Abstract

DIAZ NOVO, Carlos et al. The impact of technical parameters such as video sensor technology, system configuration, marker size and speed on the accuracy of motion analysis systems. Ingenier. mecáni. tecnolog. desarroll [online]. 2014, vol.5, n.1, pp.265-271. ISSN 1665-7381.

In biomechanical assessments, minimizing errors and achieving accurate representations of human movements are the main goals of motion capture systems. Although 3D camera-based motion capturing systems are effective for accurate acquisition of motion, their performance is highly dependent on various parameters. This paper examines the how variations in independent technical parameters such as video camera sensor technology, system configuration, marker size and speed influence the accuracy of the kinematic measurements. A method was developed to systematically assess accuracy and precision of motion capture systems by measuring the mean absolute inter-marker distance errors and standard deviations respectively. A custom-made dynamic measurement protocol was used to test the performance of three motion capture systems; two different Vicon motion capture systems and a low-cost motion capture system implemented in the Santiago de Cuba Hospital (SCH) using common video cameras. For the two Vicon labs, the individual effects and interactions between the parameters and the spatial measurements of the motion analysis systems were able to be determined. However, the Santiago lab was unable to accurately track small changes in the elements of the measurement system and therefore was not recommended for small human movements. Although the Santiago lab reported to be significantly less accurate than the two other labs, results showed that the mean absolute inter-marker distance error was minimized in the center of the capture volume. This information is essential in the implementation of this system as a clinical assessment tool and is a factor that should be considered for low accuracy systems.

Keywords : precision; video; capturing systems; human movement; biomechanics; measurements accuracy; video camera; inter-marker distance.

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