| 摘要 |
PROBLEM TO BE SOLVED: To accelerate reading speed without narrowing readable conditions and to surely read a two-dimensional(2D) code. SOLUTION: The gains 2 and 3 on better reading conditions and the gains 1 and 4 on worse reading conditions are set by a control circuit, an amplifier circuit is provided for amplifying an electric signal, for which optical information is transduced based on the respective gains set by the control circuit, and when a decoding part successfully decodes character data corresponding to the 2D gain by reading the 2D gain with the gains 2 and 3 on the better reading conditions, reading operation is finished. When the decoding part does not successfully decode the 2D code even by reading it (n) times with the gains 2 and 3 on the better reading conditions, the 2D code is read (n) times with the gains 2 and 3 on the better reading conditions and read with the gains 1 and 4 on the worse reading conditions later. |
