PURPOSE: To improve the accuracy of detecting flaws by picking up the surface of a red-hot metal material irradiated with a visible light containing a given wavelength by means of a color camera and detecting the surface flaws according to the color separation signals withdrawn as a logical signal through a density analysis.
CONSTITUTION: A flaw detection circuit 11 detects crack-affiliated flaws recognized in red on the surface of the cogging slab with the irradiation of the visible light. When the input logical signal of the red R is 1 in the binary level while the input logical signal of green G and blue B are both 0, the circuit outputs the logical signal 1 to an interface circuit 14. When the input logical signals of red, green and blue are all 1, the circuit outputs the logical signal 1 to the interface signal circuit 14 as the surface flaws are recognized as black scab-affiliated flaws. In this manner, the flaw detection accuracy can be improved.
SENO KOUJI
TSUSHIMA YASUTERU
MIHARA TOSHIAKI
ISHIDA ISOSHIROU
