Event Recognition during the Exploration of Line-Based Graphics in Virtual Haptic Environments

Pictorial representations are widely used in human problem solving. For blind and visually impaired people, haptic interfaces can provide perceptual access to graphical representations. We propose line-based graphics as a type of graphics, which are suitable to be explored by blind and visually impaired people, and which can be successfully augmented with auditory assistance by speech or non-verbal sounds. The central prerequisite for realizing powerful assistive interaction is monitoring the users' haptic exploration and in particular the recognition of exploratory events. The representational layers of line-based graphics as well as of exploration-event descriptions are specified by qualitative spatial propositions. Based on these representations, event recognition is performed by rule-based processes.