Wearable assistive devices for visually impaired: A state of the art survey

Recent statistics of the World Health Organization (WHO), published in October 2017, estimate that more than 253 million people worldwide suffer from visual impairment (VI) with 36 million of blinds and 217 million people with low vision. In the last decade, there was a tremendous amount of work in developing wearable assistive devices dedicated to the visually impaired people, aiming at increasing the user cognition when navigating in known/unknown, indoor/outdoor environments, and designed to improve the VI quality of life. This paper presents a survey of wearable/assistive devices and provides a critical presentation of each system, while emphasizing related strengths and limitations. The paper is designed to inform the research community and the VI people about the capabilities of existing systems, the progress in assistive technologies and provide a glimpse in the possible short/medium term axes of research that can improve existing devices. The survey is based on various features and performance parameters, established with the help of the blind community that allows systems classification using both qualitative and quantitative measu.res of evaluation. This makes it possible to rank the analyzed systems based on their potential impact on the VI people life.