micheloni, Christian Piciarelli, Claudio Snidaro, Lauro Univ Udine Dept Math & Comp Sci I-33100 Udine Italy

The paper is a survey of the main technological aspects of advanced visual-based surveillance systems. A brief historical view of such systems from the origins to nowadays is given together with a short description of the main research projects in Italy on surveillance applications in the last twenty years. The paper then describes the main characteristics of an advanced visual sensor network that (a) directly processes locally acquired digital data, (b) automatically modifies intrinsic (focus, iris) and extrinsic (pan, tilt, zoom) parameters to increase the quality of acquired data and (c) automatically selects the best subset of sensors in order to monitor a given moving object in the observed environment.

关键词： Advanced visual surveillance visual sensor networks active vision object detection tracking human behaviour understanding

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Optimal visual sensor placement for coverage based on target location profile

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AD HOC networks 2011年第4期9卷 528-541页

作者： Mostafavi, Seyed Akbar Dehghan, Mehdi Amirkabir Univ Technol Dept Comp Engn & Informat Technol Tehran Iran

The proper placement of visual sensors across a sensor field for covering targets with arbitrary location and orientation is a mission-critical decision in surveillance applications. The specifics of sensor deployment in these applications not only determine the maximum achievable coverage, but it also affects the quality of the target's appearance in cameras for subsequent use in vision tasks. However, the inaccuracies inherent in localization techniques and the lack of knowledge regarding the target orientation render existing proposals insufficient for real-life scenarios. In this paper, we address both challenges. First, we extend the conventional point representation of targets with a circular model to account for full-angle coverage of targets with known location yet with unknown orientation from all directions. We then assume, in the absence of precise location information, a trajectory profile of targets could instead be generated through the importance sampling of the environment, indicating spots where the target is most likely located. This profile-based abstraction enables us to capture the uncertainty in target's location by encircling every agglomeration of proximal samples within one cluster. Each cluster can then be viewed as a virtual macroscopic circular target for which we formulate the coverage problem in terms of a Binary Integer Programming (BIP) model. We have also taken into account the presence of obstruction in between multiple targets by calculating the angles of view of the sensors in an occlusion-dependant manner, effectively determining optimal placement for maximal instead of full-angle coverage. Evaluation results derived from our simulation experiments reveal that the proposed mechanism can effectively achieve high coverage accuracy with minimum number of deployed sensors. (C) 2010 Elsevier B.V. All rights reserved.

关键词： Binary Integer Programming Directional sensor placement Full-angle coverage Circular target model visual sensor networks

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