From pixels to taxels—a new world of opportunities for the blind

Medical Xpress

21st September 2017

From pixels to taxels—a new world of opportunities for the blind

Digital technologies evolve at an incredible pace. Yet, they are still leaving people behind: visually-impaired people, for example, are completely locked out from the use of touchscreen devices. A European Union-funded consortium has therefore created the BlindPAD to exploit and enhance their remaining senses.

At the heart of the BLINDPAD (Personal Assistive Device for BLIND and visually impaired people) project was a single question: How can graphical contents be made accessible through touch? With current technologies essentially relying on visual user interfaces and graphical information, the sense of touch has been neglected, and the need for tactile technologies to facilitate the inclusion of visually-impaired people in modern society has never been so important.

As Dr Luca Brayda, researcher at the Robotics, Brain and Cognitive Sciences Department of the Italian Institute of Technology, explains, the BlindPAD aims to become to digital graphical information and communication what Braille is to text.

What are the main problems with current technology and its use of (or lack thereof) the sense of touch?

Blind people need to use the residual sense of touch to understand information – something not at all achieved for graphics. Overcoming that issue would require the fabrication of a tactile tablet for blind persons, which has been a challenge for decades. This is the concept of ‘sensory substitution’: Much like pixels, one digital image can be formed by a grid of small tactile pins (‘taxels’) that can be programmed to be ‘up’ or ‘down’, therefore forming a bas-relief that can be sensed and understood with the hands.

However, making a dense array of taxels with sufficient force and displacement to be easily felt by any user – that is also low power, fast and compact – is a major technological challenge. Due to the complexity of drive electronics or the lack of performance of actuators, none of the previous technological solutions was shown to be scalable, have sufficient performance and be portable.

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