1. Department of Engineering, Swarthmore College, 500 College Avenue, Swarthmore, PA 19081, USA,
2. Intel Research, 4720 Forbes Avenue Suite 410, Pittsburgh, PA 15213, USA
3. Google, Inc., Brandschenkestrasse 110, 8002 Zürich, Switzerland
4. Digital Human Research Center, National Institute of Advanced, Industrial Science and Technology, 2-3-26, Aomi, Koto-ku, Tokyo 135-0064, Japan
5. The Robotics Institute, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA
6. Google, Inc., 1600 Amphitheatre Parkway, Mountain View, CA 94043, USA