DETECTING AN ANOMALY IN AN OBJECT OF ELECTRICALLY CONDUCTIVEMATERIAL

摘要

Detecting the presence of an anomaly (7) in or near an object (3) using a probe (1) comprises: a) selecting a set of points on the near surface (5) which are to be inspected, and selecting a first direction (18) and a second direction (20); b) selecting a first inspection point from the set; c) positioning the probe (1) at the selected inspection point in the first direction (18), inducing eddy currents in the object and determining a characteristic value of the electromagnetic field; d) positioning the probe (1) in the second direction (20) at the selected inspection point, inducing eddy currents in the object and determining a characteristic value of the electromagnetic field; e) selecting a next inspection point from the set and repeating steps c) and d) until all inspection points have had their turn; andf) inferring that an anomaly (7) is present at an inspection point (15) i f a combination of the characteristic values in the first and second direction deviates significantly from a norm.