Patent ID: 6819409
Filing Date: 2004-11-16
Classification: G06K

Abstract:
A reading arrangement comprising at least one detector arrangement arranged over a strip-shaped reading region in a reading plane and behind an optical imaging element, at least one lighting device arranged above the reading plane for completely illuminating the reading region from at least a first lighting direction and an evaluation unit for machine reading of a strip-shaped information strip with information optically encoded as a bit sequence which is disposed in the reading region of the reading plane, wherein a plane of symmetry is oriented parallel to an optical axis of the imaging element and intersects the imaging element, the detector arrangement comprising an at least one-line linear arrangement of photodetectors and the reading region centrally in the longitudinal direction, whereinthe optical imaging element serves to produce an image of the entire reading region on photosensitive faces, which are oriented parallel to the reading plane, of photodetectors of the detector arrangement, the evaluation unit has a reading cycle with at least two reading phases, in the reading phases, the lighting in the reading region differs in the lighting direction and/or the quality of the light emitted by the lighting device, the evaluation unit is adapted at least to receive and evaluate first detector signals of the photodetectors in the first reading phase and to receive and evaluate second detector signals of the photodetectors in the second reading phase in order to form a first and second sequence from the first detector signals and the second detector signals and, by inversion of the second sequence and comparing it with the first sequence the read-out information is checked for correct reading-off and authenticity, to obtain a verified bit sequence, and the evaluation unit is adapted to detect an element of the first and second sequence, respectively, out of the detector signals of at least three photodetectors arranged in a line in mutually juxtaposed relationship.