| 摘要 |
<p>1517869 Image encoding apparatus INTERNATIONAL BUSINESS MACHINES CORP 20 Dec 1976 53034/76 Heading H4P Data in the form of a stream of bits representing picture elements (pels), derived from the raster scanning of a document 1, is stored in compressed form in a store 8 which can be accessed so that the data pertaining to the stored document can be transmitted to a receiver 13 or can be expanded in a decompressor 9 for plotting or printing by a plotter 10 or for display on a display unit. The required compression is effected by passing the original bit stream through a pel stripper 3 where bits are removed to leave a processed bit pattern in which the bits represent predominantly single-pel-width strokes constituting either the outlines or the centre lines of characters. A segment follower 6 detects contiguous bits and produces a series of segments representing the tracked strokes. Each segment is coded in an encoder 7 into code words representing the shape of the segments and code words representing the end points of the segments, the segment bit thus produced being stored in the store 8. The stripping process is described with reference to Fig. 2 (not shown), whilst the constraints which determine whether a pel is or is not stripped from the original bit stream are described with reference to Figs. 5 and 6 (not shown). Suitable arrangements for the units 3, 6 and 7 are described with reference to Figs. 7 to 13 (not shown).</p> |
