title: Anatomical Calibration through Post-Processing of Standard Motion Tests Data.
abstract: The inertial measurement unit is popularly used as a wearable and flexible tool for human motion tracking. Sensor-to-body alignment, or anatomical calibration (AC), is fundamental to improve accuracy and reliability. Current AC methods either require extra movements or are limited to specific joints. In this research, the authors propose a novel method to achieve AC from standard motion tests (such as walking, or sit-to-stand), and compare the results with the AC obtained from specially designed movements. The proposed method uses the limited acceleration range on medial-lateral direction, and applies principal component analysis to estimate the sagittal plane, while the vertical direction is estimated from acceleration during quiet stance. The results show a good correlation between the two sets of IMUs placed on frontal/back and lateral sides of head, trunk and lower limbs. Moreover, repeatability and convergence were verified. The AC obtained from sit-to-stand and walking achieved similar results as the movements specifically designed for upper and lower body AC, respectively, except for the feet. Therefore, the experiments without AC performed can be recovered through post-processing on the walking and sit-to-stand data. Moreover, extra movements for AC can be avoided during the experiment and instead achieved through the proposed method.
authors.affiliation: Graduate School of Advanced Science and Engineering, Waseda University, Tokyo 169-8555, Japan. kong.ws@fuji.waseda.jp.
authors.forename: Weisheng
authors.initials: W
authors.lastname: Kong
authors.affiliation: Graduate School of Creative Science and Engineering, Waseda University, Tokyo 169-8555, Japan. s.sessa@aoni.waseda.jp.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Sessa
authors.affiliation: Wolfson School of Mechanical, Electrical and Manufacturing Engineering, Loughborough University, Loughborough LE11 3TU, UK. m.zecca@lboro.ac.uk.|National Centre for Sport and Exercise Medicine, Loughborough LE11 3TU, UK. m.zecca@lboro.ac.uk.|NIHR Leicester-Loughborough Diet, Lifestyle and Physical Activity Biomedical Research Unit, Loughborough LE11 3TU, UK. m.zecca@lboro.ac.uk.
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Zecca
authors.affiliation: Department of Modern Mechanical Engineering, Waseda University, Tokyo 169-8555, Japan. contact@takanishi.mech.waseda.ac.jp.|Humanoid Robotics Institute (HRI), Waseda University, Tokyo 162-0044, Japan. contact@takanishi.mech.waseda.ac.jp.
authors.forename: Atsuo
authors.initials: A
authors.lastname: Takanishi
mesh_terms: D061725:Accelerometry; D001696:Biomechanical Phenomena; D015374:Biosensing Techniques / Q000379:methods*; D002138:Calibration; D006801:Humans; D009038:Motion; D009068:Movement / Q000502:physiology; D011187:Posture / Q000502:physiology; D025341:Principal Component Analysis; D060726:Torso / Q000502:physiology; D016138:Walking / Q000502:physiology
keywords: accelerometer; anatomical calibration; functional calibration; inertial measurement unit; motion test; principal component analysis; sagittal plane; sensor-to-body alignment; sit-to-stand; walking