Route planning methods in indoor navigation tools for vision impaired persons: a systematic review.

Route planning is key support, which can be provided by navigation tools for the blind and visually impaired (BVI) persons. No comprehensive analysis has been reported in the literature on this topic. The main objective of this study is to examine route planning approaches used by indoor navigation tools for BVI persons with respect to the route determination criteria, how user context is integrated, algorithms adopted, and the representation of the environment for route planning. A systematic review was conducted covering the period 1982–July 2018 and thirteen databases. From the 1709 articles that resulted from the initial search, 131 were selected for the study. Route length was the sole factor used to determine the best route in the majority of the studies. Routes with less obstacles, less turns, more landmarks and close to walls were selected by the other studies. User variations were considered in few studies. Unique needs of the BVI persons were addressed by few novel algorithms which had integrated multiple parameters and BVI-friendly route modelling. Differences between the navigation capabilities of the sighted and the BVI community were not a major concern when deciding the optimum routes in the majority of BVI indoor navigation tools. How to trade-off between factors affecting optimum routes, and how to model suitable routes in complex buildings needs to be studied further, looking from the user perspective. Navigation differences between sighted and blind and vision-impaired (BVI) communities are not concerned frequently when planning routes in indoor navigation tools of BVI persons. Selecting routes avoiding areas difficult to traverse, close to walls, having landmarks, and less turns are some approaches used to address the unique needs of the BVI community. Assisting for recovery from veering and real-time obstacle detouring are useful features offered by these tools. Identifying and prioritizing different factors contributing to better routes, concerning user variations, and adopting multi-objective route optimization will help to develop improved route planning methodologies for BVI indoor navigation tool [ABSTRACT FROM AUTHOR]