| 摘要 |
PURPOSE:To accurately detect infrared radiation sensitivity in each of a normal part and a flaw part, by correcting the variation in the infrared radiation sensitivity of a material to be inspected due to the variation in a heating time or a heating attenuation time when the feed speed of the material to be inspected varies. CONSTITUTION:When the feed speed of a material 2 to be inspected varies, the feed speed of the material 2 to be inspected is detected by a feed speed detector 7 to be inputted to a feed speed detection circuit 8 and corrected by a heating time correction circuit 9 and the variation in a heating attenuation time, when the material 2 to be inspected is fed between a heating apparatus 3 and an infrared ray detector 5 detecting the infrared radiation sensitivity of the material 2 to be inspected, is corrected by a heating attenuation time correction circuit 10. When feed speed variation quantity is positive, infrared radiation sensitivity correction quantity 14 is negatively outputted and, when negative, said correction quantity is positively outputted. A sensitivity correction circuit 11 is an adder for adding the output of the infrared detector 5 and that of the heating time correction circuit 9 and the output thereof is compared with a reference flaw judge level 13 by a signal processing circuit 6 to perform flaw judgement.
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