A visual sensor
network is a network of spatially distributed smart
camera devices capable of
processing and fusing
images of a scene from a
variety of viewpoints into some form more useful than the individual images. A
visual sensor
network may be a type of wireless sensor network, and much of the
theory and application of the latter applies to the former. The network
generally consists of the cameras themselves, which have some local image
processing, communication and storage capabilities, and possibly one or more
central computers, where image data from multiple cameras is further processed
and fused (this processing may, however, simply take place in a distributed
fashion across the cameras and their local controllers). Visual sensor networks
also provide some high-level services to the user so that the large amount of
data can be distilled into information of interest using specific queries.
The primary difference between visual sensor networks and other types of
sensor networks is the nature and volume of information the individual sensors
acquire: unlike most sensors, cameras are directional in their field of view,
and they capture a large amount of visual information which may be partially
processed independently of data from other cameras in the network.
Alternatively, one may say that while most sensors measure some value such as
temperature or pressure, visual sensors measure patterns. In light of
this, communication in visual sensor networks differs substantially from
traditional sensor networks.