| 摘要 |
A binary image processing apparatus is provided which is capable of clearly and stably performing binary encoding of an image signal having a level corresponding to the density of each inputted pixel even when the difference in density between characters and background is small. Such apparatus includes a first level discriminating device which has a first input terminal for receiving an image signal having a level corresponding to the density of a pixel of the image signal and a second input terminal for receiving a signal indicative of a discrimination level so as to discriminate the level of the image signal by the discrimination level into binary data. A differential device obtains a differential value of the image signal at the pixel and a second level discriminating device discriminates the level of the differential value by a predetermined discrimination level. In response to image signals in the vicinity of the pixel, a calculating device determines an average value of density levels in the vicinity of the pixel and a discrimination level changing device supplies the average value to the second input terminal of the first level discriminating device but retains the discrimination level inputted to the second input terminal of the first level discriminating device when the differential value exceeds and is not more than the predetermined discrimination level.
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