The Math Description Engine Software Development Kit (MDE SDK) can be used by software developers to make computer-rendered graphs more accessible to blind and visually-impaired users. The MDE SDK generates alternative graph descriptions in two forms: textual descriptions and non-verbal sound renderings, or sonification. It also enables display of an animated trace of a graph sonification on a visual graph component, with color and line-thickness options for users having low vision or color-related impairments. A set of accessible graphical user interface widgets is provided for operation by end users and for control of accessible graph displays.

Version 1.0 of the MDE SDK generates text descriptions for 2D graphs commonly seen in math and science curriculum (and practice). The mathematically rich text descriptions can also serve as a virtual math and science assistant for blind and sighted users, making graphs more accessible for everyone.

The MDE SDK has a simple application programming interface (API) that makes it easy for programmers and Website developers to make graphs accessible with just a few lines of code. The source code is written in Java for cross-platform compatibility and to take advantage of Java’s built-in support for building accessible software application interfaces. Compiled-library and NASA Open Source versions are available with API documentation and Programmer’s Guide at

This work was done by Robert O. Shelton of Johnson Space Center, Stephanie L. Smith and Dan E. Dexter of L-3 Communications Corp., and Terry R. Hodgson of Indyne, Inc. For more information, download the Technical Support Package (free white paper) at under the Software category. MSC-24139-1

NASA Tech Briefs Magazine

This article first appeared in the May, 2010 issue of NASA Tech Briefs Magazine.

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