British Telecommunications Public Limited Company

British Telecommunications Corporation

Brian A Fenn

William John Welsh

Richard C Nicol

Roger J Clarke

Paul Challener

King N Ngan

Visual images of the face of a speaker are processed to extract during a learning sequence a still frame of the image and a set of typical mouth shapes. Encoding of a sequence to be transmitted, recorded etc. is then achieved by matching the changing mouth shapes to those of the set and generating codewords identifying them. Alternatively, the codewords may be generated to accompany real or synthetic speech using a look- up table relating speech parameters to codewords. In a receiver, the still frames and set of mouth shapes are stored and received codewords used to select successive mouth shapes to be incorporated in the still frame.

Image encoding and synthesis

A method and an apparatus for transmitting an image in which the image is sampled at a first plurality of points. The samples are then subjected to a two-dimensional unitary transform to produce a second plurality of transform coefficients, the second plurality being smaller than the first plurality and being obtained either by selection or truncation of the transform to provide the coefficients containing only the lower frequency components of the image. The transform coefficients are transmitted and on receipt converted by the inverse transform to a second plurality of image samples. Suitable transforms include the Hadamard and the discrete cosine. The image transmission is described as part of a viewdata system.

Method and process for transmitting an image

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Woodbridge, United Kingdom

Brian A Fenn