Patent ID: 7007847
Filing Date: 2006-03-07
Classification: G06K

Abstract:
1. A bar-code reader that scans a bar code that is formed by black bars and white bars each having a width that is an integral multiple of a basic width, comprising: a differential processing unit that calculates differential of a signal obtained by optically scanning the bar code to thereby obtain a differential data; a peak detector that detects peaks in the differential data; a peak-to-peak distance calculating unit that calculates peak-to-peak distances for all the peaks detected, the peak-to-peak distance being a distance between two adjacent peaks; a frequency-mapping unit that calculates, for each of the peak-to-peak distances, candidate values for the basic width by dividing the corresponding one of the peak-to-peak distance by each of a plurality of integral numbers that are possible candidates for the integral numbers respectively; a transition-route forming unit that selects, based on a predetermined criteria, a candidate value for the basic width corresponding to each of the peak-to-peak distances to thereby form a combination pattern for each candidate values of the basic width; and an error judging unit that judges an mount of error in each of the combination patterns, and determines a combination pattern, as a candidate combination pattern, having least amount of error from among the combination patterns; a basic-width determining unit that calculates the basic width from the candidate values for the basic width in the candidate combination pattern.