| 摘要 |
PROBLEM TO BE SOLVED: To provide an isolated area emphasis filter circuit that emphasizes and detects the defect or the foreign material in an object to be checked photographed and appearing as an isolated area, for example, and conducts image digital processing where the effect of high frequency components of the measured object itself is reduced and only the defect or the foreign material is selectively emphasized. SOLUTION: A substractor 3 calculates a difference between an input signal and a signal processed by a smoothing filter 2 to emphasize a high frequency component of a received image signal. On the other hand, a band pass filter 6 provides the output of a signal whose frequency band is limited to output a smaller value at an edge of a measured object and to output a larger value at a foreign material. The output of the subtractor 3 and the output of the band pass filter 6 are calculated by an arithmetic circuit 4 and a signal whose isolated area is emphasized is outputted. |
