| 摘要 |
<p>PURPOSE:To eliminate the setting of gain and shorten the reading time for an optical character reading device incorporating a threshold circuit, by changing the threshold circuit into the binary signals based on the overall mean signal. CONSTITUTION:The texture analog signals 16 and 17 read by optical reading elements 4 and 5 are supplied to mean value arithmetic circuits 13 and 14 to obtain mean signal levels AV1 and AV2 each. These levels are supplied to a main scan mean value arithmetic circuit 15 to obtain a main scan mean value level signal AVT. The signal AVT is supplied to gain controllers 8 and 9 to give an integrated control to each gain and also supplied to threshold circuits 11 and 12 to be changed into the white or black binary signals. In such way, both a gain control and a decision of threshold are carried out simultaneously. This eliminates an individual setting of gain for the gain controllers.</p> |
