Image coding for level 3 Teletext and Videotext

摘要

Level 3 of the display specification of Teletext and Videotexincludes the provision of dynamically redefinable character sets whichcan be used to construct new characters or arbitrary graphic images. Theauthors describe how character recognition and clustering algorithms canbe used to map from a pixel-based image to the level-threecharacter-oriented Teletext/Videotex display format. The mappingtypically requires a compromise to be made between image codingefficiency, image accuracy, and aesthetic factors and would require aninteractive system where the image originator retains aesthetic controlwhile varying the character recognition and clustering parameters. Anoverview of image analysis for level-three Teletext is given. Patternmatching using standard character sets is described