The introduction of the white cane early in the last century gave blind and visually-impaired users a mobility tool that not only helped them to get around, but also allowed them to be seen by others. Now researchers from Sweden's Luleå University of Technology – the same place that designed the autonomous wheelchair – have developed and publicly tested a system which could potentially give wheelchair-bound blind people a virtual white stick to help them detect and avoid obstacles. An electric wheelchair has been fitted with a navigational laser scanner which provides virtual 3D maps of the surroundings, and sends feedback about any obstructions to the user via a haptic interface.
Using the time of flight technique, a pioneering navigational laser scanner developed by professor Kalevi Hyyppä of the University's EISLAB sweeps the area around the wheelchair to produce a virtual 3D map of the surroundings. This information is sent to a haptic interface, which allows the user to "see or feel" obstacles such as open doors, or pedestrians, and use the joystick to navigate past them without so much as a bump.
The first public test run was undertaken by the project's prospective PhD student Daniel Innala Ahlmark (who is himself visually-impaired), along one of the busy corridors of the University's Computer Science, Electrical and Space Engineering Department. He remarked afterward that he felt safe when using the system, and that it was just "like using a white cane."
The team – which also includes assistant professor Håkan Fredriksson and PhD student Fredrik Broström – admits that there are a few limitations to overcome before such a mobility tool could go into commercial production. The current laser scanning system, for instance, cannot register anything above and below the beam, so plans are underway to develop a 3D camera that will be able to produce multi-level virtual maps.
It is estimated that a more sensitive, production-ready system could be available within the next five years.
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