Planar system for magnetic induction conductivity measurement using a sensor matrix
- 1 February 2004
- journal article
- Published by IOP Publishing in Physiological Measurement
- Vol. 25 (1), 403-411
- https://doi.org/10.1088/0967-3334/25/1/043
Abstract
In this study the performance of an axial gradiometer sensor for magnetic induction tomography was investigated and the results of measurements to determine the precision and sensitivity of the sensor were undertaken. In the first part of the study a single gradiometer sensor was used and the noise and drift were measured for two excitation current values at a single frequency of 600 kHz. The variations of the real and imaginary received signal components with conductivity were then obtained for samples with 0-5 S m(-1). Both sets of measurements were repeated using two different forms of capacitive shielding. In the second part of the study the results of preliminary measurements obtained with a 2 x 2 planar matrix of axial gradiometers are given. The results of a simulation of a similar matrix using a commercial electromagnetic field calculation programme are also presented for comparison. For the sample utilized, the sensor output showed a linear variation with conductivity for the imaginary component of 0.033 mV S(-1) m using an excitation current of 316 mA at 600 kHz. No apparent correlation with conductivity for the real component was observed. The noise and drift of the imaginary component of the sensor output were 0.001 mV and 0.006 mV respectively, for the same excitation current. The results of the planar matrix measurements and simulations suggest that significant sensitivity is provided by using the measurement coils of the adjacent sensors. The measurement results however suggest that large improvements in the sensor noise and drift performance are required for these data to be of use.Keywords
This publication has 8 references indexed in Scilit:
- Electrical conductivity imaging via contactless measurements: an experimental studyIEEE Transactions on Medical Imaging, 2003
- Magnetic induction tomography: phase versus vector-voltmeter measurement techniquesPhysiological Measurement, 2003
- CAPACITIVE EFFECTS AND SHIELDING IN MAGNETIC INDUCTION CONDUCTIVITY MEASUREMENTBiomedizinische Technik/Biomedical Engineering, 2003
- Magnetic induction tomographyMeasurement Science and Technology, 2001
- Magnetic induction tomography: hardware for multi-frequency measurements in biological tissuesPhysiological Measurement, 2001
- Contactless impedance measurement by magnetic induction - a possible method for investigation of brain impedancePhysiological Measurement, 1993
- 3D eddy current computation in the frequency domain regarding the displacement currentIEEE Transactions on Magnetics, 1992
- Electrodeless Measurements of the Effective Resistivity of the Human Torso and Head by Magnetic InductionIEEE Transactions on Biomedical Engineering, 1968