| 摘要 |
PROBLEM TO BE SOLVED: To provide an image reading mechanism in a scanner, which executes optical smooth processing to form a kind of a low-pass filter and can improve throughput for the overall image processing. SOLUTION: A manuscript 61 is pressed down with a scanner roller 21, and it is conveyed toward an arrow 62, while it is read by an image sensor 24 to the direction of the arrow 62. A shutter plate 11 is a transparent plate member, and has thickness d. By means of thickness d, the focal position of the image sensor 24 is shifted slightly from the manuscript. Thus, the manuscript is read with gradation by the image sensor 24, by shifting the focal position of the image sensor 24 from the manuscript, and optical smoothing processing is executed using this gradation. Even if sharpness processing is applied, grainy noise will not be emphasized. Grainy noise, left after binary processing, is made to decrease, and image processing time is reduced at the same time. COPYRIGHT: (C)2004,JPO
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