| 摘要 |
PROBLEM TO BE SOLVED: To provide a barcode reader capable of preventing the misdetection of a background even when the reflection factor of the background is high and accurately detecting an object to be detected to which a barcode is attached. SOLUTION: At the time of detecting operation of the object to be detected, a laser diode is turned on to generate pulses and a galvanomirror is stopped. After detecting the object, the laser diode is continuously turned on and the galvanomirror is driven. While reducing the gain of a variable gain amplifier part 2 from the maximum gain in each step in the absent state of the object, whether a background can be detected or not is judged on the basis of an output signal from the amplifier part 2 and the gain of the amplifier part 2 is set up to gain lower than the maximum gain in which the background is not detected by the prescribed number of steps. |
