A Study on The Factors for Improving Performance of The Stereo Camera for The TMS Navigation System

Transcranial Magnetic Stimulation (TMS) applying magnetic stimulation directly on neurons of the brain noninvasively is being used to treat stroke, Parkinson’s disease, depression, and so on. TMS can provide treatment through more effective stimulation when accurate stimulation is applied to an anatomical position of the patient. So a navigation system for obtaining accurate information about location is necessary for effective stimulation. The TMS navigation system is composed of a transducer, an infrared stereo camera, and an infrared marker attached to the patient’s head. The stereo camera provides real-time information about location of the infrared marker attached to the patient’s head and the transducer, and with the information, the patient’s head and the transducer, both of which are on real-time movement, are located by using time-delay algorithm, space intersection, camera calibration, and inner elements of the camera. This location information is crucial in that location of the transducer and the patient varies according to precision of the stereo camera module. In this study, we used two different models of WebCam to make a comparison of distortion and FOV and examine those factors for improving performance of the stereo camera with the objective of improving accuracy of the TMS navigation system.