| 摘要 |
<p>PURPOSE:To perform stable reading by reading >=2 kind of bar codes differing in width, holding and coverting the peak value of each bit of the signal into a continuous signal, and adjusting the gain, amplifying the signal to a prescribed level, and shaping the signal into a rectangular wave. CONSTITUTION:A bar mark 3a on a card 3 moving as shown by an arrow is scanned on a line 3b and reflected light 1b of a light source 1 is read by plural image sensor 2a. By the clock sgnal of a clock signal generator 6, the output of the image sensor 2a is converted into a serial signal, which is sample and held at an analog amplification part 4 by the clock signal to perform AGC amplification; thus waveform conversion into a continuous signal is performed to obtain a logical signal. For example, white is at a level 1 and black is at a level 0. Then, wide/narrow discrimination is performed by a digital conversion part 5 to obtain a parallel digital signal, i.e. information codes of bar codes, and an arithmetic processing part 7 performs information processing. Consequently, the bar codes are read accurately even in case of variation in illuminance and a stain on the card surface.</p> |
