Fast and economic conversion of images to a tactile presentation for blind people.

A new procedure for the conversion of binary black and white images to a tactile presentation perceptible by the blind is described. Conventional procedures are very time-consuming and expensive and are not adapted to produce the required low editions of tactile displays, e.g., for schools for the blind or individual applications. The procedure recently developed allows the fast, economical conversion of even single drawings to a tactile display with high resolution. An account of the investigations and valuations of all possible physical procedures of optical-to-tactile conversion is given. The new procedure, based on a slightly modified Xerox copying process in a first step and gumming tactile material with the tone powder at the darkened regions in a second step, is described in detail. The device realised is presented. It allows the conversion of one page of a drawing to a tactile display with a resolution of 0.3 mm within 1 min. Various applications of the system and experiences with blind users are reported. The implement proved to meet most of the requirements of blind people. It is easy to handle and produces tactile drawings of excellent quality. As it is based on commercial subsystems it promises an economical production even at small series.