| 摘要 |
PROBLEM TO BE SOLVED: To reduce communication time and communication cost by enhancing a compression rate in the case of coding an image consisting of many black pixels with the JBIG system. SOLUTION: A high black rate part detection section 12 detects a line, where an existential probability of black pixels exceeds 50% in one line or a black pixel consecutive part over a percentage equivalent to 30% with respect to a total pixel number in one line as a high black rate part in image data to be sent. After reversing a black/white part of the detected high black rate part by a black/white reverse section 13, a coding/decoding section 6 applies JBIG coding to the image. Furthermore, the coding/decoding section 6 describes the position of the high black rate part in a comment marker segment. When the image data processed are received in this way, the black/white inverting section 13 applies black/white inversion to the part of the described position in the comment marker segment in the image data decoded by the JBIG system.
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