Method and apparatus for detecting document size

摘要

Disclosed is a method for detecting a document size when the width of a document to be scanned is smaller than an effective scan width of a scanner module. One block of a plate is scanned before a document to be scanned is fed and it is stored as a reference colour data value. After pre-scanning a first block of the document, it is successively compared and judged whether a colour data value corresponding to a first slice is the same as the reference colour data value. In the case that the colour data value of an optional slice is the same as the reference colour data value, the size corresponding to the position of a slice just before the optional slice is detected as the size of the document. <IMAGE>