Analysis and Implementation for a Walking Support System for Visually Impaired People

Introduction

Orientation, navigation and mobility are perhaps three of the most important aspects of human life. Significant features of information to aid navigation for active mobility are passed to human through the most complex sensory system, the vision system. This visual information forms the basis for navigational tasks; as such an individual with impaired vision is at a disadvantage because appropriate information about the environment is not available. The term blindness refers to people who have no sight at all as well as to those considered as blind have limited vision, which cannot be said to be severely visually impaired, (WHO, 1998). The major causes of blindness are age-related macular degeneration, cataracts, glaucoma, diabetic retinopathy, trachoma, onchocerciasis, by birth, lack of eye care and accident (Times of India, 2000). The development of assisting devices to aid visually impaired people in their everyday life has been increasing. In some cases, solutions to providing sensory supplementation such as Braille through electronic reading machines have been very effective. However, truly adequate solutions for navigation assistance for visually impaired have not yet been achieved. A number of devices have already been developed to address some of the difficulties faced by visually impaired people with regard to travel (Baldwin, 1998). This study therefore aims at examining the viability of different types of devices for mobility aid of blind; either using sensors or cameras, but some of them used both.

Visual impairment is one of the most common disabilities worldwide. WHO reported that due to the lack of epidemiological data, especially form the developing and under developed countries, the exact number of blind persons in the world is not known. In 1994, WHO estimated that it was around 38 million with a further 110 million cases of low vision, which are at risk of becoming blind? In 1998, the total population of visual impairment was more than 150 million people (WHO, 1998). Currently, there is a total of about 45 million blind people in the world and a further 135 million have low vision and this number is expected to double by 2020 (Times of India, 2000). The number of people who become blind each year is estimated to be 7 million. Over 70% of the people with vision problem receive treatment and their vision is restored. Thus the number of blind persons worldwide is estimated to increase by up to 2 million per year (WHO, 1997). Eight percent of these cases are ageing-related.

There are a quarter of a million people in the UK who are registered as visually impaired. However, in UK, actually there have nearly one million people entitled to register as a visually impaired person, and 1.7 million with the vision difficult. This represents over three percent of the UK population (NFB, 2002). In Britain, more than twenty thousand children grow up with visual impairment, and there are two hundred vision-related accidents per day in the UK alone (Leonard & Gordon, 1999; Viisola, 1995). There are approximately 10 million visually impaired people in the United States (AFB, 2001). In addition, statistics state that for every seven minutes, someone in America is becoming visually impaired (Blasch, 1999). In Malaysia, alarming increment in blind population is noted with about 46.9% from 1990 to 1999. By September 2000, there were about 13,835 registered in Blind Associations and it is predicted that, it might be less than 50% of the total blind population in the country (JKM, 2000).