IMAGE READING APPARATUS AND IMAGE READING METHOD

摘要

Provided is an image reading apparatus configured to recognize edge portions of an image of an original precisely without being influenced by the varying state of the four sides of the original. The image reading apparatus includes an image reading unit configured to read the original image by scanning the original, an edge determining unit configured to determine first edge locations at the left end and right end of the original image in a main scanning direction, an edge detector configured to detect a second edge location of the original image in a sub-scanning direction, a tilt expression calculator configured to calculate a linear expression that represents the amount of inclination of the original image with respect to the main scanning direction.

主权项

1. An image reading apparatus, comprising:
an image reading unit configured to read an image of an original by scanning the original; an edge determining unit configured to determine first edge locations at a left end and right end of the original image in a main scanning direction, based on edge portions of the original image that are detected along a plurality of lines in the main scanning direction of an image read by the image reading unit; an edge detector configured to detect a second edge location of the original image in a sub-scanning direction; a tilt expression calculator configured to calculate a linear expression that represents an amount of inclination of the original image with respect to the main scanning direction, based on the second edge location within a given range that comprises a midpoint between the first edge location at the left end and the first edge location at the right end; a reference point calculator configured to calculate a reference point that serves as a reference for inclination correction, by using the first edge locations and the linear expression; and an inclination corrector configured to correct the inclination of the original image based on the reference point and on the inclination amount.