Effects of the calibration procedure on the metrological performances of stereophotogrammetric systems for human movement analysis

Roberto Di Marco,Fabrizio Patanè,Claudia Mazzà,Stefano Rossi,Enrico Castelli,Paolo Cappa

doi:10.1016/j.measurement.2016.01.008

Abstract

This paper proposes a methodology for evaluating the effect of different stereophotogrammetric system calibration procedures on the calculation of marker-based kinematics information. The methodology, based on calibrating the system using data recorded from capture volumes of different sizes and in trials of different durations, was applied to two different systems. The calibration data were used to reconstruct the static and dynamic position and orientation in space of a rigid wand carrying markers in known positions. The inaccuracies in the reconstruction of distances and angles from the wand markers were independent on the calibration data, with average errors lower than 1.7 mm and 0.7°, respectively. Similar results were obtained from human gait data, with the highest variations observed in the transverse plane kinematics and in the foot segment, suggesting that successful calibration procedures of different durations and performed in different volumes did not affect the metrological performance of the investigated systems.

Highlights

IntroductionMovement analysis techniques have been increasingly used to study human/animal motion [1,2,3,4]
In the past decades, movement analysis techniques have been increasingly used to study human/animal motion [1,2,3,4]
Similar results were obtained from human gait data, with the highest variations observed in the transverse plane kinematics and in the foot segment, suggesting that successful calibration procedures of different durations and performed in different volumes did not affect the metrological performance of the investigated systems

Summary

Introduction

Movement analysis techniques have been increasingly used to study human/animal motion [1,2,3,4]. Besides emerging techniques based on MIMU systems [5,6,7,8] and markerless approaches [9,10,11,12], the majority of the human movement analysis techniques are based on the measurement of three-dimensional posi-. Tion of active or passive markers attached to the body skin, as obtained using a stereophotogrammetric approach. These markers are used to track the three-dimensional pose of the subject’s bones, to which they are uniquely associated through a procedure called anatomical calibration [1].

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Conclusion