1. An image reading apparatus comprising: a reading section for reading images recorded on sheets; and a controller capable of performing operations of: extracting a plurality of patterns from the images read using said reading section; extracting the combination information regarding the combination of a plurality of the patterns from the images read using said reading section, judging whether the combination of the extracted a plurality of patterns coincides with the combination designated using the extracted combination information; and carrying out predetermined processing according to the result of the judgment.