| 摘要 |
PROBLEM TO BE SOLVED: To provide an image reading apparatus capable of shortening the time required for acquiring reference data to be used for shading correction.SOLUTION: A shading correction part 40 of the image reading apparatus is configured to acquire image signals more than image signals that an inter-line correction part 60 can acquire per unit time, and comprises: an adder 411 for adding an image signal DA each time the image signal is acquired, to calculate a reference image signal DC that is added exponent times of 2; and a shared internal memory 42 of which each of two storage regions is used for holding the reference image signal DC and outputting an average reference image signal DD in such a mode that the reference image signal DC is bit-shifted to be an average value. When outputting the average reference image signal DD of the previous time from one of the storage regions of the shared internal memory 42, the reference image signal DC of the present time is held in the other storage region. The inter-line correction part 60 sets reference data for shading correction based on the average reference image signal DD.SELECTED DRAWING: Figure 7 |
