摘要 |
A run length which is the length of a run representing continuous black pixels is calculated on the basis of binary image data, and an extending process is performed for the run using a target pixel as an object to generate an extended run. An extended run length representing the length of the extended run and a maximum run length representing the length of the longest run in the range of the extended run are calculated. If a difference between the extended run length and the maximum run length is smaller than a predetermined value, an image near the target pixel is determined as a character image. If the difference is equal to or larger than the predetermined value, the image is determined as a half-tone image. In this manner, accuracy in separation between the half-tone area and the character area in a document image can be improved.
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