Method for detecting an anomaly in an object of electrically conductive material along first and second direction at inspection points

摘要

Detecting the presence of an anomaly in or near an object using a probe comprises:a) selecting a set of points on the near surface which are to be inspected, and selecting a first direction and a second direction;b) selecting a first inspection point from the set;c) positioning the probe at the selected inspection point in the first direction, inducing eddy currents in the object and determining a characteristic value of the electromagnetic field;d) positioning the probe in the second direction 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 is present at an inspection point if a combination of the characteristic values in the first and second direction deviates significantly from a norm.