Sensors 2016, 16(8), 1158; https://doi.org/10.3390/s16081158
System Description and First Application of an FPGA-Based Simultaneous Multi-Frequency Electrical Impedance Tomography
Philips Chair for Medical Information Technology, RWTH Aachen University, Pauwelsstrasse 20, Aachen 52074, Germany
*
Author to whom correspondence should be addressed.
Academic Editor: Nicole Jaffrezic-Renault
Received: 23 February 2016 / Revised: 2 June 2016 / Accepted: 21 July 2016 / Published: 25 July 2016
(This article belongs to the Special Issue Noninvasive Biomedical Sensors)
Abstract
A new prototype of a multi-frequency electrical impedance tomography system is presented. The system uses a field-programmable gate array as a main controller and is configured to measure at different frequencies simultaneously through a composite waveform. Both real and imaginary components of the data are computed for each frequency and sent to the personal computer over an ethernet connection, where both time-difference imaging and frequency-difference imaging are reconstructed and visualized. The system has been tested for both time-difference and frequency-difference imaging for diverse sets of frequency pairs in a resistive/capacitive test unit and in self-experiments. To our knowledge, this is the first work that shows preliminary frequency-difference images of in-vivo experiments. Results of time-difference imaging were compared with simulation results and shown that the new prototype performs well at all frequencies in the tested range of 60 kHz–960 kHz. For frequency-difference images, further development of algorithms and an improved normalization process is required to correctly reconstruct and interpreted the resulting images. View Full-TextKeywords:
electrical impedance tomography; multi-frequency; time-difference imaging; frequency-difference imaging; complex impedance; FPGA; bioimpedance spectroscopy
▼
Figures
Figure 1
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).
Share & Cite This Article
MDPI and ACS Style
Aguiar Santos, S.; Robens, A.; Boehm, A.; Leonhardt, S.; Teichmann, D. System Description and First Application of an FPGA-Based Simultaneous Multi-Frequency Electrical Impedance Tomography. Sensors 2016, 16, 1158.
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.