Dipole-Based Filtering for Improved Removal of Background Field Effects from 3D Phase Data

Samuel James Wharton¹, Richard Bowtell¹

A robust method for filtering 3D phase data dominated by rapidly spatially varying externally generated fields is presented. One or more dipole point sources situated outside of the region of interest are used to model and remove the unwanted background fields caused by remote tissue/air interfaces such as those that are present in the sinuses. The method was tested on simulated and experimentally acquired phase data and compared to other commonly used filtering methods, including Fourier filtering and polynomial fitting. The results show that the dipole-based filter outperformed the other methods in removing unwanted fields and preserving image contrast.