Tactile Access to Scalable Vector Graphics for People with Visual Impairment

Martin Rotard, Thomas Ertl
Visualization and Interactive Systems Institute
University of Stuttgart
Universitätsstrasse 38
70569 Stuttgart
{rotard, ertl}@vis.uni-stuttgart.de

For visually impaired people Scalable Vector Graphics (SVG) provide a great opportunity to access graphical information. We propose an interactive transformation schema, which transforms SVG into a tactile representation. This paper describes how this transformation schema is realized and supported by navigation through the SVG shape hierarchy and by applying filters. Additionally meta information is extracted from the SVG and presented on the braille line and by voice output.

Images became standard in nowadays information publishing. The information presented in images must be accessible to all users. For users with visual disabilities it is necessary to access this information with non-visual devices. Scalable Vector Graphics (SVG) provide a great opportunity to explore graphics on tactile devices. Text, shapes, attributes, and meta information of SVG can be extracted easily.

Tactile output devices have a low spatial resolution (e.g. 120x60 or 24x16) and can display just monochrome output (pins up or down). We propose a transformation scheme, which makes it possible to display and to explore SVG on these devices. We developed a software environment, which can be used directly by blind users for exploring graphics as well as by developers to simulate several tactile output devices. The user can navigate in the graphics and apply filters. The tactile output is complemented by braille line and voice output.