A digital camera system is provided to measure a moving sportsman, for example to determine peak altitude, spin ratio and airtime. A wireless triangulation system is provided to track a moving sportsman to determine metrics such as peak altitude, rotation, drop distance and airtime. A stride-rate system...http://www.google.com.tw/patents/US6813586?utm_source=gb-gplus-share專利 US6813586 - Event and sport performance methods and systems
