抄録
In biomagnetic measurement in a magnetically moderately shielded room, the dominant environmental field noise is the line-frequency (50 Hz) noise. We have studied off-line processing to reduce the line-frquency noise that is included in the raw data measured with a multichannel SQUID magnetometer. Our method utilizes digital filtering and averaging to obtain exclusively the magnetic field unit vectors, which represent the spatial distribution of the noise field. The results for the magnetic field waveform, after subtraction of line-frequency noise components, indicated the effectiveness of our method in reducing the noise. Further, localization of a single equivalent current dipole in a simulation showed that the noise-reduced data decreased the error of the dipole location and increased the goodness-of-fit values.
