Fig. 1. Schematic of the experimental principle. (a) Energy-level diagram of the NV center; (b) ODMR (black) and Lorentz-fitted curve (red) for one pixel; (c) NV symmetry axes and laboratory frame directions X, Y, and Z, defined in terms of diamond lattice vectors.

Fig. 2. Schematic diagram of the NV center quantum microscope experimental setup and imaging method. (a) Schematic diagram of the wide-field diamond NV center quantum microscope experimental setup; (b) schematic diagram of the ODMR scanning imaging method, where the camera’s shooting speed is synchronized with the microwave frequency sweep rate, meaning each image captured by the camera corresponds to the fluorescence image of the NV center at a microwave frequency point. By correlating the fluorescence intensity of all the images with the swept microwave frequency points, a complete ODMR spectrum is composed.

Fig. 3. Multidipole magnetic model and localization algorithm. (a) The multidipole model in the reference system. The coordinate system is defined by the symmetry axis of the NV centers from Fig. 1(c) and the laboratory frame directions X, Y, and Z. (b) Algorithm for estimating the positions of magnetic flux, where the stage in the yellow box corresponds to data import and preprocessing; the stage in the green box corresponds to rough estimates of the positions of B_max and B_min; the stage in the blue box corresponds to precise estimates of the positions of B_max and B_min.

Fig. 4. Position and temperature error. (a)–(c) Position and error of the X axis, Y axis, and Z axis at 10 test nodes; (d) temperature and error at 10 test nodes.

Fig. 5. Feedback of the position and temperature of micromagnets in complex environments.