Fig. 2

A synthetic model which consists three magnetized blocks. a A perspective view of the synthetic model which displays the all non-zero model elements. The induced magnetization of each block is 2 A/m, and the directions of the ambient geomagnetic field are assumed to be \({I}=50^{\circ }\) and \({D}=-7^{\circ }\). b The total field anomaly computed by this synthetic model which is contaminated by an uncorrelated Gaussian noise with zero mean and a standard deviation \(\sigma _0= 1.0\,\hbox {nT}\). c The histogram of the contaminated noise