A New Halftone Reproduction and Transmission Method Using Standard Black and White Facsimile Code

This paper proposes an adaptive dithering method, which can reproduce grey levels with good character quality. It also proposes dither threshold patterns with long run-length, which are able to obtain a compression ratio of about 3 or 4 when using modified Huffman coding schemes. The method presented here is applicable to facsimile equipment for transmitting pictures, including both continuoustone pictures and characters, using CCITT standard black and white picture coding.