In the endoscopic surgical fields, much information which could be used intraoperatively is strongly demanded. We formulated a new magneto-optic hybrid 3D sensor configuration, and have developed an augmented reality navigationsystem using the accurate three dimensional sensor system that can be utilized in the endoscopic surgeries. This systemmeasures the 3D position of the tip of ultrasound probe in the abdominal cavity using magnetic 3D position tracker. Accuracyof the magnetic tracker is affected by metallic objects such as surgical tools that distort the magnetic field. We proposereal-time distortion correction of the magnetic fields using a magneto-optic hybrid 3D position tracker aiming to acquire theaccurate 3D ultrasound image. In this paper, we evaluated the effectiveness of the navigation system especially that of ourmethod of rapid distortion correction of magnetic fields in the operative environment. The error caused by magneticdistortion was reduced from 34.6mm to 2.59mm in position and from 9.08 degrees to 0.82 degrees in orientation. The timeto obtain the calibration data was 69 seconds. Three dimensional ultrasound imaging has the advantage that real time imagingis acquirable, regardless of organ shift or distortion. Our experimental results showed the proposed method was effective.
