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.

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 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.

Switchless charge-discharge circuit for electrical capacitance tomography

2014 ◽  
Vol 25 (11) ◽  
pp. 115009 ◽  
Author(s):  
J Kryszyn ◽  
W T Smolik ◽  
B Radzik ◽  
T Olszewski ◽  
R Szabatin
Keyword(s):  
Discharge Circuit ◽  
Electrical Capacitance Tomography ◽  
Electrical Capacitance ◽  
Capacitance Tomography ◽  
Charge Discharge

PC Controlled Function Generator Using Direct Digital Synthesis (DDS) Technology For Electrical Capacitance Tomography

2012 ◽  
Author(s):  
Ruzairi Abdul Rahim ◽  
Chin Heng Teo ◽  
S. Sulaiman ◽  
M. S. Abdul Manaf
Keyword(s):  
Flow System ◽  
Sine Wave ◽  
High Accuracy ◽  
Electrical Capacitance Tomography ◽  
Electrical Capacitance ◽  
Direct Digital Synthesis ◽  
Function Generator ◽  
Tomography System ◽  
Digital Synthesis ◽  
Capacitance Tomography

Penjana frekuensi telah digunakan secara meluas dalam pelbagai jenis ujikaji. Ia digunakan untuk menjana pelbagai bentuk gelombang (gelombang sin, gelombang segiempat dll) pada frekuensi dan lebar jalur tertentu. Satu daripada aplikasinya ialah dalam Proses Tomografi jenis Kapasitif (ECT) di mana ia digunakan untuk menyalurkan maklumat mengenai keadaan aliran. Kertas kerja ini menjelaskan bagaimana mereka bentuk sebuah Penjana Fungsi yang Dikawal oleh Komputer Peribadi yang ekonomi untuk kegunaan ujikaji makmal. Rekaan ini berbeza dengan penjana fungsi manual kerana ia hendaklah dikawal secara digital. Dalam kes ini, teknologi DDS (Direct Digital Synthesis) digunakan kerana cip DDS adalah digital secara semulajadinya. Analisis telah dibuat untuk memeriksa ketepatan keluaran fungsi dari segi frekuensi dan amplitudnya. Kata kunci: Penjana frekuensi, sintesis secara terus (DDS) A function generator is widely used for experimental work and testing to generate various types of waveform (sine, square, triangle, etc) with a particular frequency bandwidth. One of its applications is in generating waveform for the ECT (Electrical Capacitance Tomography) system. ECT is used to retrieve the details of material in a flow system. An economical PC Controlled Function Generator was designed for the use of waveform generating in ECT. For the ECT system, high accuracy and frequency waveforms are needed. Three basic waveforms are required; the sine wave, square wave, and triangular wave. The objective is to build a function generator which is capable of generating high accuracy waveforms with acceptable distortion and stability. An interfacing system between a PC and the function generator was also selected and developed with the purpose of producing accurate amplitude and frequency of the waveforms. This interfacing allows remote control to the function generator for a wider usage. Key words: Function generator, direct digital synthesis (DDS)

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.

Sign in / Sign up

Export Citation Format

Share Document