Accuracy assessment of an N-ocular motion capture system for surgical tool tip tracking using pivot calibration

Optical tracking system (OTS) is nowadays the most commonly used surgical instrument tracking system for image-guided surgery (IGS) because of its high accuracy and robustness. However, it suffers from occlusion problem during the surgery. Multi-camera tracking system can potentially eliminate this problem with its redundancy of camera numbers. However, no systematic evaluation has been conducted to study the feasibility of a multi-camera tracking system in surgical instrument tracking. In this paper, the pivot calibration and tip tracking accuracy using customized phantom were respectively evaluated at three seperate locations. Various evaluation metrics were included to assess the pivot calibration and tracking accuracy comprehensively. The results indicate that pivot calibration process should be conducted near central place of field of view (FOV) in order to achieve less calibration error. The target registration error (rms) of the surgical instrument tool tip tracking was 0.39, 0.35 and 0.75 mm when the phantom was placed at three seperate locations in the FOV of tracking system. The experimental results show the multi-camera tracking system's potential possibility to be used in image-guided surgery.