Review of sensor-driven assistive device technologies for enhancing navigation for the visually impaired

Most of our daily activities hinge on our ability to perceive our surroundings, with our eyes serving as pivotal sensory receptors. Our brain processes the visual data captured by our eyes, crafting a three-dimensional representation of our environment that empowers us to navigate and execute tasks. However, individuals dealing with visual impairments experience either partial or complete absence of this visual perception. In the past, conditions like myopia and astigmatism also lacked effective treatments, yet advancements in science and technology have enabled the creation of corrective aids like eyeglasses or even minor surgical interventions for vision enhancement. Over the years, researchers have conducted extensive investigations to devise devices catering to the needs of the visually impaired. This manuscript focuses on diverse sensors applicable in navigation systems tailored for this demographic. The review delves into recent advancements in navigation tools designed for the visually impaired, encompassing sensors such as visual, proximity, and LiDAR sensors, among others. Sensors generate copious amounts of data, which undergo processing to simulate the surrounding environment. We underscore the unique capabilities of each sensor, as well as optimal combinations of sensors that yield superior results. The challenges associated with sensor utilization are also addressed, accompanied by potential strategies for overcoming them. Our survey reveals a prevalent trend in utilizing RGB-depth sensing cameras and ultrasonic sensors in tandem with other sensor types for navigation purposes. This study aims to furnish a comprehensive overview of contemporary progress within the realm of navigation aids for the visually impaired, ultimately aiding researchers in discerning the most suitable technological approaches based on specific applications.