Realtime markerless rigid body head motion tracking using the Microsoft Kinect

Accurate and reliable head motion tracking is essential to enable robust motion correction of brain Positron Emission Tomography (PET). Systems such as the Polaris Position Sensor offer high spatial and temporal resolution, < 1mm at 20Hz, tracking of a tool which is attached to the head. It is difficult to rigidly fix the tracking tool to the patient without discomfort which results in unreliable data due to tool slippage. An open-source, markerless, tracking system using the consumer grade Microsoft Kinect is presented which provides realtime motion tracking of the head at 30Hz. Realtime tracking is achieved using a general purpose graphics processing unit (GPU). The tracking algorithm is insensitive to changes in facial expressions and partial occlusions. Phantom and human data is presented comparing the tracking offered by both the Kinect based and Polaris system.