In the Pool: Vision System Analyzes Swimmers’ Performance at World Championship
The FINA 2013 World Swimming Championships held in Barcelona, Spain in July 2013 were the stage for the world’s elite of swim sports. Yet it also featured a technological innovation with InThePool 2.0, an image-processing system that captured and analyzed images of the swimmers down to every single stroke. The collected data were distributed to swimmers and their coaches for analysis purposes and also to worldwide media for their broadcast reporting.
The system was designed by STT Systems, a Spanish imaging specialist from San Sebastian, in co-operation with Barcelona’s high-performance sports training center CAR (Centre d’Alt Rendiment) and the Spanish imaging specialist and distributor for AVT cameras INFAIMON.
12 AVT Mako cameras monitor 8 lanes
InThePool 2.0 relies on a network of 12 Mako digital cameras from Allied Vision Technologies suspended above the swimming pool. The cameras are arranged as two rows of six monitoring four lanes each. Each camera has a field of view of approximately 13x13m. Overlays between neighboring cameras allow for a seamless coverage of eight 50m swimming lanes.
In this system, the cameras capture images at up to 50 fps. They are connected to the host computer via a GigE Vision compliant Gigabit Ethernet interface. The collected images are synchronized with the World Championship’s official timing from Omega and analyzed in near-real time. Statistical reports are automatically generated as soon as the race is over.
The data produced include the speed at specific milestones including start, turns and finish, as well as stroke length and stroke frequency (number of strokes per meter) for each individual swimmer. The system uses pattern recognition to identify strokes for any of the four main swimming styles by analyzing the position of the arms of the swimmers.
The reports are generated in XML format. Thanks to this data, coaches and media reporters can precisely analyze the race and the performance of individual swimmers – for example identify if time was lost at the start, during turns or at the end of the race.
First real-life implementation of Mako cameras with worldwide audience
The FINA World Swimming Championship was the first real-life application of Allied Vision Technologies’ Mako camera series. The Mako is a small and affordable entry-level camera which was introduced in the market in the fall of 2013. Thanks to the close partnership between Allied Vision Technologies and its local distribution partner INFAIMON, pre-series models of the Mako could be used at the Championships in Barcelona even before the actual market introduction of the camera.
The model used was the Mako G-125C, which features a 1.2 Megapixel CCD-sensor from Sony (ICX445) in its color version. The Mako delivers up to 30 frames per second (fps) at full resolution over a GigE Vision compliant Gigabit Ethernet interface. Thanks to their highly precise sensor alignment, they produce razor-sharp images for an accurate recognition of the arm movement of the swimmers, which is used to calculate the stroke frequency.
“One major challenge of the application was the long distances between the cameras and the host-computer”, explains Pablo Callejo, Vice President of sales of STT Systems. “Palau San Jordi is 4,500 sqm large and 45m high and the swimming pool alone 25x50m, so we had to bridge very long distances between the cameras suspended high above the pool and the host”. With the GigE Vision compliant Gigabit Ethernet interface of the Mako cameras, up to 100m can be covered with just one interface cable. Longer distances were bridged using Ethernet switches.
After thorough tests at the CAR premises in Barcelona, InThePool was implemented successfully during the two weeks of the FINA World Championships (July 19 – August 4, 2013). “Although the Mako cameras were not series products, they worked perfectly reliably and delivered high quality images with high frame rates”, says Pablo Callejo.
Since the end of the competition, the system is now installed back at the CAR to help the next generation of high-performance swimmers and their coaches analyze and improve their technique.