INDUCTION HEATING FLAW DETECTOR

PURPOSE:To obtain an induction heating flaw detector which enables the prevention of erroneous detection in a surface flaw detection of a bar-like material to be inspected even when a part with a lover infrared emissivity and a pin angle exists on a surface. CONSTITUTION:This apparatus is provided with an infrared camera 5 which takes infrared rays 4 to be radiated from the surface of a material 1 to be inspected heated by electromagnetic induction to obtain an image data and a video interface 6 and an image memory 7. Moreover, a normal-way differentiating part 8 and an opposite- way differentiating part 9 are arranged to perform a differentiation processing of a width-wise image date of the material 1 to be inspected from two directions while a synthesizing section 10 is provided to perform an AND processing of a bidirectional data obtained. A flaw judging section 11 is provided to judge flaws by the resulting synthetic data and a judgment level setting section 12 to set a judgment level. On the other hands, as a measure for erroneous detection because of a pin angle, a flaw histogram preparing section 13 is provided which totalizes a flaw judgment data for the overall length to obtain a flaw value distribution data per width position. Thus, a width-wise flaw judgment level is changed based on the flaw value distribution data to accomplish a rejudgment processing.