Check out the lifesaving technology featured in this story from the UK:
The system was fitted to the Bangor pool in March 2003 at a cost of £65,000 and involves eight overhead and four underwater cameras.
The Poseidon technology can detect movement, trajectory and texture of underwater objects. It then compares images to a database of thousands of examples of swimmers in trouble.
If it finds a match, it alerts lifeguards using a pager message which also displays a diagram showing the location of the stricken swimmer.
The story details the rescue of a ten-year-old girl in North Wales.
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