It is still recognized as a challenge task while blind and visually impaired people travel outdoor independently, even if there are a number of assistive mobility aids available. In addition to building universal facilities in urban and rural environments for them, it is essential to develop novel mobility assistive technologies and systems to satisfy their increasing demands for mobility. To investigate those demands, an international survey with 106 blind and visually impaired people from 13 countries is undertaken within this work, with regarding to outdoor mobility experiences, usages of mobile devices and collaborative approaches.

From the field of Human-Computer Interaction (HCI) and Accessibility, the dissertation focuses on enhancing blind people’s capabilities of acquisition of spatial environmental information from tactile displays. The spatial environmental information, in this study, is in terms of clusters of surrounding obstacles, geographic information on city maps, and information on environmental accessibility.

In order to non-visual representation of the clusters of surroundings obstacles detected by a 3D Time-of-Flight (ToF) infrared camera, a portable pin-matrix display with a matrix of 30 x 32 pins is employed and a pre-designed set of tactile obstacle symbols is used to render the properties of obstacles (e.g., type, size).

Additionally, aiming at helping blind people access geographic information, a desktop based pin-matrix display (an array of 60 x 120 pins) and a mobile pin-matrix display (an array of 30 x 32 pins) are used to represent a large-scale city map and a location-aware city map, respectively. A set of tactile map symbols rendered with the raised and lowered pins, has been designed for rendering various map features.

To allow blind and visually impaired people to acquire information on environmental accessibility, besides a traditional web browser client and a popular smart phone client, an audio-haptic client on a tactile display with 7200 pins is developed. Users are able to create and share collaborative annotations on environmental accessibility across the 3 clients.

The proposed approaches about non-visual representation of obstacles and map features by tactile symbols on pin-matrix displays, will contribute to the fields of accessible tactile graphic well, especially in the coming era of affordable pin-matrix displays. Meanwhile, the collaborative approach for improving environmental accessibility will encourage the society to raise the floor of accessibility for all. A number of further studies can be continued based on the current findings within this work, aiming at enhancing mobility aids for blind and visually impaired people gradually.

Full Thesis:
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Thesis Advisor:
Gerhard Weber & Ulrike Lucke

Award Date:
November 27, 2013

Technische Universität Dresden
Dresden, Germany

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