| 摘要 |
<p>PURPOSE:To reduce read errors, by providing an automatic threshold value generating circuit which outputs a discrimination value coincident with a two- out-of-five code consisting of five bars for discriminating whether bars are long or short. CONSTITUTION:When the leading edge part given to a bar code is detected by photoelectric detection parts 3 and 4, a solid-state scanner 5a is operated a specific time later to scans within barcode entry ranges 2a and 2c. Then, an A/D converter 7a discriminates on whether the scanning result is ''1'' or ''0''; when the result is ''1'', its frequency is counted by a counting circuit 8a and the counted value of logic ''1'' of five bars is stored in a storage circuit 12. When stored counted values and N1-N5 in decreasing order, the automatic threshold value generating circuit 13 outputs a value (N2+N3)/2 as th bar-length discrimination value and a bar-length discriminating circuit 9a discriminates the bar length from the output of the storage circuit 12 and this bar-length discrimination value.</p> |
