Traversal Window Inversion of 3-D Boundary of Micro Magnetic Target Based on Quantum Imaging Technique

The 3-D boundary identification of magnetic targets is of significant importance for the magnetic characteristics assessment of magnetic devices. A high-fidelity reconstruction method for the 3-D boundary of tiny-sized magnetic targets through inversion techniques is presented in this article. Based on nitrogen-vacancy (NV) color centers in diamond, vector magnetic imaging with high sensitivity, wide field of view, and alignment-free is realized. Based on the anomaly distribution of the total magnetic field intensity (TMI), we determined the spatial dimensions and depth for the inversion and discretized the 3-D space into a grid. In order to overcome magnetic field noise and overlapping interference, we proposed a multiwindow inversion model by constructing inversion windows of various sizes. The application of various window sizes for inversion, along with the utilization of their corresponding gradient weights in a weighted combination, effectively addresses the ill-conditioned inversion challenges stemming from the nonlinear crosstalk of magnetic field noise. The experimental results show that the proposed method can achieve an inversion accuracy of 99.1% with a sensitivity of <inline-formula> <tex-math notation="LaTeX">$2~\mu $ </tex-math></inline-formula>T/<inline-formula> <tex-math notation="LaTeX">$\surd $ </tex-math></inline-formula>Hz. Compared with the method of L0–L2 norm regularization inversion, the inversion accuracy is improved by 3.5%. This method opens up a way for high-fidelity 3-D magnetic target boundary inversion.