Printed matter processing system, watermark-containing document printing device, watermark-containing document read device, printed matter processing method, information read device, and information read method

摘要

In a watermarked document printing apparatus, secret information is divided, error correction encoding is performed to each divided pieces of information, and the secret information is converted into a pattern image and embedded in paper. In a watermarked document reading apparatus, after extracting signals from the pattern image on the paper, a reading error is detected by decoding the error correction code for each divided pieces of information, and the portion where the reading error exists is read again. The scanning process is performed again only to the portion where the decoding cannot be performed due to the temporal malfunction of the scanner or the like. Therefore, the pattern image can efficiently be obtained.