Method of and device for reading optical data code

摘要

A two-dimensional code reader repeats a cycle of ordinary code-reading processes such as taking an image of an optical data code, extracting a two-dimensional code from the image and decoding optical data of the two-dimensional code in the image. A specified evaluation value for the optical data code is obtained from the results of processes carried out prior to the decoding step and stored if the decoding is done successfully. Data which show the changes in the evaluation value with time are displayed. The evaluation value may be compared with a specified warning level and a warning output is made, depending on the result of the comparison.