Correcting Electromagnetic Tracker's Position Error Using Orientation Information Based on Hardy's Multi-Quadric Method

Electromagnetic tracking (EMT) systems are often used to track the position and orientation of a navigation tool during navigated surgery operations. But, their sensitivity to field distortions originating from electromagnetic emitting devices or metallic objects present in the environment reduces measurement accuracy. The purpose of this study is to incorporate orientation information in correcting position data provided by EMT based on Hardy's Multi-Quadric method (HMQ). We implemented the HMQ algorithm in two ways: the basic form in which location data is used only and the modified form in which both the orientation and location data are incorporated into a normalized vector in the relevant formula. Comparing the corrected position data with their corresponding reference values, which are provided by the optical tracking system, it is observed that the mean global error is reduced approximately by half and the variance is decreased nearly to its one tenth.