The other evening I started reading Wayne Westerman's doctoral thesis on "Hand Tracking, Finger Identification, and Chordic Manipulation on a Multi-touch Surface" which was written in 1999. Dr. Westerman went on to found "FingerWorks" a company that manufactured and sold a multi-touch tablet called the iGesture and several other multi-touch products based on technology created by Westerman and Dr. John Elias. In one section, Westerman describes different methods for detecting multiple finger touches on a surface, and I literally laughed out loud when I read this almost perfect description of Microsoft Surface:
Another approach is to place a camera under a translucent tabletop and image the shadow of the hands [81, 110]. Unfortunately the bulky optics under the table will limit portability and leg room...
p. 38 of the thesis, or p. 68 of the PDF document
Strictly speaking though, Microsoft Surface doesn't look for shadows of the
hands, instead near infrared lights are mounted under the surface as well as
cameras which pick up the reflected light from fingers in contact with the
translucent top. But still, his point about limiting portability and leg
room are dead on. Westerman doesn't go as far as to call it a
ass table, but he does describe more limitations of using cameras to
And remember, this was written way back in 1999. Also, many of you
might be interested to know that a few years ago, FingerWorks was purchased by
Apple, and I have no doubt that Fingerworks technology is in the iPhone and
will probably be in a muliti-touch Apple tablet computer or multi-touch Cinema
Display within a year or two.