New Tracking Method for Head Motion Using a Single Camera and a Solid Marker

We propose a new method for measuring the orientation angles of rigid body motion (e.g., that of a human head) for medical applications. This method employs one optical camera and one solid marker, unlike the conventional method, in which two or more cameras and markers are used. We expect that this method should be useful when the subject is placed in a long,narrow space and the conventional method cannot be employed. In this report, we describe the principles of our new motion measurement method and discuss theresults of experiments to evaluate the tracking accuracy. We demonstrate that the RMS accuracy for the orientation angle is on the order of 0.5 degrees and that this method is therefore suitable for head motion correction in positron emission tomography(PET) brain imaging