Paper Reading #24: Gesture Avatar, A Technique for Operating Mobile User Interfaces Using Gestures

Hao Lu is a computer science graduate student at the University of Washington.
Yang Li is a senior researcher at Google Research

This paper was presented at CHI 2011.

Summary
Hypothesis
The researcher's goal was to create a system that allows for the easy interaction with mobile interfaces.

Methods
To test their hypothesis, the authors set out to create a system called the Gesture Avatar system. To them, one of the main problems of current mobile interfaces is the small size of many interface elements. For example, small buttons that are hard to use or tiny links on a webpage that are hard to click.

To counter this problem, the Gesture Avatar system allows the user to draw a shape or a letter near the object the user wants to activate and the system let's the user control the object from this larger "gesture avatar".
For example, a slider might be hard to activate while on the move or it might just be too small. A user could draw a box close to the slider they want to control and then slide that box like the slider.
Another example is for selecting small texts or clicking small links on a webpage. By drawing the first letter of the link they're trying to activate, the user can then click on the letter and the system attempts to figure out what link is meant by the user.

To test their system, researchers used a Motorola Droid running the Android OS. They found 12 participants to test the system. They used two different tests. The first was a letter selection test. A small amount of letters would show up on the screen and the user would have to select the highlighted letter by drawing the letter gesture and select it. The next test was simply a target selection. They also had some participants walk and use the device and some were asked to walk on a treadmill and use the device.

Results


They used three different types of criteria to judge the Avatar Gesture system: time performance, error rates, and subjective preferences.

For all letter sizes, Gesture Avatar's performance time was about constant. It was significantly faster than an alternate system (Shift) on the 10 px letters however.

Error rates also remained low and about constant over the three target size tests. The error rates are SIGNIFICANTLY lower than the alternate Shift system.

In the subjective preferences, 10 out of 12 participants preferred Gesture Avatar over Shift.

Discussion
The Gesture Avatar system is certainly a novel system of controlling a device. One of the main problems with mobile interaction is the limited screen space of a device. Screen size cannot be increased without making the device larger. Thus, for cell phones, making a larger screen is not really a viable option when it comes to fostering better user interaction.

One problem that might arise from the system is the fact that they only tested the system using two hands. Often times, when I'm in a hurry walking down the street, I only used one hand on my mobile device. I would have liked to see what would happen if someone just used their thumb to draw the gestures as opposed to a whole new hand.