Real-time estimation of space magnetic field for magnetocardiographic devices

Active magnetic field compensation technology, as a crucial method for suppressing environmental magnetic disturbances and enhancing the signal-to-noise ratio (SNR) during magnetocardiography (MCG) measurements, requires accurate acquisition of disturbance magnetic field information in the target area for control decisions. This work assumes that within the vicinity of the magnetically shielded region, the magnetic disturbances are contributed by uniform current densities and proposes a spatial magnetic field estimation method based on the expansion of the magnetic scalar potential function (SMFE-PFE). Experiments on an MCG prototype demonstrated that SMFE-PFE effectively reduces estimation errors compared to the sensor-distance-normalized weighted spatial magnetic field estimation method (SMFE-Mean), with an average accuracy improvement of 12% across 24 verification points, particularly evident near the measurement sensors. The proposed method enables real-time and precise estimation of spatial magnetic field disturbances within the magnetically shielded region under low computational power conditions, providing necessary technical support for active magnetic field compensation.