Review of machine vision-based electronic travel aids

Visual impaired people have navigation and mobility problems on roads. Up to now, many approaches have been proposed to help these people navigate around using different sensing techniques. This paper reviews several machine vision-based Electronic Travel Aids (ETAs) and compares them with those using other sensing techniques. The functionalities of machine vision-based ETAs are categorized from low-level image processing such as detection of the road regions and obstacles to high-level functionalities such as recognition of digital tags and texts. In addition, the characteristics of the ETA systems for blind people are discussed.