Talking signs: a remote signage, solution for the blind, visually impaired and reading disabled

A system of signage which can be read from a distance by a person who is blind is needed to provide a truly accessible environment. Such a system, the Talking Signs: is described here. Infrared transmitters are used to send sign conten ts to receivers ca r r i ed by blind travelers, who can receive the sign information in the form of speech. The need for such a system is discussed, along with its technology, history and progress to date. INTRODUCTION THE PROBLEM The ability to read signs at a distance in order to orient one's self and find places and routes is taken for granted by most people. Without signs, the world would be a mysterious and even frightening place, and certainly one in which wayfinding would be next to impossible outside an individual's familiar environment near home. Yet blind individuals are routinely faced with the problem of navigating without signs. Even the relatively few braille signs now present in certain areas have to be W before they can be read; they cannot be said to make the world accessible. For a person who is blind, an accessible phone booth is one that can be found, an accessible subway entrance is one that can be located, and an accessible bus or train is one that can be identified. The language of the Americans with Disabilities Act (ADA) requires that such public facilities be accessible to all. SOLUTION: REMOTE SIGNAGE SYSTEMS A signage system which is truly accessible to the blind, visually impaired, and reading disabled must incorporate the ability to find and read signs from a distance; in other words the property of remote signage. Such a system is the Talking Signs,R first developed in our laboratories in 1979 [ I ] and since extensively evaluated and refined. The system uses infrared transmitters, placed at sign locations, transmitting digitized speech information. The blind traveler with a suitable receiver can scan the environment for signs when desired, determine the presence and direction of any signs that are present in the vicinity, and receive the spoken sign contents (eg., "restroom"). The transmitters are easily recordable in any language with any message, and have very modest power requirements. The system has been successfully evaluated in a number of laboratory studies [2,3.4,51 and in several limited indoor and outdoor installations. The laboratory studies confirmed the system's abiiity to facilitate the finding of rooms and other destinations in unfamiliar surroundings, and response from blind persons testing the system has been overwhelmingly positive. Installation costs are substantially lower than for the now ubiquitous wheelchair curb cuts and ramps. TECHNICAL CONSIDERATIONS 0-780313771/93 $3.00 01993 IEEE 1309 While any of several potential transmission media could provide remote signage in some form, infrared transmission as implemented by the present system has a number of advantages. The optical spectrum is still largely uncluttered, and the technology required is simple. Infrared LEDs at the 950 nanometer range are used for transmission wi th a frequency modulated 25 kHz subcarrier, either pulsed or sinusoidal. (While low duty cycle pulsed transmission increases effective range, sinusoidal drive reduces intermodulation products for multichannel applications requiring more than one subcarrier). Receiver circuits have been designed to give adequate performance under full sun conditions. Transmitters and receivers are now commercially available, as well as designs for home-built versions [ 6 ] . A major consideration is the optical and mechanical convenience of transmitter beamshaping so that any desired area can be covered while excluding adjoining regions. Similarly, receivers are easily made as directional or broadbeamed as desired, with no bipolar ambiguity as experienced in radio direction-finding below microwave frequencies. Clearly, convenient dmctionality is very important since the tindinn of the sign is a key objective. Powering of remotely accessible signs is simplified by the fact that many important print signs are located near a power source (street lamps, porch lamps, illuminated bus signs, phone booths, etc.). Solar power with battery backup is presently being designed. More advanced developments can readily be envisaged including multilanguage, multichannel systems with varying degrees of information selected by the user, and very low power systems. References [l] Loughborough, W. "Talking Lights," journal o/ Visua[ Impairment and Blindness, June 1979,243. [2] Signs," Journal of Visunl Impairment and Blindness, 1982, NO. 76,77'-78. [3] the Blind," Human Fuctors, 1983, Vol. 25, No. 1,49-53. Brabyn, J. and Brabyn, L. "Speech Intelligibility of the Tallung Brabyn, L. and Brabyn, J. "An Evaluation of Talking Signs for REAL-WORLD IMPLEMENTATION With the passage of the ADA, interest has revived in remote signage, reflecting a growing recognition that braille signs are only a part of the solution since, except in confined spaces such as elevators, such signs are difficult to find. Accordingly, large-scale model demonstrations of Talking SignsR are now i n the process of being planned and implemented. ln San Francisco, the "Accessible City" project is under way involving a number of public and private entities. After initial installation at a complex intersection (5th and Market Streets) by the Department of Parking and Traffic in San Francisco, installations are committed for the new public library, criticaI intersections in downtown San Francisco, and the new 5-acre Yerba Buena Center to open in 1993. Other plans being explored include transit systems and other facilities covering a "critical mass" of the downtown area. Together with other projects now under way, these installations will be on a large enough scale to provide a me I41 Loughborough, W. Talking Signs An Accessibilib Solution for the Blind and Visually Impaired," Proceedings, 12th C.M.B.E.C./lsl Pan Pocific Symposium, Vancouver, B.C., July 18-26,1986. [SI Schenkman, B. "The Effect of Receiver Beamwidth on the Detection Time of a Message from Talking Signs, A n Auditory Orientation Aid for the Blind," Inletnational ]ournaI of Rehabilitation RcscPrch, 1986,9(3), 239-246. 161 ThC Smith-Kettlmell Technical File, Vol. 12, No. 4,'Fall1991. Acknowlednments This research was supported by grants from the National Institute on Disability and Rehabilitation Research and The Smith-Kettlewell Eye "real world" proving ground. Research Institute. Figure 1. The Talking Signs' System