A Quality Control Check to Ensure Comparability of Stereophotogrammetric Data between Sessions and Systems.

Kirsty Scott,Claudia Mazzà,Ellen Buckley,Lisa Alcock,Lars Schwickert,Eran Gazit,On Behalf Of The Mobilise-D Consortium ,Andrea Cereatti,Tecla Bonci,Clint Hansen

doi:10.3390/s21248223

Abstract

Optoelectronic stereophotogrammetric (SP) systems are widely used in human movement research for clinical diagnostics, interventional applications, and as a reference system for validating alternative technologies. Regardless of the application, SP systems exhibit different random and systematic errors depending on camera specifications, system setup and laboratory environment, which hinders comparing SP data between sessions and across different systems. While many methods have been proposed to quantify and report the errors of SP systems, they are rarely utilized due to their complexity and need for additional equipment. In response, an easy-to-use quality control (QC) check has been designed that can be completed immediately prior to a data collection. This QC check requires minimal training for the operator and no additional equipment. In addition, a custom graphical user interface ensures automatic processing of the errors in an easy-to-read format for immediate interpretation. On initial deployment in a multicentric study, the check (i) proved to be feasible to perform in a short timeframe with minimal burden to the operator, and (ii) quantified the level of random and systematic errors between sessions and systems, ensuring comparability of data in a variety of protocol setups, including repeated measures, longitudinal studies and multicentric studies.

Highlights

This study clearly demonstrated the need for assessing systematic errors under dynamic conditions, the proposed setup requires a separate trial for each position of the plate and subsequently would involve additional time prior to each data collection, which may not always be available in clinicalbased laboratories
Based on the encouraging results from Di Marco et al [21], this study aims to develop and validate a simple and time effective quality control (QC) check to estimate the random and systematic errors of different SP systems that can be adopted in the routine running of SP data collections, with minimal burden to the operator, no need for additional equipment and automated reporting of random and systematic errors
CO1 was calibration object chosen for this study was the Vicon calibration wand (Vicon Motion used for all data collection except the assessment of the QC check’s reliability with a Systems, Oxford, UK) (Figure 1), which will be referred to as CO1 throughout

Summary

Introduction

Optoelectronic stereophotogrammetric (SP) systems are integral in the field of human movement research for quantifying the kinematic variables of human movement through the instantaneous 3D tracking of retroreflective or light emitting markers [1]. These systems have gained recognition in clinical application and diagnostics [2,3,4] and are regarded as the gold standard for the validation of other technologies with a similar purpose [5,6,7,8]. Rigorous testing to attain a metrological characterisation and comprehensive understanding of the consistency in error between sessions and across systems is crucial for protocol designs such as, repeated measures, longitudinal studies and multicentric studies

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Conclusion