Method and apparatus for visual telecommunications, in particular for use by the deaf

摘要

In a system for visual telecommunications, e.g. for use by deaf people, an electronic camera (20) makes an image of a moving subject for transmission. The TV type image is passed through a contour extractor (25) to be converted to an animated cartoon line-drawing type image. The contour image is then compressed by means including a sampler (28) for image reduction, a difference detector (30) for selecting only points which change from one image to the next, a filter (34) for rejecting isolated points in the contour image, and an encoder (36) for converting sequences of on/off bits into data words for transmission, via a modem (14) over a telephone line (15). At the other end of the line a similar transmitter/receiver system decodes the received words and reconstitutes the successive images for display on a screen (46). The resulting animated cartoon type of display is adequate for communication by sign language or by lip reading, and is capable of being sufficiently compressed to be transmitted over a normal telephone line.