Modern Applied Science; Vol. 10, No. 4; 2016
ISSN 1913-1844 E-ISSN 1913-1852
Published by Canadian Center of Science and Education
150
Comparisons of Sensor Position for Electrical Capacitance Volume
Tomography (Ecvt)
Irfana Kabir Ahmad
1
, Muhammad Mukhlisin
2
& Hassan Basri
1
1
Department of Civil and Structural Engineering, Universiti Kebangsaan Malaysia, Bangi, Selangor, Malaysia
2
Department of Civil Engineering, Polytechnic Negeri Semarang, Indonesia
Correspondence: Irfana Kabir Ahmad
Department of Civil and Structural Engineering, Universiti Kebangsaan
Malaysia (UKM), Bangi, Selangor, Malaysia. E-mail: irfana@ukm.edu.my
Received: December 9, 2015 Accepted: December 18, 2015 Online Published: February 2, 2016
doi:10.5539/mas.v10n4p150 URL: http://dx.doi.org/10.5539/mas.v10n4p150
The research is financed by Strategic Action Plan 2011 UKM and Prototype Development Research Grant from
Ministry of Higher Education, Malaysia.
Abstract
Tomography is a technique used to produce true reconstructed images from signal data. This data projection is
measured capacitance by numerous sensors located on the surface of the object at different position. Sensitivity
matrix with three-dimensional variation, especially in axial (z-axiz) direction are required for imaging a
three-dimensional object to differentiate the depth along the sensor length so that the electrical field intensity can
be distributed equally all over the three dimension space. In ECVT, when a dielectric material is introduced into
the vessel, the variation in the electrical capacitance between all possible combinations of electrodes are
measured. These changes are caused by diference in the permittivity of that material. From these capacitance
measurements, an image based on the variation of the permittivity of the cross section contents can be obtained.
In this study a numerical model using combine COMSOL MULTIPHYSICS v3.5 and MATLAB 2008a for
imaging of an object was developed. Three different position of rectangular sensor: 1-sided sensor, 3-sided and
U-shape sensor was designed and analyzed. 1-sided sensor displayed comparatively more uniform in both radial
and axial direction in the comparisons of sensitivity distribution.
Keywords: ECVT, 3-D volume imaging, 3-D sensitivity matrix, 3-D sensor capacitance
1. Introduction
The development of industrial process tomography systems for measurement and control has been growth by the
complex nature of industrial processes (Xie et al., 1992). In particular, Electrical Capacitance Tomography (ECT)
systems have been the subject of recent research toward developing a safe, affordable, fast, and reliable
industrial imaging tool (Cao et al., 2009; Wang et al., 2010). ECT has developed successfully after reconstruction
of data into 3D from 2D, and currently 3D data reconstruction are able in the real time. This new method in the
existing ECT system which is able to reconstruct 3D data not just by combining the 2D data but has a volumetric
and real time namely ECVT have made capacitance tomography is the most promising technique for imaging
purpose in the industry today.
ECVT technology is based on developing nonlinear distributions of electric field lines to recreate a volume
image of different materials in the imaging domain (Plaskowski & Beck 1988; Warsito et al., 2007). ECVT
system are features like low profile and flexibility of capacitance sensors, increasing number of imaging frames
per second, and quite low cost have surged the tomography technology to the top of the list of industrial imaging
tools. The development of ECVT includes of sensor design, electronics hardware and image reconstructions. In
this study, the main focusing of the research is on the position of the sensor capacitance.
According to Wang et al. (2010), ECVT helps in other imaging technologies in term of real time 3D feature,
applicability to complex geometries, reduce cost and low profile sensors and this 3D sensor information will be
presented with different sensor formations, dimensions and positions. There are many research conducted on
sensor design (Yang, 2010; Yang & Liu, 1999) the usage of external and internal electrodes, the number and
length of electrode, various earthed screen, driven guard electrodes, the effect of temperature and pressure to the
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