Simultaneous multiple kinect v2 for extended field of view motion tracking

Markerless motion tracking is an attractive technique to monitor subject motion during Positron Emission Tomography, PET, imaging. Consumer grade depth sensors such as the Microsoft Kinect v2 offer a low cost solution to obtain the 3D position and orientation of a subject's head during brain PET. This tracking can be performed in real time at 30 Hz by registering of all the depth points measured by the Kinect v2 to an initial template, as implemented in the KinectFusion [1] iterative closest point, ICP, algorithm. Due to USB 3.0 bandwidth constraints, it is only possible to connect a single Kinect v2 to a PC. In this work, depth data from a second Kinect v2 is sent over a gigabit ethernet connection, and is incorporated in parallel with the KinectFusion tracking application. This enables tracking to be performed from the two viewpoints of the two Kinect v2 cameras which are spatially calibrated using square markers fixed to a 3D printed phantom. Finally we introduce a process by which Multiple Kinect Fusion allows for head motion tracking to continue in the case where partial and complete occlusions of the face occurs.