Blog - Paper Reading #11

Multitoe: High-Precision Interaction with Back-Projected Floors Based on High-Resolution Multi-Touch Input

Authored by Thomas Augsten, Konstantin Kaefer, René Meusel, Caroline Fetzer, Dorian Kanitz, Thomas Stoff, Torsten Becker, Christian Holz, and Patrick Baudisch.

Augsten, Kaefer, and Holz are all students from the University at Potsdamn in Germany. Baudisch is a professor at the Hasso Plattner Institute where the remaining authors are students. This paper was published at the UIST '10 Proceedings of the 23nd annual ACM symposium on User interface software and technology.

Summary

Hypothesis
The authors believe that what they call frustrated internal total reflection can be used to design a highly sensitive foot-based input system. They also believe that today's touchscreen interfaces may be dramatically scaled upward using this concept.

Methods
The authors went through a series of user studies to make important design choices about their system. The first test measured how users activated buttons. This data was used to distinguish between neutral walking over the surface, and actions meant to trigger buttons. The second study analyzed how users could select controls from a honeycomb grid of buttons. Each user would stand on this grid and announce which button should be depressed based on their foot position. The third test measured a user's ability to manipulate a "hot spot", or a concentrated point on the surface. The final test examined a user's lower bound on the size of object that could be accurately interacted with.

Results
 The first user study revealed four useful types of input: tapping, double tapping, stomping, and jumping, with jumping being the most easily recognized. The authors also found that many users expected the whole area of their foot to be allowed for the purpose of selecting. Hotspot control varied highly from user to user, and reducing button size resulted in a reduction in accuracy. Although, it was found that some users preferred a medium keyboard to a large one in favor of the buttons being easier to reach.

Contents
This paper concerns a new method of registering touch based input to a touchscreen interface. Multitoe is built around a back projected floor utilizing frustrated total internal reflection. The paper describes several user studies that were carried out. The data yielded was used to construct the design parameters of Multitoe.

Discussion

 I found this to be a well written and interesting paper. The authors seem to have achieved their goals quite accurately. The users were able to effectively open menus and manipulate objects using the Multitoe system. I found no fault with this study other than its focus on the technology itself, but that was clearly stated in the introduction. The authors clearly outline potential future work. They are constructing a large scale FTIR surface to continue their studies of Multitoe. I don't know that this system will be useful in the same markets as current touchscreen interfaces, but I'm certain that there are niches for large-scale touch screens. Multitoe seems a viable first attempt at such a scaled up design.