ASHCOM Video Smoke Detection

All fire safety professionals constantly seek the benefits of early warning of potential fires. In the perfect World they imagine being able to place hundreds of smoke detectors millimetres above and around the items or areas at risk. This would certainly enable a fast response to a potential fire, saving valuable time even in voluminous areas or where a high airflow may be present. But of course such a dream is not possible from a practical or financial point of view, OR IS IT?

Principle of Operation:

VSD is based on sophisticated computer analysis of the video image seen by the CCTV camera (sensor). Using advanced image-processing technology and extensive detection (and known false alarm phenomena) algorithms; the VSD can automatically identify the distinct characteristics of smoke patterns. The fire detection industry has an abundance of known smoke signatures and all of these are built into the system to give an accurate decision on whether smoke is present. The VSD is so accurate in it's analysis that it can even differentiate between steam and smoke.

The VSD system uses standard CCTV equipment linked to a self contained processing system which is capable of recognising small amounts of smoke within the video image and alerting the system operator both at the processor and by a variety of remote outputs.

The VSD system employs highly complex algorithms to process video information from up to eight cameras simultaneously. Under normal conditions with all eight cameras connected the system achieves a 5Hz-frame rate for each channel.

The video hardware is designed to allow simultaneous real time digitising of all eight images, which means that the system does not multiplex images and, therefore, no information is lost or delayed. All alarm condition images are logged, time & date stamped, and stored within the system's memory.

The VSD system detects smoke rapidly by looking for small areas of change within the image at the digitisation stage and only passing these pixel changes to the main processor for further filtering. The video information is passed through a series of filters, which seek particular characteristics that can be associated with smoke behaviour. Further analysis is then carried out on the relationships between the filtered characteristics to determine whether all the conditions have been met for the system to confidently predict the presence of smoke.

The system installer has the ability to vary the amount of smoke signal, and the length of time that the smoke exists before an alarm condition is raised to cater for situations where there may be background smoke present. The installer may also divide the video image into zones and programme the system to alarm only if smoke is present in 2 or more zones.

Applications:

The VSD system is now in operation in a variety of applications throughout the world, either installed as a working system or on trial. Typical applications that can benefit from a VSD smoke detection system include:-