| 摘要 |
Bar with count values indicating widths of white and black bars, which are reciprocally obtained, are input to buffers connected in series at 16 stages. The bar width count values written to those buffers are sequentially shifted each time a new bar width count value is input. A comparing circuit compares the widths of the adjacent bars in the same color with each other and checks whether or not a ratio therebetween falls within a range of 0.2-5.0 times as large as each other. Results of the comparisons by this comparing circuit are written to result registers connected in series at 13 stages. The check-results written to those result registers are sequentially shifted each time a new bar width count value is input. Accordingly, if all the check results written to all the result registers indicate an "in-range" state, it follows that the fifteen or more bars consecutively meet a bar code condition. Hence, the counter lets an AND gate open. If even one of the check results written to the result registers indicates an "out-of-range" state, the counter starts counting. Then, when a count result reaches 17, the counter lets the AND gate close. Therefore, just when one of the check results written to the result registers is in the "out-of-range" state, the bar width count value written to each buffer is output. The bar width count values input thereafter are disposed of.
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