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Critical Reviews™ in Physical and Rehabilitation Medicine

ISSN Print: 0896-2960
ISSN Online: 2162-6553

Critical Reviews™ in Physical and Rehabilitation Medicine

DOI: 10.1615/CritRevPhysRehabilMed.v22.i1-4.40
pages 49-59

Static and Dynamic Calibration of an Eight-Camera Optical System for Human Motion Analysis

Jeffrey D. Kertis
Orthopaedic and Rehabilitation Engineering Center (OREC) ; Medical College of Wisconsin, Marquette University
Jessica M. Fritz
Orthopaedic & Rehabilitation Engineering Center (OREC), Marquette University/The Medical College of Wisconsin, Milwaukee, Wisconsin; Department of Orthopaedic Surgery, Medical College of Wisconsin, Milwaukee, Wisconsin
Jason T. Long
Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
Gerald F. Harris
Department of Orthopaedic Surgery, Medical College of Wisconsin, Milwaukee, Wisconsin; Orthopaedic and Rehabilitation Engineering Center, Marquette University/Medical College of Wisconsin, Milwaukee, Wisconsin
Director of Orthopaedic Research, Medical College of Wisconsin

ABSTRACT

An eight-camera Optitrack motion capture system was evaluated by performing static, linear dynamic, and angular dynamic calibrations using marker distances associated with upper and lower extremity gait and wheelchair models. Data were analyzed to determine accuracy and resolution within a defined capture volume using a standard Cartesian reference system. Static accuracy ranged from 99.31 to 99.90%. Static resolution ranged from 0.04 ± 0.15 to 0.63 ± 0.15 mm at the 0.05 level of significance. The dynamic accuracy ranged from 94.82 to 99.77%, and dynamic resolution ranged from 0.09 ± 0.26 to 0.61 ± 0.31 mm at the 0.05 level of significance. These values are comparable to those reported for a standard Vicon 524 (Oxford Metrics, Oxford, England) motion analysis system. The results support application of the lower cost Optitrack system for 3D kinematic assessment of upper and lower extremity motion during gait, assisted ambulation, and wheelchair mobility.