Speech-filtered bubble ray: improving target acquisition on display walls

The rapid development of large interactive wall displays has been accompanied by research on methods that allow people to interact with the display at a distance. The basic method for target acquisition is by ray casting a cursor from one's pointing finger or hand position; the problem is that selection is slow and error-prone with small targets. A better method is the bubble cursor that resizes the cursor's activation area to effectively enlarge the target size. The catch is that this technique's effectiveness depends on the proximity of surrounding targets: while beneficial in sparse spaces, it is less so when targets are densely packed together. Our method is the speech-filtered bubble ray that uses speech to transform a dense target space into a sparse one. Our strategy builds on what people already do: people pointing to distant objects in a physical workspace typically disambiguate their choice through speech. For example, a person could point to a stack of books and say "the green one". Gesture indicates the approximate location for the search, and speech 'filters' unrelated books from the search. Our technique works the same way; a person specifies a property of the desired object, and only the location of objects matching that property trigger the bubble size. In a controlled evaluation, people were faster and preferred using the speech-filtered bubble ray over the standard bubble ray and ray casting approach.