The Functionalities and Technologies Trends in Developing Electronic Travel Aids for the Blind or Visually Impaired People: A Review

Abstract

In all parts of the community, basic autonomous navigation is essential. The capability to navigate complicated environments allows people to achieve a wide range of physical and mental objectives. With minimal non-visual infrastructure, indoor navigation is a complicated cognitive and perceptual activity, unlike Global Positioning System (GPS) infrastructure for outdoor navigation. Blind or visually impaired people (BVIP) require sophisticated technologies with inbuilt functionalities for obstacle detection and recognition and the identification of desired destinations like rooms, stairs, and elevators to better orient themselves and navigate in unfamiliar indoor environments. Electronic travel aids (ETAs) have developed and offered exceptional navigation support for the BVIP. ETAs increase opportunities for autonomous navigation by providing information regarding the surroundings in the indoor or outdoor environment, the user's present position, and navigational instructions about the route to a targeted destination. However, less focus has been found in the literature on integrating several functions in ETAs to have a more comprehensive system that supports indoor navigation activity of BVIP to facilitate the mobility of BVIP. This study provides a thorough review of previously developed ETAs using two main criteria: the used technologies and the fulfilled functions. Based on the review findings, this study suggests future research path of technological instrumentation for the BVIP' ETA solutions in indoor navigation.