| 摘要 |
PURPOSE:To extract dot data from image data at an optional thinning-out rate with good reproducibility and to adjust the contrast. CONSTITUTION:When the dot data are extracted at a thinning-out rate k/n where (k) and (n) are natural numbers, an extraction point calculation part 4 finds extraction points which are positioned at distances of ((n/k)X1, 2, 3) longitudinally and laterally from a reference point and a dot data extraction part 5 extracts the dot data at the extraction points from the image data; when dot data at an extraction point is a white dot, it is confirmed whether or not there is a black dot at the periphery of the extraction point and when there is the black dot, a black dot supplementation part 6 extracts the dot data at the extraction point as a black dot. When the dot data at the extraction point is a white dot, on the other hand, confirming a range wherein the presence of a black dot at the periphery of the extraction point is confirmed and the constitution is so made that the contrast of the extracted data is adjusted. |
