Blog #12: Multitoe: High-Precision Interaction with Back-Projected Floors Based on High-Resolution Multi-Touch Input

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


Authors: Thomas Augsten, Konstantin Kaefer, Rene Meusel, Caroline Fetzer, Dorian Kanitz, Thomas Stoff, Torsten Becker, Christian Holz and Patrick Baudisch


Author Bios:
Thomas Augsten is pursuing Masters in IT Systems at the University of Potsdam in Germany.


Konstantin Kaefer is pursuing Masters in IT Systems at the University of Potsdam in Germany.


Rene Meusel is a student at the Hasso Plattner Institute.

Caroline Fetzer is a student at the Hasso Plattner Institute.


Dorian Kanitz is a student at the Hasso Plattner Institute.


Thomas Stoff is a student at the Hasso Plattner Institute.


Torsten Becker is a student at the Hasso Plattner Institute.


Christian Holz is a student at the University of Potsdam pursuing a Ph.D. in HCI.


Patrick Baudisch is a student at the University of Potsdam pursuing a Ph.D. in HCI.




Presentation Venue: This paper was presented at UIST '10 Proceedings of the 23rd annual ACM symposium on User interface software and technology in New York.


Summary:
Hypothesis: The authors here propose creating direct touch surfaces that are orders of magnitude larger. They approach this challenge by integrating high-resolution multitouch input into a back-projector floor. At the same time, they maintain the purpose and interaction concepts of tabletop computers, namely direct manipulation. They have based their hardware design on frustrated total internal reflection. The prototype's ability to sense per-pixel pressure allows the floor to locate and analyze user's soles. They demonstrate how this allows the floor to recognize foot postures and identify users. These two functions form the basis of the systems of their prototype. They allow the floor to ignore users unless they interact explicitly, identify and track users based on their shoes, enable high-precision interaction, invoke menus, track heads, and allow users to control high-degree of freedom interactions using their feet. 
How the hypothesis was tested: The authors tested their prototype by performing multiple experiments using participants.

How to not activate a button: This study was performed to help design a mechanism that allowed the floor to distinguish intentional user action from regular walking and standing (intuition). Te interface was implemented using four paper buttons taped to the floor. The participants walked across the four buttons and were tasked to "activate" the two 'cancel' buttons and get across the 'ok' buttons without activating them.
Participants: 30 --> 6 female 24 male
Results: Tapping for activation


Invoking a menu: Maximum number of participants used the "jump" action to invoke a menu


Conceptual model of stepping: This study was performed to understand which area of the user soles are active and should be thus considered in hit testing. For this experiment, the participants stepped onto the multi-touch floor with their dominant foot wearing shoes.
Participants: 20 --> 6 female 14 male
Results: 8 of 20 participants set every button at least a certain percentage of which was covered by the projection of the participant's shoe.


High-Precision Pointing with Hotspot: The purpose of this study was to survey what point on the users' shoe (hotspot) was used to interact with point targets. Participants wearing shoes stood on a waiting position marked with circles. For each trial, a target marked with crosshairss appeared 30cm in front of the user. Users placed their preferred foot onto the crosshairs, such that the foot's hotspot was located directly over the crosshairs.




Discussion:
Effectiveness: In this paper the authors presented high-resolution FTIR (Frustrated total internal reflection)- based floors  as a means to create interactive multi-touch surfaces beyond the size of tabletop computers. They made first steps toward enabling the interaction model of touch (direct manipulation) on such a floor. Combining high-resolution FTIR with a projected floor also resulted in the design of additional interactions. One of them is user identification based on sole patterns. 
Reasons for being Interesting: This paper is really interesting to me as the authors perform multiple tests on the participants and contribute those results to develop algorithms  that would make it possible for the users to control input devices keeping their hands free.
Faults: There are no reported faults in this paper since the prototype is using algorithms using the user participation survey. However, I personally think that this idea is very effective for controlling tasks like playing music, selecting songs, forwarding then, selecting pictures etc. However, a function such as typing using one's foot would result in a strenuous physical activity as compared to efficiently inputting data on a given space.