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.

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.

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.

An Electrical Capacitance Tomography System with Double Measurement Channels

2011 ◽  
Vol 204-210 ◽  
pp. 1314-1317
Author(s):  
Hua Yan ◽  
Jun Wang ◽  
Ying Gang Zhou
Keyword(s):  
Electrical Capacitance Tomography ◽  
Electrical Capacitance ◽  
Single Measurement ◽  
Idle Mode ◽  
Tomography System ◽  
Mode Detection ◽  
Detection Mode ◽  
Measurement Channels ◽  
Capacitance Tomography ◽  
Double Measurement

An ECT data acquisition system usually has N-1 measurement channels or single measurement channel. In order to solve the contradiction between system speed and system cost, a 16-electrode electrical capacitance tomography system with double measurement channels has been designed. It has good anti-noise ability and stray-immunity by using ac-based capacitance measuring circuits. A switch network is used to set each electrode at excitation mode, detection mode or idle mode. The influence of switch coupling capacitances is discussed and its soft compensation method is proposed. By using LabVIEW, remote monitoring and distributing data or images over network can be implemented easily.

scholarly journals METHODS OF SMALL CAPACITANCE MEASUREMENT IN ELECTRICAL CAPACITANCE TOMOGRAPHY

2017 ◽  
Vol 7 (1) ◽  
pp. 105-110 ◽  
Author(s):  
Waldemar Smolik ◽  
Jacek Kryszyn ◽  
Tomasz Olszewski ◽  
Roman Szabatin
Keyword(s):  
Sine Wave ◽  
Capacitance Measurement ◽  
Synchronous Detector ◽  
Electrical Capacitance Tomography ◽  
Wave Excitation ◽  
Electrical Capacitance ◽  
Small Capacitance ◽  
Capacitance Tomography ◽  
Discharge Method ◽  
Charge Discharge

The paper presents the main methods of small capacitance measurement used in electrical capacitance tomography: the AC method with a sine wave excitation and the charge-discharge method with square wave excitation. Construction of synchronous detector for both circuits was discussed. A modified "charge-discharge" method was presented.

DESIGN OF FLEXIBLE ELECTRICAL CAPACITANCE TOMOGRAPHY SENSOR

2015 ◽  
Vol 77 (28) ◽  
Author(s):  
MT Masturah ◽  
MHF Rahiman ◽  
Zulkarnay Zakaria ◽  
AR Rahim ◽  
NM Ayob
Keyword(s):  
Outer Layer ◽  
Electrical Capacitance Tomography ◽  
Electrical Capacitance ◽  
Capacitance Tomography ◽  
Fluid Imaging

This paper discussed the design–functionality and application of Flexible Electrical Capacitance Tomography sensor (FlexiECT). The sensors consist of 12 electrodes allocated surrounding the outer layer of the pipeline. The sensor is designed in such that the flexibility features suit the applications in the pipeline of multiple size. This paper also discussed the preliminary result of FlexiECT applications in fluid imaging by identifying the percentage of two mixing fluids.

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.

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