Surface Geometry Reconstruction of Corrosion Defects of Ferromagnetic Materials Products by the Optimization by Linear Approximation

The paper describes a technique developed by the authors for reconstructing the shape and size of surface corrosion defects in products made of ferromagnetic materials based on measured components of the magnetic leakage field strength near the surface of the test object. The optimization problem of approximating the signal of a two-dimensional finite element model to the measured signal was solved by optimization using linear approximation with constraints. A method for approximating the defect shape using basis splines and a physical justification for choosing the reference points of spline interpolation are presented. The described technique was tested in a numerical experiment using a symmetrical defect and an arbitrary-shaped defect as an example.