A Video Based Tracker for use in Computer Aided Surgery

Recent improvements in medical equipment and data visualisation tools have made it possible for surgeons to use medical images of patients during operations as well as during the preparation phase. In order to use the data effectively in the theatre the surgeon must be given live information about his current location inside the patient relative to the pre-operative images. This paper describes a vision-based system that can locate and track a passive hand-held instrument in the operating theatre to provide the real-time information required. A target acquisition system is described which locates a pre-defined object in an arbitrary scene and calculates its 3D location and attitude. Enhancements to the RAPiD model-based tracking system are also detailed including multiple camera operation, improvements to edge identification in the image and combining robust tracking with high accuracy. Experimental results are also provided.