Image reading apparatus comprising correction of an image by using a converted time-series component converted from a frequency component extracted from a read pattern that is outside of a region in which an original is placed

An image reading apparatus comprising:

• a transparent member on which an original is placed;
• reading means configured to read an image of the original by scanning the original placed on said transparent member while moving the original in a first direction;
• a pattern provided in a position in which said reading means is capable of reading an image thereof in a second direction crossing the first direction and outside a region in which the original is placed;
• and
• a processor configured to:
• extract a frequency component in the image of said pattern read by said reading means in a period in which said reading means reads the image of the original placed on said transparent member while moving in the first direction;
• calculate a frequency component from the extracted frequency component in another position different from said position, in which said pattern is provided, with respect to the second direction;
• convert the calculated frequency component in said another position into a time-series component;
• and
• correct an image corresponding to said another position by using the converted time-series component in said another position.