Haptic graphs for blind computer users

Abstract

In this paper we discuss the design of computer-based haptic graphs for blind and visually impaired people with the support of our preliminary experimental results. Since visual impairment makes data visualisation techniques inappropriate for blind people, we are developing a system which can make graphs accessible through haptic and audio media.The disparity between human haptic perception and the sensation simulated by force feedback devices is discussed. Our strategies to tackle technical difficulties posed by the limitations of force feedback devices are explained. Based on the results of experiments conducted on both blind and sighted people, we suggested two techniques: engraving and the use of texture to model curved lines on haptic graphs. Integration of surface property and auditory cues in our system are proposed to assist blind users in exploring haptic graphs.

Haptic Interaction Techniques for Exploring Chart Data

“…Unlike previous work ( [6], [8]), the representation chosen occupies the whole chart display (not only positive values) and in addition to the V-shaped line, some 'bumps' are added at the intersections of the V-shape line with the axes (see Figure 5). Figure 6 shows the data flow diagram of the museum tour scenario.…”

“…Initially, the line was represented by a cylinder or an embossed ridge, however, users found it difficult to follow the line without slipping off the edges [5], [6]. Fritz and Barner [5] used attraction forces to keep the user on the line.…”

“…However, Yu et al [6] proposed that engraved modelling should be used instead (also used by Van Scoy et al [7]). Representing different lines is still an open challenge.…”

“…Representing different lines is still an open challenge. Yu et al [6] used different surface friction to distinguish the lines, but this misled the users at line intersections. In addition, using gridlines to convey coordinate values, as with the visual counterpart, was found to be confusing.…”

Physically Interacting with Four Dimensions

“…Our fundamental techniques are based on a wide variety of prior art, including haptic interfaces focusing on virtual realism (see, e.g., [Baxter et al(2001) [Yu et al(2000)Yu, Ramloll, and Brewster]). Relevant methods of force feedback and user assistance include, e.g., the work of [Zahariev and MacKenzie(2003)], [Kennedy(2002)], [Forsyth(2004)], [Park and Niemeyer(2004)], and [C.W.Reynolds(1999)]).…”