Obstacle Classification through Acoustic Echolocation: A wearable obstacle detection and classification system for visually impaired persons

Abstract

A visually impaired parson comes across objects with different attributes in his navigational path, and all of those objects can t be considered as obstacles. One person s obstacle could become a landmark for another. Therefore, getting some insights about the features of the obstacles that come across will provide a significant impact on improving the navigational process of the visually impaired individuals. In this study, an innovative wearable obstacle classification system which extends the currently available obstacle detection approaches using sonar echolocation to extract useful information about the obstacles while doing a basic obstacle classification, has been developed. In order to increase the detection range and to improve user-friendliness, an innovative approach based on integration of electronics onto textiles and wearable spectacles has been studied. Optimum architecture to embed electronic equipment s and sensors to the textile has been studied. Finally, a smart clothing and spectacles prototypes including ultrasonic sensors, vibration motors, power supplies and a micro controller has been developed. The working principle of the system is based on three main functions: sensing the surrounding environment via sonar sensors as well as classifying the detected obstacles into some meaningful set of classes and guiding the user to navigate through the environment by avoiding obstacles while giving the feedback of the characteristics of the obstacles comes across. The accuracy of the above functionality of the system was evaluated in unfamiliar indoor environments by using visually impaired individuals where extensive evaluations were carried out to check the classification accuracy of the system in three main aspects: classification of standard indoor target types, ground level obstacle types and complex target types as well. The evaluation results together with the feedback of the visually impaired individuals has proven that the proposed wearable smart prototype systems could become united part of visually impaired people s lifestyle, and it could help them overcome navigation concerns seamlessly, if the few drawbacks of the system like power consumption and cumbersomeness could be addressed further.