%0 Journal Article
%T A New Calibration Methodology for Thorax and Upper Limbs Motion Capture in Children Using Magneto and Inertial Sensors
%A Luca Ricci
%A Domenico Formica
%A Laura Sparaci
%A Francesca Romana Lasorsa
%A Fabrizio Taffoni
%A Eleonora Tamilia
%A Eugenio Guglielmelli
%J Sensors
%D 2014
%I MDPI AG
%R 10.3390/s140101057
%X Recent advances in wearable sensor technologies for motion capture have produced devices, mainly based on magneto and inertial measurement units (M-IMU), that are now suitable for out-of-the-lab use with children. In fact, the reduced size, weight and the wireless connectivity meet the requirement of minimum obtrusivity and give scientists the possibility to analyze children¡¯s motion in daily life contexts. Typical use of magneto and inertial measurement units (M-IMU) motion capture systems is based on attaching a sensing unit to each body segment of interest. The correct use of this setup requires a specific calibration methodology that allows mapping measurements from the sensors¡¯ frames of reference into useful kinematic information in the human limbs¡¯ frames of reference. The present work addresses this specific issue, presenting a calibration protocol to capture the kinematics of the upper limbs and thorax in typically developing (TD) children. The proposed method allows the construction, on each body segment, of a meaningful system of coordinates that are representative of real physiological motions and that are referred to as functional frames (FFs). We will also present a novel cost function for the Levenberg¨CMarquardt algorithm, to retrieve the rotation matrices between each sensor frame (SF) and the corresponding FF. Reported results on a group of 40 children suggest that the method is repeatable and reliable, opening the way to the extensive use of this technology for out-of-the-lab motion capture in children.
%K magneto and inertial measurement unit
%K anatomical coordinate system
%K functional frame definition
%K calibration protocol
%K children motion capturing
%U http://www.mdpi.com/1424-8220/14/1/1057