Virtual Cane Helps with Orientation

With new radar-based systems, visually impaired people like bats can find their way around.

virtual cane
Like a torch, you hold the virtual cane. © RUB, Kramer

In the immediate vicinity of the blind stick provides information about the environment, but where in the distance, the passage between houses fronts, he does not show. This can be radar-based systems developed by the Ravis-3D project consortium. The systems, which are intuitively usable, capture the environment and translate it into audio signals that are output via a semi-open hearing aid. Three chairs of the Ruhr-Universität Bochum (RUB) and several industry partners have completed the three-year project, which was funded by the European Union and the state of North Rhine-Westphalia.

Sensors, antennas, audio

The consortium initially set out to develop the technically feasible. So they built different radar systems, ranging from rotating 360-degree sensors on special antennas, which capture the field of view of the user, to directional sensors that measure the distance of a focal point. The researchers also used the box of tricks for the audio output of the environment: for example, the system analyzed the noise environment and then blocked out the obstacles that even emitted sounds.

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Accurately integrate into the acoustic environment

“Acoustically active obstacles, such as a speaking person, should not be seen as an obstacle to the system, since the user is already aware of it”, explains Prof. Dr. med. Rainer Martin from the Department of Communication Acoustics at the RUB. By surveying the individual hearing ability of users, the spatial location of sources has been further improved. “In doing so, we wanted to ensure that the setting of real obstacles or navigation instructions was integrated as precisely as possible into the users’ natural acoustic perception,” says Prof. Dr. med. Gerald Enzner from the RUB communication acoustics.

The more intuitive the more popular

The research team developed different sensors and systems for the project and tested them together with stakeholders. “The amazing thing was that it was the simple, intuitive systems that provided the most positive user feedback,” says Prof. Dr. med. Nils Pohl, holder of the Chair of Integrated Systems of the RUB.

The demonstrator shows how the system works: The environment is scanned by radar. The sound is presented to the user via a hearing aid.© RUB, Kramer

This, in turn, was of particular interest to the companies Kampmann Hörsysteme and “Sensor-based Neuronal Adaptive Prosthetics”, Snap for short. Their task was to test the systems with those affected and to integrate hearing aids for audio output. One of the main advantages of this system is that it is a relatively simple sensor system that can be held in one direction like a flashlight to give the distance to the next obstacle as sound. “In conjunction with the audio output via hearing aids, this results in an intuitively operated virtual blind stick that works within a longer range”, explains Dr. med. Corinna Weber from the company Snap.

Great marketing potential

The members of the consortium are confident that the results of Ravis-3D have great marketing potential. “Such a system is not yet available on the market,” says Dirk Kampmann of Kampmann Hörsysteme, which manages the consortium. “We now have to work to make the components smaller and cheaper, and that the system fits in well with other IT-based tools for the blind, for example, on smartphones. If that succeeds, we can enrich the market for aids for the blind in the coming years. “