Detection, localization and classification of multiple dipole-like magnetic sources using magnetic gradient tensor data

• The modified tilt angles were designed to discriminate approximate locations of magnetic sources.
• Number of dipoles was detected using a fixed threshold.
• The accurately horizontal locations of dipoles were obtained based on the NSS.
• Magnetic moments were estimated using the forward model and measured tensor data.

We have developed a method for automatic detection, localization and classification (DLC) of multiple dipole sources using magnetic gradient tensor data. First, we define modified tilt angles to estimate the approximate horizontal locations of the multiple dipole-like magnetic sources simultaneously and detect the number of magnetic sources using a fixed threshold. Secondly, based on the isotropy of the normalized source strength (NSS) response of a dipole, we obtain accurate horizontal locations of the dipoles. Then the vertical locations are calculated using magnitude magnetic transforms of magnetic gradient tensor data. Finally, we invert for the magnetic moments of the sources using the measured magnetic gradient tensor data and forward model. Synthetic and field data sets demonstrate effectiveness and practicality of the proposed method.