Key Technologies Of Ultrasound Surgical Navigation Based On Optical Tracking System

Surgical navigation positioning technology includes optical tracking technology, mechanical positioning, electromagnetic positioning and other position technologies. Optical tracking technology has an advantage in anti-electromagnetic interference, flexible operation and small space occupation compared with other technologies, especially in the operating room. In order to avoid the radiation damage of X-ray and CT scans before operation and partial volume effect, the paper builds up a surgical navigation system based on optical tracking technology, which is fit for percutaneous puncture operation under ultrasound guidance. The paper mainly studys on camera calibration, needle tip point calibration, ultrasound probe calibration, needle and probe recognition and3D operation scene display.Firstly, a flexible camera calibration method based on three orthogonal constraints is presented for determining intrinsic parameters. At least2calibration images were captured to set up constraint equations according to orthogonal relationship. Thus, camera intrinsic parameters can be solved in the closed-form solution based on matrix eigenvalue decomposition. Experiments with both synthetic and real data show that our method has high accuracy and is robust.Secondly, a method based on matrix transitivity is presented for calibrating needle tip point and a method based on2orthogonal planes is presented for calibrating ultrasound probe based on optical tracking technology. Experiments with both synthetic and real data show that our method has high accuracy with1mm.Moreover, the paper designs two characteristics identification, and a recognition method based on the statistics of feature points color and area information from RGB space to HSV space is presented for distinguishing needle and probe. Results show that the method is effective and accurate with20frames per second, totally6feature points.Finally, after calibrating, tracking test, kalman filter target prediction, accuracy testing and multi-targets tracking test, the paper builds up surgical navigation demo system. The paper undergoes two simulation experiments which are single needle tracking experiment and multi-targets tracking experiment with supporting surgical navigation software.In the end, experiments show that the demo system meets accuracy and real-time requirements of surgical navigation.