Comparing two approaches of tactile zooming on a large pin-matrix device

Abstract

Zooming on large tactile displays can result in orientation loss, especially if the user’s reference point disappears from the visible area afterwards. To avoid such displacement we developed a focus zoom approach which keeps the currently focused element as central point for zooming. In this paper, we compare this approach with a conventional midpoint zoom (the center of the output area is maintained after zooming) on the touch-sensitive BrailleDis 7200 device. In a study with four blind and eight blindfolded sighted participants we could show that the focus zoom significantly reduces displacement of the focused element on the tactile output area. Locating the focus after doing a focus zoom needs significantly less time, reduces the overall workload and is also preferred by the users.