Vulture: A Mid-Air Word-Gesture Keyboard

Anders Markussen                       Mikkel Rønne Jakobsen                            Kasper Hornbæk
  amark@diku.dk                               mikkelrj@diku.dk                                   kash@diku.dk

                        Department of Computer Science, University of Copenhagen

                   Njalsgade 128, Building 24, 5th floor, 2300 Copenhagen, Denmark 

Summary

Word-gesture keyboards enable fast text entry by letting users draw the shape of a word on the input surface. Such keyboards have been used extensively for touch devices, but not in mid-air. The paper present vulture, a word-gesture keyboard for mid-air operation. 

Vulture is a text entry method using word-gestures in mid-air: By moving the hand, the user places the cursor over the first letter of the word and (1) makes a pinch gesture with thumb and index finger, (2) then traces the word in the air—the trace is shown on the screen. (3) Upon releasing the pinch, the five words that best match the gesture are proposed; the top match is pre-selected.

They have conducted two studies, study 1 was designed to estimates the potential of a WGK in mid-air. Study 2 aims to compare the performance of WGKs in mid-air and touch. 

1. The empirical results from two studies show clear usability benefits compared to existing mid-air text-entry methods;

2. The key issue in designing for mid-air interaction is that input space and output space are separated, which seems to make interaction more mentally demanding.

3. Participants’ gesture movements in mid-air text entry were slower, but with same accuracy as in touch-based text entry.

4. Visual feedback is important but also limits performance.

Discussion: 

1. Do you think mid-air word-gesture keyboards are practical?

2. Do you think it will replace touch keyboard?

3. If you are designing the mid-air word-gesture keyboard,  how would you design it? Can you think about any more effective way to design this?

Few questions has been raised from the class discussion. People think mid-air gesture keyboards are not practical due to they might not comfortable with moving their hands in mid-air and also consider about the hand fatigue. The paper also suggested a number of scenarios such as work in sterile conditions (e.g., operating theatres), in augmented reality (e.g., with Google Glass), and when writing on public displays. According to the feedback from the class, it would be better to use voice control rather than mid-air WGK in sterile conditions. Furthermore, the correctness of WGK also would be the barrier for people to use, because it cannot be used for typing other language except English. And sometimes, the similarity of word shapes will effect its ability to recognize.

Link to presentation slides:
https://docs.google.com/presentation/d/1YbFT5WbqEpUcfkZ-5tMdKbGcXg7PmGL76bHtJf7xkJg/edit#slide=id.p