Electronic eye helps blind people across the street

Navigation system detects pedestrian crossings and traffic light phases

Crosswalk © Hermera
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A new "eye" could give millions of blind people around the world new mobility. The navigation system, developed by Japanese researchers, is designed to allow blind people to cross even busy roads safely and without assistance from others. The core of the system is a miniature camera connected to a computer chip, which, attached to a pair of glasses, can locate zebra stripes as well as identify the traffic light phases and convert both into speech.

Although some traffic lights are already equipped with acoustic signals for the blind, they are still in the minority. Crossing the street is therefore often still a risk for non-sighted people. Where there is a traffic light or even a zebra crossing, and how wide the road is, is usually not recognizable for them without outside help.

Now, Tadayoshi Shioyama and Mohammad Uddin of the Kyoto Institute of Technology have developed a system in Japan that uses a camera and two other devices to enable the blind to safely and independently cross a street. Professor Shioyama explains, "The camera is mounted at eye level and connected to a tiny computer. It transmits the information using a voice module and gives audible hints and information through a small speaker near the blind man's ear.

Already last year, the scientists had presented a computer-aided camera that can accurately determine the length of a pedestrian crossing except for the step. This is achieved by capturing an image of the white lines that mark an overpass and using geometry to determine the distance between them and their numbers. At the same time it can also recognize the traffic light phase. However, the system at that time could not determine where such an overpass was.

This decisive progress has now succeeded the researchers. To do this, they used a special calculation method known as "projective variance, " which measures the distance between the white lines of a roadway and a set of linear points on the edge of white lines and calculates whether there is a pedestrian crossing in the captured camera image or Not. The scientists tested this technology on 196 shots of street scenes and in 194 of them, the over-road detection was successful. The two misjudgments were unrecognized pedestrian walks. display

(Institute of Physics, 29.11.2004 - NPO)