An application to modeling motion capture data (Taylor, Roweis & Hinton, 2007)
	• Human motion can be captured by placing reflective markers on the joints and then using lots of infrared cameras to track the 3-D positions of the markers. • Given a skeletal model, the 3-D positions of the markers can be converted into the joint angles plus 6 parameters that describe the 3-D position and the roll, pitch and yaw of the pelvis. – We only represent changes in yaw because physics doesn’t care about its value and we want to avoid circular variables.