Poseidon drowning detection system

The Poseidon drowning detection system is a computer aided drowning detection system. The system is commonly installed in bathing areas, such as municipal swimming baths, waterparks, therepeutic baths, and other places where there is standing water in which there is a risk of drowning.

Principle of operation
The system consists of overhead and underwater cameras that are connected to a computer vision system that uses multiple overlapping views (epipolar geometry, fundamental matrix, essential matrix, etc.) to detect motionless bathers below the surface of the water in the baths.

Installed sites
While the company maintains a list of installed sites, the list tends to be incomplete and out of date. The most up to date list on the company website is the French version of their web page whereas the USA version is greatly out of date. Additionally, there are many baths that have the system installed, but are not listed on the site. None of the outdoor pool installations are listed on the company website; these are still of an experimental nature. Also installations in baths that are not used for swimming are not yet fully listed, since this is also an experimental usage. For example, use in therepeutic, soaking, and whirlpool baths is still being worked out in many of the installed sites, because of the more complex nature of the situation (greater variation in activity of the persons in the bath, in contrast to simple lane-swim where everyone is going in the same direction, etc.).

Sites removed
The company website used to list various pools that are no longer listed on the site. The websites for these removed pools still exist on the company website, but are not linked to by the list of installed sites page. Examples include: In other words, there used to be seven sites listed for the UK, but now there are only five, since the above two have been removed from the list. Contacting the pool owners, it has appeared that they still have the system installed and in use, so it is not clear why the company has removed them from the list of installed sites.
 * Guidford
 * Wycombe

Success and failure
The selection of listed sites seems somewhat random, i.e. the selection process appears to not merely be a selection of sites where the system works best. For example, although the Miramar (Florida, US) pool (where the system has failed to work well) is not listed, Blackshots Leisure Centre (where the system had very positive review) is also not listed.


 * Anti-drowning system not 100% (Sun-Sentinel)
 * MIRAMAR The manufacturer has been trying for almost two years, but a system of cameras designed to detect drowning swimmers still needs more work. In April 2003, the city agreed to be a test site for  Poseidon Inc., which has created a system linked to a computer that detects "non-motion."
 * South Florida Sun - Sentinel - Fort Lauderdale, Fla. Author: Nick Sortal Staff Writer, Jan 26, 2005

This article refers to the Miramar Aquatic Complex on 6920 SW 35th St.

Blackshots Leisure Centre is the site where the installation was part of a recent study that found that drowning detection systems make sense, even if you only consider economic factors (i.e. in the context of deciding how many lifeguards to have on staff).

Overall, the system has worked very well in some locations, and not so well in other locations, and there are a number of factors that seem to determine how well the system works. For example, it seems to work in some lane-swim type pools where the usage is structured, but it doesn't work well in wave pools, where the usage is very chaotic. Despite this, many lifeguards in lane-swim type pools have observed difficulties, including at some of the pools listed on the Poseidon website. It seems that despite claims otherwise, Poseidon is often easily fooled by objects such as kickboards, hula-hoops, and even glares on the water and lane markings at the bottom of the pool, while it consistently misses professional lifeguard instructors who are playing excellent passively drowning victims for extended periods of time.

Competing companies
Other companies, such as Swimguard, and Drowning Early Warning System (DEWS) also provide similar technology.

Swimguard prefer the term Drowning Prevention System as detection implies that it has already happened. Swimguard's system is often used in wave pools and beach-resort style pools where the Poseidon system doesn't work as well. However, the Poseidon system is also capable of hybrid usages, i.e. automated drowning detection in some areas and merely facilitating human monitoring in other areas where the computer algorithms don't work as well. In this sense the Poseidon system capabilities are a proper superset of the Swimguard system capabilities.

DEWS focus on detection of distress signal in the early stage to facilitate timely rescue.

Risks
Many lifeguards will actually leave their station and the pool entirely unguarded to shut off the Poseidon alarm; however, it seems that these guards rarely check to see if the alert was, in fact, correct; instead, many guards simply ignore the alert and take their eyes off the pool for a few moments to press the "cancel" button a few times until the alarm stops beeping.

Inexperienced lifeguards often become lulled into a false sense of security that Poseidon will catch any potential victims and sound an alert. This is evidenced in that lifeguards at some Poseidon facilities have been observed staring blankly the pool, the wall, or the ceiling, or talking with other guards and walking away from the pool they are supposed to be guarding.