A visual sensor network or smart camera network or intelligent camera network is a network of spatially distributed smart camera devices capable of processing, exchanging data 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 Wireless sensor networks (WSNs) refer to networks of spatially dispersed and dedicated sensors that monitor and record the physical conditions of the environment and forward the collected data to a central location. WSNs can measure environmental ...

, 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 An image or picture is a visual representation. An image can be two-dimensional, such as a drawing, painting, or photograph, or three-dimensional, such as a carving or sculpture. Images may be displayed through other media, including a pr ...

, 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.Castanedo, F., Patricio, M. A., García, J., and Molina, J. M. 2006. Extending surveillance systems capabilities using BDI cooperative sensor agents. In Proceedings of the 4th ACM international Workshop on Video Surveillance and Sensor Networks (Santa Barbara, California, USA, October 27 – 27, 2006). VSSN '06. ACM Press, New York, NY, 131–138. DOI= http://doi.acm.org/10.1145/1178782.1178802 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

sensor A sensor is often defined as a device that receives and responds to a signal or stimulus. The stimulus is the quantity, property, or condition that is sensed and converted into electrical signal. In the broadest definition, a sensor is a devi ...

s, cameras are directional in their

field of view The field of view (FOV) is the angle, angular extent of the observable world that is visual perception, seen at any given moment. In the case of optical instruments or sensors, it is a solid angle through which a detector is sensitive to elec ...

, 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.

Applications

Visual sensor networks are most useful in applications involving area

surveillance Surveillance is the monitoring of behavior, many activities, or information for the purpose of information gathering, influencing, managing, or directing. This can include observation from a distance by means of electronic equipment, such as ...

tracking Tracking may refer to: Science and technology Computing * Tracking, in computer graphics, in match moving (insertion of graphics into footage) * Tracking, composing music with music tracker software * Eye tracking, measuring the position of ...

, and

environmental monitoring Environmental monitoring is the processes and activities that are done to characterize and describe the state of the environment. It is used in the preparation of environmental impact assessments, and in many circumstances in which human activit ...

. Of particular use in surveillance applications is the ability to perform a dense 3D reconstruction of a scene and storing data over a period of time, so that operators can view events as they unfold over any period of time (including the current moment) from any arbitrary viewpoint in the covered area, even allowing them to "fly" around the scene in real time. High-level analysis using

object recognition Object recognition – technology in the field of computer vision for finding and identifying objects in an image or video sequence. Humans recognize a multitude of objects in images with little effort, despite the fact that the image of the ...

and other techniques can intelligently track objects (such as people or cars) through a scene, and even determine what they are doing so that certain activities could be automatically brought to the operator's attention. Another possibility is the use of visual sensor networks in telecommunications, where the network would automatically select the "best" view (perhaps even an arbitrarily generated one) of a live event.

References

^ Cheng Qian, Hairong Qi
Coverage Estimation in the Presence of Occlusions for Visual Sensor Networks
DCOSS 2008: 346–356 #

^ Soro S., Heinzelman W.
''A Survey of Visual Sensor Networks''
Advances in Multimedia, vol. 2009, Article ID 640386, 21 pages, 2009. #

^ Yang Bai, Hairong Qi
Feature-Based Image Comparison for Semantic Neighbor Selection in Resource-Constrained Visual Sensor Networks
EURASIP Journal on Image and Video Processing, Volume 2010 (2010). {{refend

External links

CMUcam3
Applications of computer vision Wireless sensor network

Applications

See also

References

External links