| 摘要 |
<p>In measuring image noise of an image reader, image data obtained as a result of reading a read region of a test chart having a constant density are analyzed by an image analyzing program of a computer, so that an anomalous portion of the image data is extracted and is judged whether the anomalous portion is noise, on the basis of a predetermined standard. Further, in measuring the resolution of an image reader, a test chart having white/black line pair patterns, which are formed at a pitch slightly different from the read pixel pitch of the image reader, is read over a region which is large enough to include a location where coincidence occurs between patterns and pixels. A necessary portion is cut out from the read image, and a gradation difference for each pixel of the read image over the entirety of the cut-out region is calculated in order to detect the maximum gradation difference. When the maximum gradation difference exceeds a value for defective/non-defective judgment, the image reader is judged to have passed a resolution test. <IMAGE></p> |
