Blog #11

Multitoe: high-precision interaction with back-projected floors based on high-resolution multi-touch input

Authors:
Thomas Augsten Hasso Plattner Institute, Potsdam, Germany
Konstantin Kaefer Hasso Plattner Institute, Potsdam, Germany
René Meusel Hasso Plattner Institute, Potsdam, Germany
Caroline Fetzer Hasso Plattner Institute, Potsdam, Germany
Dorian Kanitz Hasso Plattner Institute, Potsdam, Germany
Thomas Stoff Hasso Plattner Institute, Potsdam, Germany
Torsten Becker Hasso Plattner Institute, Potsdam, Germany
Christian Holz Hasso Plattner Institute, Potsdam, Germany
Patrick Baudisch Hasso Plattner Institute, Potsdam, Germany

Proceeding
UIST '10 Proceedings of the 23nd annual ACM symposium on User interface software and technology

Summary

User input onto a touch interface using feet is studied. An apparatus using FTIR touch sensing, and projected images to a floor is tested. Participants are asked to test and give input on general ergonomics of the system.

Hypothesis

Since touch interface is limited to whats in "arm's reach" an interface using feet instead would have a much larger possible input area.

Methods

A back-projected surface using an input technology: frustrated total internal reflection or FTIR is used for input resolutions of 1mm. First, 8 participants were asked to show how they could walk over theoretical buttons without activating them, and then activate one with a different gesture based completely on their own ideas. Some ideas were less plausible than others since walking on heels can be difficult, or even dangerous. It was decided that a tap gesture is best for activation, and simply walking would be interpreted as not being any action.

The next test was to determine how tap gestures should be preferred, since the user may want to use their big toe, the ball of their foot, or the tip. It was found that each person could easily have a machine learned default position which helps the next step.

Users were asked to type on 3 different sized keyboard using tap gestures calibrated to each participant. the smallest keyboard measured 1.1cm, while the largest ones measured 5.3cm wide. The users were timed based on the start and end keys and each error is logged.

Another test of the system's usefulness included navigating a game using differing pressures on the feet with natural mappings to left, right, forwards, and backwards, as well as turning.

Results

Since the prototype was rather small, it did not show the full capability of the system. However, user input was done well enough to allow a small 3% error rate on the large keyboard test. Most of the users preferred the larger one, while a few preferred the medium sized keyboard.

Discussion

In my opinion, this prototype does not merit much attention, but the full scale system in development could have much more functionality though. My biggest issue with the paper is that most people simply don't have good eye-foot coordination. Other gestures could plausibly be made while barefoot but due to physiological limitations will still be a hindrance.