| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an image data encoder capable of further enhancing compression rate for such an image that comparatively many boundaries ("edge areas" hereafer) between a white solid and a black solid area exist, especially such as a character image. <P>SOLUTION: In the case of performing JBIG (joint bilevel image experts group) compression respectively by dividing the image into tone characteristic data,ψ0 data andψ1 data after performing BTC (block trancation coding) compression, when a block to be processed is the white solid area (S202: Yes), a value of quantization data is converted into a value taken by a white area when the edge area is encoded (S203) and when the block to be processed is the black solid area (S204: Yes), the value of the quantization data is converted into a value taken by a black area when the edge area is encoded (S205). <P>COPYRIGHT: (C)2004,JPO</p> |
