| 摘要 |
PURPOSE:To improve efficiency, by subjecting the upper bit plane of a strong correlation between adjacent picture elements to run length coding after the forecast processing and by dividing the lower bit plane of a weak correlation into blocks by a unit of plural picture elements to code every block. CONSTITUTION:The upper bit plane is subjected to the forecast processing by forecasting circuit 4 before coded by run length coding circuit 6 because of a strong correlation between adjacent picture elements. The lower bit plane of a weak correlation between adjacent picture elements is subjected to block coding; that is, in case that the original picture is divided into blocks by the unit of four picture elements, block code ''11'' and two bits as the code indicating original picture patterns, namely, four bits are given for original picture patterns ''0101'', ''1010'', ''0011'' and ''1100'', and only the two-bit block code is given for other original picture patterns. |
