Image reading apparatus that aligns directions of document images, image reading method, image forming apparatus, and recording medium

An image reading method for reading images on a plurality of documents to create image data, the image reading method comprising:

• recognizing characters in at least one of a plurality of directions, the characters being expressed by the created image data;
• calculating incorrect recognition indexes, the incorrect recognition index being set based on a count of incorrect recognition characters, the count of incorrect recognition characters being a count of candidates for characters possibly incorrectly recognized when the plurality of documents are read, the incorrect recognition index being set such that recognition certainty indicative of accuracy of the recognition becomes smaller as the count of incorrect recognition characters increases;
• adjusting the recognition certainty using the incorrect recognition index;
• determining a direction of the plurality of documents based on the adjusted recognition certainty;
• and
• correcting the image data based on the determined document direction to align image directions of the plurality of documents;
• wherein the adjusting of the recognition certainty comprises dividing the recognition certainty by the incorrect recognition index for the adjustment.

A non-transitory computer-readable recording medium that stores an image reading program for controlling an image reading apparatus for reading images on a plurality of documents to create image data, the image reading program causing the image reading apparatus to function as:

• a character recognition processing unit that recognizes characters in at least one of a plurality of directions, the characters being expressed by the created image data;
• an incorrect recognition index calculator that calculates incorrect recognition indexes, the incorrect recognition index being set based on a count of incorrect recognition characters, the count of incorrect recognition characters being a count of candidates for characters possibly incorrectly recognized when the plurality of documents are read, the incorrect recognition index being set such that recognition certainty indicative of accuracy of the recognition becomes smaller as the count of incorrect recognition characters increases;
• a certainty calculator that adjusts the recognition certainty using the incorrect recognition index;
• a direction determining unit that determines a direction of the plurality of documents based on the adjusted recognition certainty;
• and
• an image processing unit that corrects the image data based on the determined document direction to align image directions of the plurality of documents;
• wherein the certainty calculator divides the recognition certainty by the incorrect recognition index for the adjustment.