Information about a piece of news titled New method for analyzing injury videos
New method for analyzing injury videos
Intoduction
A new method for reconstructing human 3D motion from video sequences was published in the April edition of Journal of Biomechanics. This technique has been developed at the Oslo Sports Trauma Research Center over the last years, and is particularly well suited for analyses of sports injuries.
In 2001, the Oslo Sports Trauma Research Center initiated the development of a novel technique for 3D motion reconstruction from ordinary video tapes, since this was considered necessary for improved understanding of the mechanisms of injury in e.g. basketball and team handball ACL injuries.
The method is based upon the idea that a computer-generated model can be configured/animated to imitate the movements of the video-recorded athlete. The commercially available software Poser is used as environment for the matchings.
The model-based image-matching technique was developed with the intension to be used in a variety of different situations, whether it was a single camera recording, or if multiple cameras were available. Also moving cameras (including panning, zooming) can be handled using this technique.
To validate the method, we conducted a laboratory trialwith one test subject performing jogging and side step cutting, while being filmed with three ordinary video cameras. This provided three single camera matchings, three double camera matchings and one triple camera matching for each of the motions. The test subject wore 33 reflective skin markers and was filmed with a seven-camera, 240 Hz motion analysis system.
The root mean square (RMS) hip and knee flexion/extension angle differences were less than 12° for all the matchings. Estimates for ad-/abduction (<15°) and internal/external rotation (<16°) were less precise. RMS velocity differences up to 0.62 m/s were found for the single camera matchings, but for the triple camera matching the RMS differences were less than 0.13 m/s for each direction. In conclusion, the method was found adequate for analyzing situations where it is not possible to conduct controlled experiments, e.g. sports injury situations.
The primary investigator for this study was Tron Krosshaug MSc, in cooperation with professor Roald Bahr MD PhD.
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