Filtering And Calibration For FASTRAK Data And Its Application In Virtual Surgery

Virtual Surgery is to utilize various kinds of medical image data and virtual reality technology to build and set up the simulation environment in the computer. With the help of the information about virtual environments doctors can plan an operation, have training, and hold an operation under the Virtual Surgery's guiding in the course of actual operation. Virtual Surgery adequately incarnates the use of virtual reality technology as a role of computer graphics in medical science and fully reflects the third dimension and immersion of human-computer interaction. Interactive technology is the key technology of virtual surgery, developing an appropriate scheme is related to the success of the virtual surgery system. It is the best choice to introduce the interactive equipment as the same as the real operation equipment.In the development of virtual arthroscope surgery system we use an electromagnetic tracking device FASTRAK as an arthroscope to locate and realize interaction and in the development of virtual surgery system of cardiac intervention we simulate tutors and instructors with the receivers of FASTRAK. But the inherent electromagnetic characteristics of FASTRAK for environments is harsh, all like CRT monitors, metal objects, ceilings, walls and etc. will disturb the data of FASTRAK. In this article we analyze all possible factors which can cause the noises and affect the stability and precision of FASTRAK data. We also describe the noise model which may result in the disturbance electromagnetic filed. Aiming at the deficiency of the existing method of calibrating the FASTRAK data, combining the actual need in the subject, we propose the model based on band-pass filter of FASTRAK data and realize the algorithm in the software system developed. The experimental result of simulation indicates that the calibration model of filter algorithm performances well. We also compare and analyze FASTRAK data under different environments, the results show that it is good that the band-pass filter based on FFT gets rid of the noise of FASTRAK and it is robust too.The research of this article is centralized on the interactive technology of virtual arthroscope surgery and virtual surgery of cardiac intervention. The resolving scheme is presented in order to filter the noise in FASTRAK application environments with complicated noise, which establishes a foundation for more developing and generalizing the virtual surgery system.