Opening Keynote of Mobile HCI by Patrick Baudisch

Patrick Baudisch presented the opening Keynote. He gave an interesting overview of work on interaction with small screen devices. It is very apparent that currently the form factor of devices is nearly exclusively determined by the I/O components. Throughout the examples it became very explicit, that the usefulness of a device for certain tasks it determined by the options for interaction. E.g. by increasing the input precision or by reducing the fat finger problem new tasks (and eventually new applications) will become possible on mobile devices. Patrick showed an example where he asks his students, to design a UI for a device as small as a one Euro coin (e.g. digital jewelry) - I think I borrow this idea for our next course :-)

How showed many examples of his work - too many to write it in a blog entry - but well documented on his web page. It is a page worthwhile to check regularly as his group is outstandingly creative and productive.

Patrick made an insightful analogy between small screens and theater stage, arguing that the both have a similar problem: the lack space to show everything you would like to show due to a constraint space. The solutions in the theater can give a good inspiration for designing mobile UIs. He mentioned three typical solutions used in the theater:

• Partially out of the frame - you show something only to a small part and the user's imagination will fill in for the rest. In the theater an example is a ocean liner where you only see a very small part but people imagine the rest. The halo visualization technique [1] is one example for this approach on a mobile device.
• In and out points - people enter and leave the stage at given points providing an illusion of a comprehensible world around the stage (and in the UI case around the screen)
• Direction of interaction to invisible targets - by talking/pointing/looking into a certain direction actors can create an impression of interacting with someone at a certain location - who is not really there and who's position is off the stage.

Technically I found the video he showed on using a depth cam extremely exciting. He speculated that this may solve many problems we have currently with using computer vision in difficult light conditions. In his example he showed the image recorded by a depth cam (based on time of flight) "filming" into direct sunlight - and as one would expect the sun does not matter. Looking forward to seeing some more results on this…

Looking at the current re-appearance of watch based computers and phones the idea of back side interaction becomes more and more interesting. In one design he showed how one can interact with a watch size device by interacting on buckle of the watch band. For more on back of device interaction see [2].

[1] Baudisch, P. and Rosenholtz, R. 2003. Halo: a technique for visualizing off-screen objects. In Proceedings of the SIGCHI Conference on Human Factors in Computing Systems (Ft. Lauderdale, Florida, USA, April 05 - 10, 2003). CHI '03. ACM, New York, NY, 481-488. DOI= http://doi.acm.org/10.1145/642611.642695

[2] Baudisch, P. and Chu, G. 2009. Back-of-device interaction allows creating very small touch devices. In Proceedings of the 27th international Conference on Human Factors in Computing Systems (Boston, MA, USA, April 04 - 09, 2009). CHI '09. ACM, New York, NY, 1923-1932. DOI= http://doi.acm.org/10.1145/1518701.1518995