| 摘要 |
PURPOSE:To extract securely the features of even a low-contrast pattern by coding an input pattern signal into a binary signal on the basis of a high, a low, and an intermediate fixed slice levels, and storing the signal in a shift register selectively in series and processing it. CONSTITUTION:The input pattern signal is inputted to binary coding circuits 1-3 having the high, low, and intermediate slice levels and their output binary- coded signals XH, XL, and XM are inputted to a selecting circuit 4 and a control circuit 7 while the signal XM is inputted to the shift register SR6. The circuit 7 outputs selection signals S1 and S2 to the circuit 4 on the basis of the mutual relation among the signals XH, XL, and XM and also sends out a transfer control signal AB or BA to SRs 5 and 6 when specific condition is satisified. The circuit 4 selects one of the signals XH, XL, and XM according to the combination of the signals S1 and S2 and inputs the output signal P to the SR5. The SRs 5 and 6 are transferred each other parallel data according to the signals AB and BA, and the SR5 outputs the binary-coded signal (y) obtained by extracting the features of desired low contrast. |
