Selected Technical Papers On Electrical Capacitance Tomography

World Congress Meetings on Electrical Process Tomography

There have been 5 international conferences on Electrical Tomography to-date. A full list of papers presented at each of these conferences can be viewed by clicking on one of the 5 links below.

Please contact VCIPT at the Virtual Centre for Industrial Process Tomography to obtain copies of one or more sets of these conference proceedings on CDROM.

The following is a selection of selected papers describing the design, operation and application of electrical capacitance tomography systems. We have put a few brief comments next to each title to indicate the relevant content of each paper Please contact PTL if you have difficulty in obtaining any of these publications.

1. Design Of ECT Systems

• Ref: 1-001. "Tomographic imaging of two-component flow using capacitance sensors". Huang, Plaskowski, Xie and Beck, J.Phys E:Sci Instrum.22 (1989) pp173-177.
  Comments: The first full description of the UMIST ECT system, on which PTL300 ECT systems are based. Contains a description of the LBP algorithm image reconstruction algorithm, based on the use of binary sensitivity maps

• Ref: 1-002. UK Patent GB 2214640B "Tomographic flow imaging system" 20-01-1988
  Comments: Patent describing the UMIST ECT system

• Ref: 1-003. "Capacitance-based tomographic flow imaging system", Huang, Plaskowski, Xie and Beck, Electronics Letters 31st March 1988 Vol 24 No 7 pp 418-419.
  Comments: Description of the ECT system with particular reference to the measured sensitivity distribution between electrode-pairs

• Ref: 1-004. "Recent developments and industrial/research applications of capacitance tomography", Reinecke and Mewes, Meas Sci. Technol 7 (1996), pp 233-245.
  Comments: A good review of ECT technology up to 1996, with a particularly comprehensive set of references.

• Ref: 1-005. "Electrical capacitance tomography with square sensor", Yang and Liu, Electronics Letters, 18th February 1999, Vol. 35, no. 4, pp 1-2
  Comments: Describes how ECT can be applied for use with a square sensor and describes and gives results from the use of iterative techniques to improve the image accuracy.

• Ref: 1-006. "Design of sensor electronics for electrical capacitance tomography". Huang, Xie, Thorn, Snowden and Beck, IEE Proceedings-G, Vol. 139, no. 1, February 1992 pp 83-88.
  Comments: Describes the design, characteristics and performance of the UMIST ECT system.

• Ref: 1-007. "Process tomography: a European innovation and its applications", Beck and Williams, Meas. Sci. Technol., 7, (1996), pp 215-224.
  Comments: Review paper on electrical tomography with specific references to ECT.

• Ref: 1-008. "Process Tomography - the state of the art", Beck, Dyakowski and Williams, Trans Inst MC, Vol. 20, No. 4, 1998.
  Comments: Review paper on electrical tomography with specific references to ECT.

• Ref: 1-009. "Calibration of capacitance tomography systems: a new method for setting system measurement range", Yang, Meas. Sci Technol 7, (1996), pp 863-867.
  Comments: Discussion of calibration methods for ECT.

• Ref: 1-010. "Electrical capacitance tomography for flow imaging: system model for development of image reconstruction algorithms and design of primary sensors", Xie, Huang, Hoyle, Thorn, Lenn, Snowden and Beck, IEE Proceedings - G, Vol. 139, No. 1, February 1992.
  Comments: Title accurately describes contents of paper.

• Ref: 1-011. "Experimental evaluation of capacitance tomographic flow imaging systems using physical models", Xie, Huang, Lenn, Stott and Beck, IEE Proc. - Circuits Devices Syst., Vol. 141, No. 5, October 1994.
  Comments: Experimental evaluation of ECT using test objects.

• Ref: 1-012. "A mathematical model for the multi-electrode capacitance sensor", Oakley and Bair, Meas. Sci. Technol. 6 (1995) pp 1617-1630.
  Comments: Derivation of a model for the relationship between permittivity change and capacitance change inside a circular ECT sensor.

  
  

2. Image Reconstruction Methods

• Ref: 2-001. "Electrical capacitance tomography for flow imaging: system model for development of image reconstruction algorithms and design of primary sensors". Xie, Huang, Hoyle, Thorn, Lenn, Snowden and Beck, IEE Proceedings-G, Vol. 139, no. 1, February 1992
  Comments: Detailed information on the image reconstruction methods used in the UMIST ECT system.

• Ref: 2-002. "A review of reconstruction techniques for capacitance tomography", Isaacson, Meas Sci. Technol 7 (1996), pp 325-337.
  Comments: The title accurately describes the contents of this paper

• Ref: 2-003. "Optimisation of an iterative image reconstruction algorithm for electrical capacitance tomography", Liu, Fu and Yang, Meas. Sci. Technol. 10 (1999) L37-L39.
  Comments: Descibes how an optimisation technique for determining the gain applied to the feeedback loop of an iterative algorithm can cause the algorithm to converge rapidly to produce an optimum image.

• Ref: 2-004."An improved normalisation approach for electrical capacitance tomography", Yang and Byars, Proceedings of the 1st World congress on Industrial Process Tomography, Buxton, England, April 1999.
  Comments: Describes how the use of a series capacitance model can improve the accuracy of ECT images for lean phase applications.

• Ref: 2-005. "An image reconstruction algorithm basased on Landweber's iteration method for electrical -capacitance tomography", Yang, Spink, York and McCann, Meas. Sci. Technol. 10(1999) pp1065-1069.
  Comments: A good description of iterative image reconstruction methods.

• Ref: 2-006. "Application of conjugate harmonics to electrical process tomography", Ostrowski, Luke and Williams, Meas. Sci. Technol. 7 (1996) pp 316-324.
  Comments: An analytical method for solving the electric field distribution inside an ECT sensor.

  
  

3. Applications Of ECT

• Ref: 3-001. "Experimental evaluation of capacitance tomographic flow imaging systems using physical models". Xie, Huang, Lenn,Stott and Beck, IEE Proceedings-Circuits Devices Syst., Vol. 141, no. 5, October 1994 1992
  Comments: Results of experiments comparing physical phantoms with ECT images.

• Ref: 3-002."Electrical capacitance tomography measurements of gravity-driven granular flows", Hua and Wang, Ind. Eng. Chem. Res., 1999, 38 pp 621-630.
  Comments: A detailed description of the use of twin-plane ECT and correlation techniques to measure the flow of particles falling under gravity in a vertical tube. The flow measurements were checked against a load cell and good agreement was obtained.

• Ref: 3-003."Combustion imaging from electrical impedance measurements", Waterfall, He, White and Beck.
  Comments:Describes how ECT can be used to image flames and combustion with experimental results.

• Ref: 3-004."Calibration of capacitance tomography systems for liquid-liquid dispersions", Bolton, Korchinsky and Waterfall, Meas. Sci. Technol. 9 (1998) pp 1797-1800.
  Comments: Describes some of the problems of calibrating ECT systems for use with water.

• Ref: 3-005."Real-time visualisation and analysis of dense-phase powder conveying", Ostrowski, Luke, Bennett and Wiliams, Powder Technology, 102 (1999) pp 1-13.
  Comments: Describes the use of ECT to monitor powder flow in a pneumatic conveying rig.

• Ref: 3-006."Measurement of bulk particulates on a belt conveyor using dielectric tomography", Williams, Luke, Ostrowski and Bennett, Proceedings of the 1st International Symposium on on-line flow measurement of particulate solids, University of Greenwich, 14-15 July 1998.
  Comments: Describes the use of ECT to monitor particle flow on a belt conveyor.

• Ref: 3-007."Real time imaging of dense phase particulate flows in conveying and fluidisation", Williams, Luke, Ostrowski and Dyakowski, Proceedings of the 1st International Symposium on on-line flow measurement of particulate solids, University of Greenwich, 14-15 July 1998.
  Comments: Contents as title.

• Ref: 3-008."Visualisation of transient two-phase flows using multi-electrode capacitance sensors for electrical tomography", Reinecke and Mewes, International symposium on two-phase flow modelling and experimentation, Italy, October 1995.,
  Comments: Use of ECT to measure liquid flows in trickle-bed reactors.

• Ref: 3-009."Monitoring water hammer by capacitance tomography", Yang, Adam, Watson and Beck, Electronics Letters, 12 September 1996, vol. 32, no. 19.
  Comments: Use of ECT to monitor water hammer in long pipelines.

• Ref: 3-010."Analysis and flow regime identification of bubble column dynamics", Bennett, Luke, Jia, West, and Williams, Proceedings of the 1st World congress on Industrial Process Tomography, Buxton, England, April 1999.
  Comments: Similar to ref: 3-006.

• Ref: 3- 011. "Measurement of Bulk Particulates on belt conveyor using Dielectric tomography", Williams., Luke, Ostrowski and Bennett, Proceedings of the 1st World congress on Industrial Process Tomography, Buxton, England, April 1999.
  Comments: Similar to ref: 3-006.

• Ref: 3-012."Monitoring flame position and stability in combustion cans using ECT", Waterfall, He, Wolanski and Gut, Proceedings of the 1st World congress on Industrial Process Tomography, Buxton, England, April 1999.

• Ref: 3-013. "Internal structures in fluid beds of different scales: an application of electrical capacitance tomography", White and Zakhari, Proceedings of the 1st World congress on Industrial Process Tomography, Buxton, England, April 1999.
  Comments: ECT imaging of fluidisation of alumina particles in different diameter fluidised beds.

• Ref: 3-014. "ECT studies of bead fluidisation in vertical mills", Scott and Gutsche,, Proceedings of the 1st World congress on Industrial Process Tomography, Buxton, England, April 1999.
  Comments: Use of ECT to measure the media packing and fluidisation in an agitated vertical mill.

• Ref: 3-015."Particle extraction using process CT and Wavelets", Takei, Li, Ochi, Saito, Horii and Dyakowski, Proceedings of the Second Japanese-European 2-phase flow group meeting, Tsukuba, Japan, September 25-29, 2000.
  Comments: Use of wavelet analysis to improve accuracy of ECT data for concentration profile measurement in a powder-conveying pipeline.

• Ref: 3-016. "Imaging immiscible liquid-liquid systems by capacitance tomography", Bolton, Korchinsky and Waterfall, Trans IChemE, Vol 77, Part A, November 1999, pp 699-708.
  Comments: Use of ECT to image water droplets in kerosene.

• Ref: 3-017. "Imaging nylon polymerisation processes by applying electrical tomography", Dyakowski, York, Mikos, Vlaev, Mann, Follows, Boxman and Wilson, Chemical Engineering Journal, 77, (2000) pp 105-109.
  Comments: Title accurately describes contents of paper.

  
  

4. Multiphase Flow Measurement Using ECT

• Ref: 4-001."Non-intrusive Measurement of Volume and Mass using Electrical Capacitance Tomography", Andrew Hunt, John Pendleton and Malcolm Byars. ESDA2004, Manchester UK, 19-22 July 2004.

• Ref: 4-002. "A Novel Tomographic Flow Analysis System", Andrew Hunt, John D Pendleton and Robert B White, 3rd World Congress on Industrial Process Tomography, Banff, Canada. September 2003.

  Comments: A novel flow analysis system is described which uses twin-plane tomographic data to derive detailed pictures of the velocity and concentration structure within complex two-phase flows. Initial results have been obtained using electrical capacitance tomography (ECT) but other modalities may also be used. By defining a set of contiguous zones over the flow cross-section the full integration of flowrate may be undertaken and a mass flowmeter created for two-phase systems. A number of flows have been analysed, and detailed results from selected tests are presented. The simplest experiments consist of solid particles dropped under gravity through a 50mm diameter pipe, which approximates the conditions at the exit of an industrial storage hopper. More complex flows were generated in a recirculating flow rig and are typical of conditions in an industrial pneumatic conveying line. The ECT flow analysis results can be used to explore the detail of complex structures and velocity fields while comparisons with computational fluid dynamics models, high-speed video and other measurements show that the ECT results are consistent and accurate to within a few per cent of the true value.

• Ref: 4-003."Visualisation of Two-phase Gas-Liquid Pipe Flows using Electrical Capacitance Tomography",A. Hunt, J. Pendleton and Y. Ladam, ESDA2004, Manchester UK, 19-22 July 2004.

• Ref: 4-004. Measurement of Velocity and Mass of Moving Structures in Industrial Flows using Electrical Capacitance Tomography",Andrew Hunt, John D Pendleton and Malcolm Byars, Medical Applications of Electrical Impedance Tomography, UMIST, Manchester UK, 23-25 April 2003.

• Ref: 4-005."Cross-correlation flowmeters: their design and application",Beck M.S. and Plaskowski A. (1987) IOP Publishing, Bristol, UK.

  
  

5. Some Other Relevant Papers

• Ref: 5-001."Capacitance transducers for concentration measurement in multi-component flow processes", Huang, Green, Stott and Beck, Proceedings of the 3rd International Conference on Multiphase flow, The Hague, the Netherlands, May 1987.
  Comments: Describes how multiphase flow can be measured using an array of capacitance transducers.

• Ref: 5-002. "Flow imaging for multi-component flow measurement", Plaskowski, Beck and Krawaczynski, Trans. Inst. M.C. Vol. 9, no. 2, April-June 1987.
  Comments: Describes how multiphase flow can be measured using concentration and velocity profiles.

• Ref: 5-003."Comparison of the use of internal and external electrodes for the measurement of the capacitance and conductance of fluids in pipes", Stott, Green and Seraji, J. Phys. E: Sci.Instrumen., vol. 18, 1985.
  Comments: See title. Useful paper for understanding the choice between capacitance sensors with internal and external electrodes.

• Ref: 5-004. Textbook, "Capacitive sensors", Baxter, IEEE press, ISBN 0-7803-11.30-2.
  Comments: A mine of practical information on capacitive sensor design.

Last updated: 26-11-2004