Computer Vision News - July 2016

minutes the danger of death becomes very real. This means that after the person has been identified as a motionless volume on the bottom of the pool, we have only 15 seconds to trigger an alarm. This deadline takes into account the 10 seconds it takes the drowned person to reach the bottom and the time it will take to the lifeguard to learn the exact location of the event, reach the optimal diving point, dive and rescue the victim. The whole process is designed to take slightly less than one minute. Of course, increasing this 15 seconds limit would diminish the false positives (i.e. the false alerts) , but in that case our application would cease to be a security system. We asked Bœglin to tell us more about the imaging used by the system: one camera is dedicated to the air-water interface, the other one is in charge of analyzing the trajectory of the volumes. It is key to give key information to safety personnel: the position of the victim in the pool, measured with precise metric coordinates; and the time lapsed since the beginning of the alert, which is both visual and acoustic. The app does not use mobile phones, since that might turn the regular attention of lifeguards from the basin to their devices. The image on the right is taken from the video of a real alert in a UK swimming pool in 2015 (full video is here ) . This is one of the 33 drowning cases successfully detected by Poseidon to date. Though a 100% safety is not possible, no casualty has ever been detected in any of the 250 pools equipped by Poseidon in 15 countries . These drownings were in many cases undetected by lifeguards, whose majority has never experienced a severe accident. The main obstacles to a wider dissemination of this solution are legal: it is difficult to equip pools in countries where management has no obligation nor responsibility: in Germany everyone swims at his/her own risk and nobody else is accountable for accidents. Security has a cost, which will be paid only by communities which are sensitive to this subject. That is quite the case in Scandinavia, where a technology which increases safety becomes a must have solution. It is also easier to invest money to increase safety at the moment of building a swimming pool. On the other hand, an already established public pool generally loses money and it will be difficult to find the budget to make it safer, until a fatal accident happens, paving the way for investments in safety solutions. Computer Vision News Application 15 “ You cannot let more than one minute pass between the immersion of the airways and the rescue by a lifeguard ” Application