Providing blind people with access to technical diagrams

This paper describes the operation and evaluation of a series of prototype systems that have been developed (as part of the EU-funded TEDUB project) to give blind people access to diagrams in well-defined technical domains: software engineering diagrams (UML), architectural plans and electronic diagrams. The prototype systems focus on how information (including logical structure and spatial relationships) can be conveyed to a blind user through the use of structured hierarchies and a variety of input and output modalities (including sound (2D and 3D) and force-feedback joysticks). The paper describes the context of the TeDUB project, the architecture of the prototype tools and the final system, and gives detailed evaluation results based on trials with over 20 users. The evaluation results show that connectivity and relative position can be effectively conveyed, but that the relationship between logical and spatial structure needs further development.