For people with reduced vision, getting around safely without walking into obstacles can be tricky. Those with decent central vision but whose peripheral sight is fading or lost are particularly at risk because they aren’t conditioned to be alert for oncoming dangers they can’t see.
But a new pocket-sized device that sits on a person’s chest may make walking much safer for these people and others with visual impairments by warning of impending collisions. The warning system is based on an estimate of time to collision rather than proximity. The idea behind this is that an object is not a threat if someone is simply standing close to it, perhaps a flawed assumption if you consider how often we hit our heads or stub our toes on unseen objects while turning around. If something is headed for you, or if you’re about to walk into something, the device issues a warning beep.
Researchers from Massachusetts Eye and Ear at Schepens Research Institute tested the device on 25 patients with tunnel vision or hemianopia (a form of blindness that occurs over half the field of vision). The patients walked a 41-m (135-ft) loop-shaped obstacle course filled with oncoming pedestrians and 46 stationary obstacles positioned at a variety of heights. While wearing the device, collisions were reduced by 37 percent and patient walking speed only changed slightly.
This is far from the only attempt to help visually-impaired people navigate their environments without collision. In 2009 we saw a prototype system that converts digital video from head-mounted cameras into a three-dimensional acoustic map. Meanwhile, the Tacit mounts to your wrist and provides haptic feedback as it senses objects near and far through sonar pulses. There are also walking canes with built-in tech that augments their conventional usefulness and Bluetooth beacon systems that sync with a smartphone and act as proximity sensors for blind people as they navigate public or private environments. There are even robot guides that function like guide dogs in stair-free environments.