| 摘要 |
PROBLEM TO BE SOLVED: To provide a binary threshold setting method and device by which an appropriate binary threshold corresponding to pixel density of a background of an original is set. SOLUTION: The binary threshold of a noticing pixel is calculated by selecting the optional number of pixels from a predetermined area centering around the noticing pixel and comparing the pixel density of the selected pixels with a setting threshold Th set by a user. The number of pixels cnt1 of pixels whose pixel density is more than the setting threshold Th, its average pixel density Ave1, the number of pixels cnt2 of pixels whose pixel density is less than the setting threshold Th and its average pixel density Ave2 are calculated, when the number of pixels cnt1≤a predetermined value B or the number of pixels cnt2≤the predetermined value B, the setting threshold Th is considered as the binary threshold and when the number of pixels cnt1>the predetermine value B and the number of pixels cnt2>the predetermined value B and (Ave1-Ave2)≥a differential threshold A, (Ave1+Ave2) is considered as the binary threshold and when (Ave1-Ave2)<the differential threshold A, the setting threshold Th is considered as the binary threshold. COPYRIGHT: (C)2007,JPO&INPIT
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