Method and device for reading bar code

摘要

The present invention relates to a bar code reading method and a bar code reader applied preferably to POS systems used in the distribution industry. The object of the invention is to achieve an improved reading ratio or a reduced erroneous reading ratio in practical use by evaluating quantitatively the reliability of demodulation data and by performing a coincidence checking plural times only when a large error is recognized. When a reading distortion amount measured is within a predetermined allowable value, data extracted and demodulated from the bar code is judged to be valid, whereby the bar code reading is completed. When a reading distortion amount measured is not within the predetermined allowable value, if the same data from the bar code is extracted and demodulated continuously and at least twice, the same data extracted and demodulated from the bar code is judged to be valid, whereby the bar code reading is completed.