Patent ID: 7775434

Claim:
A bar-code reading apparatus, comprising: a differential processor which generates a differential signal from an electric signal corresponding to an intensity of light reflected from a bar code; an extreme value detector which detects an extreme value in the differential signal generated by the differential processor, and generates extreme value information including at least an electric signal value of the detected extreme value; a calculating unit configured to calculate, for each extreme value in the extreme value information, a difference value between the electric signal value of the extreme value and an electric value of at least one of extreme values adjacent to the extreme value; a determining unit which compares the difference value with a predetermined threshold value and determines a validity of the extreme value corresponding to the difference value, for each difference value calculated by the calculating unit; and a decoding processor which decodes information encoded as the bar code by using the extreme value information of the extreme value which is determined to be valid by the determining unit.