| 摘要 |
PROBLEM TO BE SOLVED: To properly perform an automatic density adjustment even when a document cover is opened so as to provide a good copy image by preparing a histogram from image data, correcting the image data, based on the histogram, and adjusting the density, based on the correction. SOLUTION: A histogram preparation circuit 80 prepares a histogram of density according to image data from a scanner part 1. Also a correction reference value calculation part 81 calculates a correction reference value, based on a histogram prepared in the histogram preparation circuit 80. In addition, a range correction circuit 82 corrects a density range using the correction reference value from the correction reference value calculation part 81 so as to automatically adjust the density at real time. Thus, because the histogram can be prepared by prescanning operation without performing data sampling from those parts other than documents, the density can be adjusted automatically by a proper correction reference value. |
