Description

Much of the sciences involve visualization of materials and concepts. This can present an extra challenge to persons who are blind and visually impaired because materials used to convey these concepts are often images and are not readily accessible to them. To date there is no simple and efficient way of interpreting or producing models of images conveyed in texts, and on the computer. Three dimensional models may be generated through casting or stereo lithography techniques. Two dimensional raised line drawings can be produced through similar techniques. In general, these methods along with Braille transcriptions require much lead time, and can be very expensive.

This project develops a composite software/hardware system for automatic translation of electronic images into tactile form. In this system, an aggregate process comprised of a sequence of image processing algorithms is applied to an image to produce a simplified version of the original. This caricaturized image is subsequently output in a raised tactile graphic from on microcapsule paper, suitable for display to a blind person.

The technique in which the tactile graphic is produced is optional. The software developed is intended to provide a way to generate tactile images quickly and easily. To produce the physical tactile model, we use the microcapsule paper. In this manner the process of rendering a meaningful tactile image of a picture, from filtering an electronic image to producing a hard copy in tactile form on microcapsule paper, takes only a matter of minutes. The process is illustrated below.

The image is filtered with our software, and Xeroxed onto microcapsule paper. The microcapsule paper is then fed through the Image Enhancer (Reprotronics, Inc.) to produce the raised image. The image being tactilely rendered is that of an Ebola virus.

As the bandwidth of the visual sense is orders of magnitude higher than the tactual sense, the tactile rendering software is being designed to produce detail of the image in varying levels. Multiple tactile versions of the image in question can be generated, allowing one to feel the most prominent features and then hone into more of the subtler details.

Considerable research has been done over many years toward the development of a refreshable dynamic tactile graphics display, using technologies such as electrorheological fluids and nickel-titanium shape-memory wire. However, none of the efforts have produced a viable display to date. Ultimately, this tactile rendering software in conjunction with a dynamic tactile display would allow for the visually impaired much improved access to tactile interpretations of image based information.

Project Schedule

References

• Tactile Graphics: An Overview and Resource Guide - John Gardner, Oregon State Univ., 1996.
• Design of a Tactile Graphic Tablet - Joerg Fricke and Helmut Baehring, Fern Universitaet Hagen, 1990.
• EASI - Equal Access to Softwaren and Information - web site with many references.
• Dee's List of Graphics and Tactile Displays - links for people with visual impairment or blindness.
• Tactile Graphics Resources - near-definitive list of most important links.
• Pins Down Tactile Imaging System - NIST prototype full-page tactile display with static pins.

updated 12/27/04