The Role of Depth for Human Motion Assessment with a Single RGB-D Camera: Preliminary Findings

Telerehabilitation is an emerging remote therapy method, particularly for people with neurological disorders. In this context, single-camera markerless motion capture technology offers a cost-effective, accessible and easy-to-use solution for motion assessment. Differently from multi-camera systems or those requiring physical markers, single-camera approaches are suitable for home environments, which makes them ideal for telerehabilitation. However, most studies have focused on movements parallel to the camera’s plane, leaving a gap in understanding their accuracy and precision for more complex, multi-directional movements. This study aims to fill this gap by analyzing hip movements in different directions of ten unimpaired participants using a single RGB-D camera. Comparing markerless approaches with a marker-based system, we found that single-camera methods perform well in the frontal plane, while the error increases in movements involving a sagittal component. This study highlights the strengths and limitations of camera-based motion analysis, contributing to the advancement of telerehabilitation.