The Poseidon system gives the lifeguard underwater “eyes.” It’s made up of overhead and/or 
underwater cameras, a central computer, an LED display panel and a waterproof touch-screen. The cameras’ analog video feeds are converted to a digital signal by a device called a frame grabber – made by Montreal-based Matrox Imaging – so they can be analyzed by Poseidon’s software.
Developed in France and first sold in 2000 by MG International-Poséidon, Poseidon is an anti-drowning detection system that analyzes video streams in real time and alerts lifeguards to people in trouble in the pool.
The Canadian Red Cross says recreational swimming is the second-leading activity that leads to drowning in Canada. Most drowning victims are young males and those who swim alone.
Drowning can be silent and quick. A swimmer in trouble can enter what lifeguards call a “drowning spiral” within seconds. Once caught in that spiral, the victim becomes immobile, cannot call out and loses consciousness in as little as 12 seconds.
When lifeguards are able to intervene and begin resuscitation within 30 seconds, the victim stands a good chance of recovery. As the amount of time involved in a rescue goes up, the chances of a successful resuscitation fall.
The software algorithms analyze a floating object’s volume and texture to determine if it is a person or just an object in the pool. Once an individual is identified, Poseidon searches for unusual behaviour by comparing the swimmer’s position over consecutive images. When the software detects a motionless presence at the bottom of the pool for 10 seconds, an alarm and siren are activated.
The monitors immediately show the location of the victim, allowing the lifeguards to bring him or her out of the water quickly and start resuscitation.
Read more: http://www.cbc.ca/technology/story/2010/07/22/f-pool-safety-technology-drowning.html#ixzz0uRwh83qP
Ten seconds seems like a long time to me. I suppose it doesnt take long for them to respond and get the victim out of the water. But still if someone is perfectly still i dont see the need for them to sink before the life guard is alerted!
Ten seconds seems like a long time to me. I suppose it doesnt take long for them to respond and get the victim out of the water. But still if someone is perfectly still i dont see the need for them to sink before the life guard is alerted!