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Overview
The availability of inexpensive
hardware such as CMOS cameras and
microphones has fostered the development of Wireless Multimedia
Sensor Networks (WMSNs), i.e., networks of wirelessly interconnected
devices that are able to ubiquitously retrieve multimedia content
such as video and audio streams, still images, and scalar sensor
data from the environment. In this project, we shall first survey the
state of the art in
algorithms, protocols, and hardware for wireless multimedia sensor
networks and identify open research
issues. In the course of this process, we shall evaluate existing
solutions and open
research issues at the application, transport, network, link, and
physical layers of the communication stack, along
with possible cross-layer synergies and optimizations. This ultimately
forms the groundwork for our
interest in developing an optimally efficient suite of multimedia
communication protocols. We envisage
a cross-layered approach that may combine, under one umbrella, recent
advances in coding, multi-channel
MAC protocols, emerging technologies like UWB, amongst others.
The first step in creating a WMSN is equipping a
single sensor device with audio and visual
information collection modules. As an example, the Cyclops image
capturing and inference module, is designed for
extremely light-weight imaging and can be interfaced with a host
mote such as Crossbow's MICA2 or MICAz. In addition to the ability
to retrieve multimedia data, WMSNs will also be able to store,
process in real time, correlate and fuse multimedia data originated
from heterogeneous sources. Wireless multimedia sensor networks will
not only enhance existing
sensor network applications such as tracking, home automation, and
environmental monitoring, but they will also enable several new
applications such as:
- Multimedia Surveillance Sensor Networks. Video
and audio sensors will be used to enhance and complement
existing surveillance systems against crime and terrorist attacks.
Large scale networks of video sensors can extend the ability of law
enforcement agencies to monitor areas, public events, private
properties and borders.
- Traffic Congestion Avoidance Systems. It will
be possible
to monitor car traffic in big cities or highways and deploy services
that offer traffic routing advice to avoid congestion. Automated
parking assistance is another
possible related application.
- Advanced Health Care Delivery. Telemedicine
sensor networks can be integrated with
3G multimedia networks to provide ubiquitous health care services.
Patients will carry medical sensors to monitor parameters such as
body temperature, blood pressure, pulse oximetry, ECG, breathing
activity. Similarly, elderly and family monitors will help in providing
timely and essential
support to the less able sections of society.
- Industrial Process Control Multimedia content
such as imaging, temperature, or
pressure amongst others, may be used for time-critical industrial
process control. The integration of machine vision systems with
WMSNs can
simplify and add flexibility to systems for visual inspections and
automated actions that require high-speed, high-magnification, and
continuous operation.
Many of the above applications require the sensor network paradigm
to be re-thought in view of the need for mechanisms to deliver
multimedia content with a certain level of quality of service (QoS).
Since the need to minimize the energy consumption has driven most of
the research in sensor networks so far, mechanisms to efficiently
deliver application-level QoS, and to map these requirements to
network-layer metrics such as latency and jitter, have not been
primary concerns in mainstream research on sensor networks.
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