Quantitative Study on Error Sensitivity in Ultrasound Probe Calibration with Hybrid Tracking

Three-dimensional (3D) freehand ultrasound (US) imaging enabled by the external tracking system requires an accurate calibration process to transform the tracked motion information from the markers to the US frames. The previously proposed phantomless calibration method can be further improved using both optical tracking and image-based tracking. This study provides a quantitative analysis on the error sensitivity before implementing the image-based tracking during the calibration process. A linear relationship was found between the perturbation in imaging plane motion estimation and the error caused in the calibration solution. The error to perturbation ratio was within 0.5 in most cases and can reach up to around 0.9 in some poor cases. The overall analysis showed a good error tolerance for the hybrid tracking enabled US probe calibration.