A mobile electronic device is provided for use with a headset. A camera outputs digital pictures of a portion of the headset. A display device displays information for viewing by a user wearing the headset. A processor retrieves calibration parameters that characterize at least a pose of the camera relative to the display device, and processes a digital picture from the camera to identify a pose of an optically identifiable feature within the digital picture. A pose of the mobile electronic device is identified relative to the holder based on the identified pose of the optically identifiable feature within the digital picture and based on at least the pose of the camera relative to the display device as characterized by the calibration parameters. The processor controls where graphical objects are rendered on the display device based on the identified pose of the mobile electronic device relative to the holder.