DEFECT DETECTION METHOD AND DEVICE THEREFOR

PROBLEM TO BE SOLVED: To provide a method and device for identifying the defect size of an inspection object from a signal outputted from a magnetometric sensor array. SOLUTION: A defect detection method uses a database 51 having thickness reduction rate information wherein the leakage flux amount in the parallel direction to the inspection object surface in the leakage flux leaking from the inspection object is correlated with the thickness reduction rate of the inspection object in each defect size, a magnetizing device 5 for magnetizing the inspection object, the first magnetometric sensor 13 for detecting the leakage flux amount parallel to the inspection object surface in the leakage flux leaking from the inspection object 3, and the second magnetometric sensor 15 for detecting the leakage flux amount in the vertical direction to the inspection object surface. The method has a defect size identification process for identifying the defect size based on a detection value from the second magnetometric sensor 15, and a thickness reduction rate identification step for identifying the thickness reduction rate on reference to the thickness reduction information in the database 51 based on the defect size identified in the defect size identification step and a detection value from the first magnetometric sensor 13. COPYRIGHT: (C)2007,JPO&INPIT