| 摘要 |
PROBLEM TO BE SOLVED: To provide an image processor which automatically extracts characters from a document image having a character area having possibility of either of black character on a white ground or white characters on a black ground. SOLUTION: The value M5 of a shortest distance up to a white pixel is found for the whole black pixels in an image for a binarized original image M2 and an inverted image M3 respectively, a maximum distance value being the maximum value of the found shortest-distance values M5 by a distance converting means is found as to the respective black pixel connection areas, and either of the original image or the inverted image is selected based on one or two more of the found maximum distance values. Consequently, a black pixel connection area constituting a character has a larger maximum distance value than any other area. Namely, by utilizing the fact as the thickness is larger and the area is also larger, the cases of the black characters on a white ground and the white characters on a black ground can be judged.
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