Accuracy evaluation of an on-line kinematic system via dynamic tests

The study presents an experimental methodology for evaluating the accuracy and reliability of the kinematic data collection of an on-line optoelectronic system used in biomechanics studies. The methodology is based on a series of dynamic tests using an independently measured and controlled frequency input varying systematically five different factors--(1) camera-object distance, (2) distance from calibrated field, (3) size of the calibration field, (4) position in the calibration field and (5) rotation speed. The proposed methodology is addressed mainly towards medical related research or biomechanical analysis of human joints where a high degree of accuracy is of prime importance. It is used to evaluate the ELITE motion analysis system. The results of the study showed that the error distribution is sensitive to relatively small changes of the first four factors as the error magnitude was not affected strongly remaining within 2% of the object length for the majority of the experiments.