Document reading apparatus for correcting data of read image

A document reading apparatus, comprising:

• a tray on which a document is placed;
• a reading unit configured to read an image of the document;
• a reference member;
• a control unit configured to determine one reading mode among a plurality of reading modes based on input of an instruction for starting reading, cause the reading unit to read the image of the document placed on the tray in accordance with the one reading mode while conveying the document, and correct data of the image of the document read by the reading unit based on correction data for the one reading mode;
• and
• a setting unit configured to set a plurality of candidate reading modes selected from the plurality of reading modes as candidates for the one reading mode,
• wherein the control unit is configured to start generation processing for generating correction data for each of the plurality of candidate reading modes when the setting unit sets the plurality of candidate reading modes.