Grid Map Correction for Fall Risk Alert System Using Smartphone

Abstract

In this work, we have incorporated an electronic travel aid (ETA) as a smartphone application that alerts fall risks to the visually impaired. The application detects negative obstacles, such as platform edges and stairs, and occlusion using a grid map including height information to estimate fall risk based on the distance from an area’s edge to the user, and the area ratio. Here, we describe a grid map correction method based on the surrounding conditions of each cell to avoid area misclassification. The smartphone application incorporating this correction method was verified in environments similar to station platforms by evaluating its usefulness, robustness against environmental changes, and stability as a smartphone application. The verification results showed that the correction method is, in fact, useful in actual environments and can be implemented as a smartphone application.