2.1 Results: After denting, MFL measurements were made on both sides of the dented sample. The concave side, termed the ‘topside’ of the sample, was the easiest side to measure – a thin sheet of plastic is placed over the ‘hole’
after which the hall probe moves essentially on a flat plane. The convex side, termed the ‘bottomside’ was more difficult to measure since the sensor must follow the dent contour. The bottomside results are of greater practical interest, however, since this is the side accessed in a typical pipeline inspection scenario. A full set of measurements were taken for both topside and bottomside orientations. For the sake of brevity, however, in the present paper we will focus primarily on the bottomside results, since these are most industrially relevant. Finally,
in these bottomside measurements the sensor was fixed to always be parallel to the original plane of the sample
(rather than the dent profile) as it traveled over the dent.