Abstract: A document scanner comprises a first image sensor unit (32) and a second image sensor unit (30) and a scanning mechanism (70, 72, 76, 80) for causing relative movement between a document and the units so that the units scan the document in a scanning direction. The first unit (32) is situated ahead of the second unit (30) in the scanning direction and partially overlaps the second unit.

Abstract: A document scanner comprises first and second image sensor units (30,32), each having an array of electromagnetic radiation detectors (44) situated adjacent circuitry (42) for operating the detectors. A scanning mechanism (70,72,76,78,80) causes relative movement between the detectors and a document to cause the detectors to scan the document along a scanning direction. The array of detectors of the first unit (30) is situated ahead of the array of detectors of the second unit (32) in said scanning direction, the orientation of the detectors of the first unit with respect to their circuitry thus being the reverse of that of the detectors of the second unit, thereby to reduce the distance, in the scanning direction, between the two arrays.

Abstract: A document scanner comprises a first image sensor unit (30) and a second image sensor unit (32) and a scanning mechanism (70, 72, 76, 80) for causing relative movement between a document and the units so that the units scan the document in a scanning direction. The first unit (30) is situated ahead of the second unit (32) in the scanning direction and partially overlaps the second unit.

Abstract: A document scanning method comprises causing relative movement between a document and first and second imaging elements, such that each of a succession of scan lines of the document is exposed in turn to the imaging elements; generating first and second image data words representative of overlapping portions of each scan line; and concatenating at least a portion of the words to generate a third word representative of the scan line, the method being characterised by the steps of cross-correlating at least a portion of each of the words to identify a portion of the second word that is included in the first word; discarding a portion of at least one of words; concatenating the first word or remainder thereof with the second word or remainder thereof to form the third word; and, if necessary, compressing or expanding the third word by linear interpolation so as to obtain a word of a predetermined length.