| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a bar code reader and a bar code reading method, capable of accurately reading bar code symbols, even if external light is incident. <P>SOLUTION: This bar code reader 1 has a differential processing part 13 generating a differential signal from an electric signal corresponding to a reflected light intensity of the bar-code symbol; an extremum value detection part 14 detecting each extremum value of the differential signal generated by the differential processing part 13, and generating extremum value information at least, including an electrical signal value of each the detected extreme value; a voltage difference calculating part 16 calculating the voltage difference between the electrical signal value of the extremum value and the electrical signal value of at least adjacent one extremum value, in each the extremum value in the extremum value information; and an extremum value verifying part 18 comparing the voltage difference and a prescribed threshold in each of the voltage difference calculated in the voltage difference calculating part 16, to decide the effectiveness of the extremum value corresponding to the voltage difference. Information recorded in the bar code symbol B is decoded by using the extremum value information of the extremum value that is decided as being effective by the extremum value verifying part 18. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
