One of the largest ski jumps in the world, the so-called "Rennsteig Ski Jump" in Oberhof, Thuringia, is used as an Olympic base by numerous national teams from all over the world for training.
Bei Geschwindigkeiten von mehr als 90 km/h während eines Sprungs waren die Anforderungen an ein Videoanalysesystem hoch. Diese konnten wir mit unserem Multikamerasystem utilius kiwano erfüllen, das seit 2015 auf der Skisprungschanze in Oberhof im Einsatz ist.
Starting point and objective:
In coordination with the OSP Thuringia, the city of Oberhof, the Institute for Applied Training Science as well as the coaches, clear requirements for a video analysis system emerged in 2015.
The specifications for the cameras were as follows: They were to display the athlete in the image over a large area at all times, automatically recognize him and record him synchronously - and from different perspectives.
In addition to this, further requirements were placed on the multi-camera system on the ski jump:
- On the one hand, cameras should be weatherproof and enable FullHD recording.
- On the other hand, it was important to develop user-friendly software that could be operated by anyone.
- Last but not least, the automatic as well as markerless tracking of the athletes with the help of the cameras was an important topic.
Since ski jumping can involve temperatures as low as -20 degrees, protecting the cameras was a high priority: they were installed in outdoor housings that offer good protection from the elements.
Implementation:
At the beginning of the project, the requirements were defined with all project partners involved.
The project team now created the requirements profile - the basis for the project sketch. This sketch describes the utilius kiwano multicamera system and presents its basic components (see structural sketch).
A total of 12 cameras have now been installed to record the athlete from the ski jump down to the valley:
- A PTZ camera positioned behind the athlete zooms in on him as he jumps.
- Two face cameras ensure that the athlete is easily recognizable.
- Finally, nine more cameras were attached, all recording the athlete from the side.
To be able to record the athletes automatically, we also integrated the existing light barrier system. With the help of a specially developed system, the cameras now start recording automatically with the light signal. The system thus functions autonomously: In detail, this means that coaches and sports scientists automatically receive recordings without having to press any buttons.
Following the video recording, all camera images are stored on a server and processed further. If an athlete can now be seen in certain sequences, these images are cut out and then merged into a video in the further process.
The challenges:
Tracking the athletes automatically from behind proved to be particularly difficult. Due to the different approach speeds of the athletes, it was difficult to determine the perfect setting for the PTZ camera. With the help of many training jumps, this challenge was overcome.
In addition, disturbances such as background movements or poor visibility due to snowflakes occur time and again during ski jumping. The system was therefore designed to filter out almost any interference.
Results:
The system can meet all requirements and is ready for use at any time.
With utilius kiwano, the OSP Oberhof has obtained software that is user-friendly and can be operated by anyone. Once a jump has been made, the athlete can almost immediately - from two different perspectives - analyze his jump. This is possible in the warm-up room with the help of a monitor.
Analyses and evaluations can also be carried out without any problems with the aid of a montage specially adapted to ski jumping. In addition, there is a measurement module that can easily determine body angles, for example.
The system is so flexible that it can be expanded with additional cameras or display monitors at any time.
The ski jump in Oberhof is thus equipped with the latest technology thanks to the multi-camera system and will thus continue to offer top athletes as well as junior athletes the optimum conditions for practicing skiing in the future.
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