Study On Hybid Motion Tracking Technology And Visualization For Augmented Reality Assisted Surgery Navigation

In order to improve the accuracy and safty of surgery by providing the space information of the surgical tools and the patients to surgeons, surgical navigation systems based on augmented reality are developed, which relate the medical images generated before or during the surgery operation to the motion of surgical tools and the patients, and then overlays the virtual models on the real surgical environment. In this paper, for the use of motion tracking in surgical navigation, the 3-DOF orientation tracking technology based on inertial sensors, the 6-DOF motion tracking technology based on optical-inertial sensor fusion approach and the AR surgical navigation technology based on 6-DOF motion tracking are developed. The approaches proposed in this paper provides a theory basement of the AR surgical navigation technology.1. An offline inertial tracking system is developed and the theory of orientation tracking is researched for augmented reality applications. To solve the drifting problem in orientation tracking with gyroscopes, a sensor fusion approach based on Kalman Filter is proposed, where an error model is defined. The experimental result shows that the orientation can be accurately tracked by the offline inertial tracking system. The drifting error, translating acceleration error and measurement noise from inertial sensors are compensated for by the Sensor fusion approach.2. A hybrid position and orientation tracking system based on optical tracking system and the inertial tracking system is developed for augmented reality surgical navigation. To compensate for the growing bias from the inertial sensors, a bias correction approach where the optical tracking result is used to correcte the inertial sensors measurement is proposed. To compensate for the patial occlusion problem in the optical tracking system, a sensor fusion approach based on the position of visible markers and orientation calculated with the inertial tracking system is proposed. To compensate for the total occlusion problem, a position and orientation tracking approach based on the bias-corrected inertial measurement is proposed. The experimental result shows that the sensor fusion approach can track the position and orientation with high accuracy, high updating rate and high robustness under conditions of long-term partial occlusion and short-term total occlusion.3. Augmented reality surgical navigation methods based on hybrid tracking system and augmented reality display are developed to enhance the surgical ability of surgeons. A side-view augmented reality display method is proposed to compensate for the calibration error between the surgeon’s sye and the display device. An error adaptive augmented reality display method is proposed to compensate for the failure of displaying the augmented reality images when tracking is stopped or influenced by errors. The experimental result shows that with the help of the surgical navigation system proposed in this paper, the surgeon can obtain the position and orientation of the patient and the tool.