Comparison of methods presenting contour information to individuals who are blind or visually impaired

Graphs and charts are frequently used in school, work and everyday living. However, traditional techniques of providing this information to individuals who are visually impaired are cumbersome and slow. Refreshable tactile displays have been developed and used to display line graphs, bar graphs and pie charts. In this paper, we investigate the use of a haptic matrix-like display that can produce multiple amplitude levels and multiple frequencies for displaying contour plots. Experiments were performed to compare performance and usability for the two different methods. According to preliminary results, the use of amplitude variation provides the user with a more accurate awareness of contour level differences than frequency variation.