FREE SCAN METHOD OF SHUTTLE TYPE SCANNER

A pre-scanning method for a shuttle scanning system is described. A document or a document carrier sheet is fed in a forward feeding direction into the shuttle scanning system. The leading end of the document or carrier sheet is scanned to determine the existence or otherwise of a recognition code. If a recognition code is detected, it is assumed that a carrier sheet is present, which is longer than the document itself. The carrier sheet is fed in a forward feeding direction through the shuttle scanning system to pre-scan the document at a relatively low resolution, then fed in a reverse feeding direction through the shuttle scanning system and lastly fed in the forward feeding direction through the shuttle scanning system to scan at least part of the document at a relatively high resolution. On the other hand, if no recognition code is detected, it is assumed that a bare document is present. The document is fed in a forward feeding direction through the shuttle scanning system to pre-scan the document at a relatively low resolution, discharged from the shuttle scanning system and then fed in the forward feeding direction through the shuttle scanning system to scan at least part of the document at a relatively high resolution.