Timothy R Coles, PhD, Caroline G Cao, PhD, Cedric Dumas, PhD. Commonwealth of Scientific and Industrial Research Organisation, Wright State University.
Ergonomic assessment for surgeons and evidence based medical simulation are increasingly recognized as enablers for more productive and safer clinical operations. These can be performed by gathering in-depth information about practitioner’s interactions within their working environment. However observation techniques that can be performed by non specialists are crude, requiring pen and paper notation. The ideal solution, advanced motion tracking platforms such as those used in the film industry, can only be afforded by large institutions, require an expert to run and require the practitioner to be covered in precisely placed reflective markers or electronic sensors, which can interfere or prove hazardous with the aseptic environment. We present here the ETrack, a motion tracking solution that requires no markers, uses low cost hardware, is simple to set up and compact to transport.
Methods and Procedures
The ETrack (www.aehrc.com/eTrack) posture capture tool uses Microsoft’s Kinect Infra Red tracking hardware for posture capture. This technology was designed primarily for computer games and is a low cost (RRP $249 USD) markerless tracking solution.
ETrack (Figure 1), a Microsoft Widows 7 program enables the researcher to visualize the surgeon being tracked, in real-time, as an animated two-dimensional distance map. Prior to recording posture data, the researcher can select points of interest on the tracked skeleton to be recorded. During recording, the xml data file is populated with position data and a time stamp at a rate of 30 times per second. The software tool provides pre-programmed flag buttons and a free text option to highlight or note positions of interest in real-time for post analysis. In addition to real time posture and position capture, retrospective analysis of scenes captured using the Kinect Studio recording platform (a free Microsoft tool) can be performed.
Results and Conclusions
ETrack has been successfully used in a published bronchoscopy posture analysis study. The software is free and a simple interface makes the tool simple to use for those without advanced computer programming skills. The exchangeable xml data format can be simply loaded into most analysis software. An xml loading package for R is provided.
Figure 1: ETrack. Posture and position capture software. (top left) Visualisation of captured depth map. (top middle) A 3D skeletal view of a practitioner’s movements. Shown visualising upper limbs only. (top right) A camera view of the practitioners interactions. (bottom right) A 2D distance view of the practitioners head (white) right hand (green) and left hand (red) from the motion sensor (top black bar). (bottom centre) A set of buttons to flag particular poses during a procedure. (bottom left) Users can select points of the tracked skeleton they wish to record.