IR Sensor Provides 'Virtual Touch' for Blind

An IR sensor and the concept of virtual touch could help the visually impaired take on many day-to-day activities.

Researchers at the University of Cincinnati used an Enactive Torch, a tactile feedback device for experiments in sensory substitution, in tests to help visually impaired subjects navigate through doors, along busy sidewalks and perform other tasks that are typically difficult for them.

Created by a team based at the University of Sussex in England, the device uses two infrared rangefinders — one covers an outward range of 8 to 80 cm, while the other covers 20 cm to 150 cm. Its development was the subject of a paper published in IEEE Transactions on Haptics in 2012 (doi: 10.1109/TOH.2011.57).

The Enactive Torch uses infrared sensors to “see” objects. Courtesy of Colleen Kelley/University of Cincinnati.

When the device detects objects in its path, it vibrates through an attached wristband. The intensity of that vibration increases as the device gets closer to the object, allowing the user to judge how to react.

According to University of Cincinnati graduate researcher Luis Favela, “Results of this experiment point in the direction of different kinds of tools or sensory augmentation devices that could help people who have visual impairment or other sorts of perceptual deficiencies. This could start a research program that could help people like that.”

Favela presented his research at the American Psychological Association's annual convention.

The Centers for Disease Control and Prevention predicts a significant increase in those affected by blindness or low vision by 2030, related to an increase in diagnoses of diabetes and other chronic diseases, as well as the large, rapidly aging baby boomer population.

The Cincinnati study involved 27 undergraduate students with normal or corrected-to-normal vision who had not previously used mobility assistance devices. They were asked to make perceptual judgments when passing through an opening a few feet in front of them, but without changing their normal posture.

They were tested in three ways — using only their vision, using a cane while blindfolded and using the Enactive Torch while blindfolded. This allowed the comparison of judgments made with vision versus those made via touch, Favela said.

The researchers found that the subjects’ judgments in all three tests were equally accurate.

“When you compare the participants’ judgments with vision, cane and Enactive Torch, there was not a significant difference, meaning that they made the same judgments,” Favela said. “The three modalities are functionally equivalent. People can carry out actions just about to the same degree whether they’re using their vision or their sense of touch.”

In the next round of experiments, the researchers plan to study more complicated judgments, including subjects’ ability to step over obstacles and climb stairs, all while using the same three approaches.

“If the future version of the Enactive Torch is smaller and more compact, kids who use it wouldn’t stand out from the crowd, they might feel like they blend in more,” he said. “That bodes well, say, for someone in the Marines who was injured by a roadside bomb. They could be devastated. But hope is not lost. They will learn how to navigate the world pretty quickly.”

For more information, visit www.uc.edu.