Non-Invasive Imaging Using an Array of Electric Potential Sensors

Gebrial, W, Prance, R J, Harland, C J and Clark, T D (2006) Non-Invasive Imaging Using an Array of Electric Potential Sensors. Review of Scientific Instruments, 77. 063708-1. ISSN 0034-6748

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We present a design for a linear array of eight electric potential sensors arranged with 1 mm spacing and configured to measure spatially varying potential at the microscopic scale. The array successfully detects a 50 µm wide feature associated with one of the samples tested. In a single sensor arrangement we have demonstrated <1 µm resolution, but the data acquisition times can become prohibitive. The sensors operate noninvasively by capacitively coupling to the sample. The issues associated with using an array of sensors in close proximity are addressed. Cross coupling and strategies for matching the response of the sensors are described in detail. Results are presented for a range of samples including a resistive potential divider, a ceramic microwave circuit board, and a section taken from an oil drill pipe containing a known fault. The data acquisition times are compared with those of a single sensor system, with improvements of 4.5 times in speed reported. In one case real-time simultaneous data acquisition is demonstrated using all eight sensors. Since these sensors operate via the displacement current they may also be applied to the characterization of material properties, including, for example, insulators, dielectrics, and poorly conducting composite materials. It is concluded that we see significant improvements in the data acquisition times for the linear array over a single sensor as expected and are able to overcome the difficulties associated with operating an array of sensors in close proximity.

Item Type: Article
Additional Information: Experimental work by RA and myself, funded as part of EPSRC Basic Technology project (GR/R87550/01). Addresses integrating electric field sensors into an array format for real time imaging applications. Reports the successful results of using a combination of a hardware calibration routine and software compensation to match the response of eight sensors arranged as a linear array, achieving seamless data acquisition. As a result, Kodak European Research invited me to present this work and supplied a letter of support for the EPSRC translation grant (EP/E042864/1). They have subsequently funded a 3 year studentship on sensor development (Dr. C. Moore,
Schools and Departments: School of Engineering and Informatics > Engineering and Design
Depositing User: Robert Prance
Date Deposited: 06 Feb 2012 20:47
Last Modified: 02 Apr 2012 14:14
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