scholarly journals Modeling and Calibration of Electrical Capacitance Tomography Sensor for Medical Imaging

2018 ◽  
Vol 11 (3) ◽  
pp. 1471-1477 ◽  
Author(s):  
M. Ambika ◽  
S. Selva Kumar
Keyword(s):  
Imaging Techniques ◽  
Low Cost ◽  
Dielectric Medium ◽  
Capacitance Measurement ◽  
Electrical Capacitance Tomography ◽  
Electrical Capacitance ◽  
Cross Sectional ◽  
Capacitance Measurements ◽  
Electrode Capacitance ◽  
Capacitance Tomography

Electrical Capacitance Tomography (ECT) is an imaging technique which generates a cross-sectional image representing the internal permittivity distribution based on external capacitance measurements. It possesses the advantages of being non-radioactive, non-intrusive, non-invasive, high imaging speed and low cost over the conventional imaging techniques. Inter-electrode capacitance measurements are done by exciting electrodes placed around the non-conductive dielectric medium cylinder inside which, the material to be imaged is placed. This paper emphasizes on modelling and calibrating an electrical capacitance tomography sensor using ANSYS APDL with medium as air, water and extending the procedure for normal bone and cracked bone. ECT sensor is modelled by mounting 12 electrodes symmetrically outside the cylinder. The cylinder is made up of Polyvinyl Chloride (PVC) which is non-conductive dielectric medium while the electrodes are made up of Copper (Cu) which is conductive. The electrodes are excited in pairs and the potential distribution which is based on permittivity of the medium is analysed using ANSYS and the capacitance between the electrodes were calculated. The entire electrode modelling, calibration and capacitance measurement for the simulated bone model with and without crack is presented in this paper.

Speed Improvement in Electrical Capacitance Tomography Through a Multiple Excitation and Receiving Method

2011 ◽  
Author(s):  
Zhaoyan Fan ◽  
Robert X. Gao
Keyword(s):  
Excitation Pulse ◽  
Capacitance Measurement ◽  
Electrical Capacitance Tomography ◽  
Electrical Capacitance ◽  
Output Current ◽  
Wide Range ◽  
Traditional Mode ◽  
Electrode Capacitance ◽  
Measurement Channels ◽  
Capacitance Tomography

Electrical Capacitance Tomography (ECT) is a method to determine the material distribution within the interior of a closed object by measuring the capacitance values across externally mounted electrodes. Traditionally, an AC excitation pulse is applied to a pair of electrodes that form a capacitor during each measurement step, in order to determine the capacitance from the output current measured. This paper investigates how the speed of inter-electrode capacitance measurement can be improved by comparatively studying three methods that affect the way electrodes are excited and signals are received: 1) multiple-excitation-single-receiving, 2) single-excitation-multiple-receiving, and 3) multiple-excitation-multiple-receiving. A PSPICE circuit model was built to simulate the bandwidth and interference between the simultaneously sampled measurement channels. Simulations using ECT sensors with 8 and 12-electrodes have shown that measurement speed can be increased by up to 3 ∼ 30 times as compared to the traditional mode of capacitance measurement. Such new capability opens up new possibilities for ECT as an effective tool for online, real-time monitoring of a wide range of dynamical processes in the industry.

Dynamic water fill level measurement using a phantom-dependent adaptive electrical capacitance tomography (ECT) method

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Christoph Kandlbinder-Paret ◽  
Alice Fischerauer ◽  
Gerhard Fischerauer
Keyword(s):  
Pipe Wall ◽  
Electrical Capacitance Tomography ◽  
Electrical Capacitance ◽  
Capacitance Measurements ◽  
Level Measurement ◽  
Element Simulation ◽  
Fill Level ◽  
Capacitance Tomography ◽  
Low Permittivity ◽  
Adaptation Scheme

Abstract In electrical capacitance tomography (ECT), the resolution of the reconstructed permittivity distribution improves with the number of electrodes used whereas the number of capacitance measurements and the measurement time increases with the number of electrodes. To cope with this tradeoff, we present a phantom-dependent adaptation scheme in which coarse measurements are performed with terminal electrodes interconnected to form a synthetic electrode ring with fewer but larger electrodes. The concept was tested by observing the sloshing of water inside a pipe. We compare the reconstructed results based on eight synthetic electrodes, on 16 elementary electrodes, and on the adaptation scheme involving both the eight synthetic electrodes and some of the elementary capacitances. The reconstruction used the projected Landweber algorithm for capacitances determined by a finite-element simulation and for measured capacitances. The results contain artefacts attributed to the influence of the high permittivity of water compared to the low permittivity of the pipe wall. The adaptation scheme leads to nearly the same information as a full measurement of all 120 elementary capacitances but only requires the measurement of 30 % fewer capacitances. By detecting the fill level using a tomometric method, it can be determined within an uncertainty of 5 % FS.

Image Fusion of ECT/ERT for Oil-Gas-Water Three-Phase Flow

2011 ◽  
Vol 3 (2) ◽  
pp. 29-34 ◽  
Author(s):  
Lifeng Zhang
Keyword(s):  
Image Fusion ◽  
Electrical Capacitance Tomography ◽  
Phase Flow ◽  
Electrical Capacitance ◽  
Cross Sectional ◽  
Three Phase ◽  
Three Phase Flow ◽  
Capacitance Tomography ◽  
Oil Gas ◽  
Image Fusion Method

The tomographic imaging of process parameters for oil-gas-water three-phase flow can be obtained through different sensing modalities, such as electrical resistance tomography (ERT) and electrical capacitance tomography (ECT), both of which are sensitive to specific properties of the objects to be imaged. However, it is hard to discriminate oil, gas and water phases merely from reconstructed images of ERT or ECT. In this paper, the feasibility of image fusion based on ERT and ECT reconstructed images was investigated for oil-gas-water three-phase flow. Two cases were discussed and pixel-based image fusion method was presented. Simulation results showed that the cross-sectional reconstruction images of oil-gas-water three-phase flow can be obtained using the presented methods.

Electrical Capacitance Tomography Based Sorting Technique for Wasted Plastics

2015 ◽  
Author(s):  
Yusuke Hirose ◽  
Kazuaki Hata ◽  
Sapkota Achyut ◽  
Masahiro Takei
Keyword(s):  
Temperature Distribution ◽  
Relative Permittivity ◽  
Electrical Capacitance Tomography ◽  
Electrical Capacitance ◽  
Time Step ◽  
Cross Sectional ◽  
Sorting Technique ◽  
The Many ◽  
Capacitance Tomography ◽  
Temperature Equation

This study has launched a concept to measure real time two-dimensional temperature distribution non-invasively by a combination of electrical capacitance tomography (ECT) technique and a permittivity-temperature equation for plastic pellets. The concept has two steps which are the relative permittivity calculation from the measured capacitance among the many electrodes by ECT technique, and the temperature distribution calculation from the relative permittivity distribution by permittivity-temperature equation. ECT sensor with 12-electrode is designed to measure and visualize the cross sectional temperature distribution during polymethyl methacrylate (PMMA) pellets cooling process. The images of the normalized relative permittivity distribution are successfully reconstructed at every time step during the process. The images indicate that the normalized relative permittivity of PMMA pellets is decreased as the temperature is decreased.

Visualisation of Two-Phase Gas-Liquid Pipe Flows Using Electrical Capacitance Tomography

Volume 1 ◽  
2004 ◽  
Author(s):  
Andy Hunt ◽  
John Pendleton ◽  
Yves Ladam
Keyword(s):  
Velocity Distribution ◽  
Virtual Instrument ◽  
Gamma Ray ◽  
Electrical Capacitance Tomography ◽  
Electrical Capacitance ◽  
Flow Loop ◽  
Two Phase ◽  
Cross Sectional ◽  
Measure Concentration ◽  
Capacitance Tomography

Electrical Capacitance Tomography (ECT) has been used over a number of years to measure concentration distribution, and more recently velocity distribution, in two-phase flows. ECT is non-intrusive, and the reconstruction of the concentration and velocity distribution can be undertaken in real time and over an arbitrary number of zones in the flow cross-section. In this paper the concept of a ‘virtual instrument’ is introduced where zones of the image can be structured for comparison with other measurements. Numerical agreement with gamma-ray density measurements is shown to be excellent in slug and stratified flows. We present a series of measurements undertaken in complex oil/gas slug flows in a large flow loop. We present a variety of 2-D cross-sectional images, time series velocity and concentration graphs and 3-D contour plots. The good temporal and spatial resolution of ECT throws an extensive new light on these otherwise difficult to measure dynamic flow structures. In particular with bubbly-slug structures known as ‘ghosts’ ECT shows clearly that they are in fact bubbly waves which have extended ‘wings’ up and around the pipe.

scholarly journals EVALUATION OF THE ELECTRICAL CAPACITANCE TOMOGRAPHY SYSTEM FOR MEASUREMENT USING 3D SENSOR

2019 ◽  
Vol 9 (4) ◽  
pp. 52-59
Author(s):  
Jacek Kryszyn ◽  
Damian Wanta ◽  
Waldemar T. Smolik
Keyword(s):  
Image Reconstruction ◽  
High Speed ◽  
Modular System ◽  
Capacitance Measurement ◽  
Electrical Capacitance Tomography ◽  
Electrical Capacitance ◽  
3D Image Reconstruction ◽  
Small Uncertainty ◽  
Small Change ◽  
Capacitance Tomography

Further tests of EVT4 data acquisition system for electrical capacitance tomography are presented. The modular system, which can have up to 32 channels with an individual analogue to digital converter, was designed to ensure small uncertainty of capacitance measurement at high speed of imaging. The system’s performance in the context of 3D imaging was experimentally verified. In particular, we show that the measurement of changes in capacitance due to a small change of an electric permittivity distribution for the most distant electrodes in a suitably designed 3D sensor is possible using our system. Cross-plane measurements together with the measurements for the pairs of most distant electrodes are essential for accurate reconstruction of 3D distributions. Due to sensitivity of capacitance measurements obtained in the hardware, the measurements for all electrode pairs can be used in the inverse problem – the system of equations can be extended. Although the numerical condition number of a matrix of such a system is high, image reconstruction is possible from the data obtained in our system. The results of 3D image reconstruction for simple test objects are shown.

scholarly journals Electrical Capacitance Tomography (ECT) Electrode Size Simulation Study for Cultured Cell

2021 ◽  
Vol 2071 (1) ◽  
pp. 012052
Author(s):  
N A Zulkiflli ◽  
M D Shahrulnizahani ◽  
X F Hor ◽  
F A Phang ◽  
M F Rahmat ◽  
...  
Keyword(s):  
Finite Element ◽  
Cultured Cells ◽  
Electrical Capacitance Tomography ◽  
Finite Element Models ◽  
Capacitive Sensing ◽  
Electrical Capacitance ◽  
Cross Sectional ◽  
Electrode Size ◽  
Cell Monitoring ◽  
Capacitance Tomography

Abstract Cell sensing and monitoring using capacitive sensors are widely used in cell monitoring because of the flexible and uncomplicated design and fabrication. Previous work from many different fields of applications has integrated capacitive sensing technique with tomography to produce cross-sectional images of the internal dielectric distribution. This paper carried an investigation on the capabilities of four 16-channel sensor electrodes with different electrode sizes to detect the change in the dielectric distribution of the cultured cells. All three 16-channel sensor electrodes are designed and simulate on COMSOL 6.3a Multiphysics. The pre-processing results obtained from three finite element models (FEM) of ECT sensor configurations in detecting the cell phantom shows that bigger electrodes size are more sensitive to permittivity distribution.

Investigation of the riser cross-sectional aspect ratio effect on the flow dynamics in circulating fluidized beds by electrical capacitance tomography

2019 ◽  
Vol 42 (4) ◽  
pp. 655-665
Author(s):  
Qiuya Y Tu ◽  
Haigang G Wang
Keyword(s):  
Aspect Ratio ◽  
Excitation Frequency ◽  
Electrical Capacitance Tomography ◽  
Circulating Fluidized Beds ◽  
Electrical Capacitance ◽  
Cross Sectional ◽  
Bed Height ◽  
Bottom Region ◽  
Sensitivity Map ◽  
Capacitance Tomography

With the increase of capacity, most of the circulating fluidized beds (CFB) risers are constricted to have rectangular cross section. Therefore, it is important to find out the cross-sectional aspect ratio effect on the gas-solids flow characteristics. In this study, a lab-scale CFB with two rectangular risers, which have the aspect ratio of 1:1 and 3:1, respectively, were studied by the electrical capacitance tomography (ECT), with the aided of pressure measurements and computational particle fluid dynamics (CPFD) simulation. Key issues related with ECT sensor design and image reconstruction, such as sensitivity map and excitation frequency, are also discussed. The results show that ECT image quality is affected by the sensitivity map and excitation frequency, and high excitation frequency and voltage are not equivalent of high image quality. In the riser bottom region, cross-sectional aspect ratio has big effect on ECT measured particle distribution and pressure drop, fewer particles are brought away from the bottom when the aspect ratio is larger. Multiple bubbles exist in the bottom region at Ve= 2.7 m/s, and bubble size decreases in the rectangular riser with larger cross-sectional aspect ratio. Static bed height influences the bubble behaviour that bubbles with smaller size scattered around and behave collapse or coalescence in the moving process when the static bed height is high.

Fire–Flame Imaging Using Electrical Capacitance Tomography

2012 ◽  
Author(s):  
Ruzairi Abdul Rahim ◽  
Kok Seong Chan ◽  
Sallehudin Ibrahim ◽  
Shaharum Sulaiman ◽  
Mohamad Shukri Abdul Manaf
Keyword(s):  
Reconstruction Algorithm ◽  
Visual Basic ◽  
Electrical Capacitance Tomography ◽  
Back Projection ◽  
Electrical Capacitance ◽  
Cross Sectional ◽  
Fire Flame ◽  
Linear Back Projection ◽  
Capacitance Tomography ◽  
Visual Basic 6.0

Ciri–ciri sifat pengukuran tomografik yang khusus telah terbukti dengan keupayaannya untuk memisit keadaan dinamik suatu proses dalam satu unit pengoperasian seperti dalam kebuk atau alat pengangkut tanpa memberi sebarang gangguan kepada proses tersebut. Proses Tomografi Kapasitan (Electrical Capacitance Tomography–ECT) merupakan teknik tidak intrusif untuk mengetahui taburan kandungan dalam paip dengan mengkaji perubahan ketelusan dielektrik bagi bahan yang terkandung dalam paip. Satu pengesan ECT 8 elektrod dengan pengaturcaraannya dalam Microsoft Visual Basic 6.0 telah dibinakan untuk menunjukkan paparan pengguna. Sistem ini berupaya mengetahui pembahagian api yang terbakar dalam sesuatu perkakas. Data daripada sistem perkakas akan diperolehi melalui satu unit pengawal dan dimasukkan dalam komputer untuk mendapatkan gambaran keratan rentas pembakaran api. Algoritma pembinaan semula imej (Image Reconstruction Algorithm) yang digunakan dalam projek ini adalah Unjuran Belakang Linear (Linear Back Projection LBP) yang konvensional tetapi efektif. Kata kunci: Proses Tomografi Kapasitan, pembahagian api yang terbakar, Unjuran Belakang Linear, tidak intrusif, Visual Basic The specific characteristic of tomographic measurement is its proven ability to interrogate the dynamic state of a process condition within a unit operation such as a mixing vessel or conveyor without interfering with the process itself. This is achieved using noninvasive sensors along a cross–sectional boundary of the process equipment. Electrical Capacitance Tomography (ECT) is a non–intrusive technique for obtaining information about the distribution of the contents of closed pipes by measuring variations in the dielectric permittivity of the material within the electrodes sensing region. An 8 electrode ECT sensor system with a graphical user interfacing (GUI) software programming has been developed by using Microsoft Visual Basic 6.0. This system can be used to investigate the distribution of fire flame inside the vessel. Data from the hardware system can be acquired directly to computer through a microcontroller control unit to provide the cross sectional image of the fire flame. Image reconstruction algorithm used in this project is the conventional, but effective Linear Back Projection (LBP). Key words: Electrical Capacitance Tomography, fire flame, Linear Back Projection, nonintrusive, Visual Basic

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