Recently, the number of people with visual impairment in the world is dramatically increasing. These blind people utilize walking assistance devices in order to find their way to the place of interest. Studies on walking aids for blinds have been widely performed. Most of walking aid devices utilize ultrasonic sensors, which have two main advantages. First, the sensors have competitive price compared with other walking aids. Second, they are easy to implement and they provide reliable performance in terms of distance measurement.
Therefore, researches on walking assistance devices based on ultrasonic sensors have been actively executed for the blind. The ultrasonic sensors are used for in various forms such as canes, glasses, clothes and mobile robots for the blind. In spite of many advantages of the ultrasonic sensors, there is little study on performance analysis of the glasses which use ultrasonic sensors. Especially, the performance analysis of glasses with different arrangement of the ultrasonic sensors is required.
In this paper, we analyze the performance of glasses using ultrasonic sensors with variable sensor placement and combination. The evaluation focuses on the sizes of obstacle detectable area, obstacle direction determinable area and blind area. We use two types of ultrasonic sensors with different beam angle. Using this ultrasonic sensors array, obstacle detectable area and blind area information are obtained every 25cm interval from the blind. AutoCAD 2010 is used for the obstacle detectable area analysis.
From the performance analysis, we show the change of detection ability of glasses according to the type, number, and the arrangement of the ultrasonic sensors. This analysis results can be used as fundamental data for designing glasses with ultrasonic sensors for the blind.