- Guided-path tomography
- Temperature, concentration and pressure tomography
- Hard-field THz tomography
- Real-time reconstruction for limited data tomography
- Soot Imaging in aero-engine exhausts
- Tomography for metal production processes
- Electromagnetic tomography techniques for security applications
- Medical applications of electrical
- Optoelectronic gas sensing
- Quantifying gas-liquid production to improve productivity and reservoir management
- Online measurement of pharmaceutical fluidised beds
- Shoe scanner for airport security
- Induction tomography for two phase flow measurement
- Optimisation of metal detector design through EM modelling
We pioneered GPT in 2005, as a new type of tomography capable of imaging on curved surfaces. The first demonstration has been of temperature tomography in secondary contrast, calculated from the images of resistivity on a surface which can deviate from being strictly flat. The photonic version of GPT employs plastic optical fibres for the measurement of path integrals of light attenuation caused by fibre deformation. Depending on the way the fibre is sensitised, our GPT-based iMAGiMAT™ technology can image the footprints of objects weighing from a couple of kg to the full weight of an adult human.
Temperature, concentration and pressure tomography
Tomography cannot image temperature directly since temperature, because of its nature, cannot be integrated along a certain path in space. We extract the concentration, temperature and pressure of a molecular species of interest from a large number of reconstructed monochromatic images of absorption.
The illustration shows by simulations that the three functions are reconstructed without “cross-talk” artefacts between them.
This approach is enhanced by its application to an annular surface topology, where the central part is inaccessible, which is relevant to turbine engine research and development.
Hard-field THz tomography
Together with new opportunities, THz Tomography offers numerous challenges one of which is to realise hard-field tomography. We achieve this by using straight-line propagating “ballistic” photons, which we detect by spatial and temporal filtering. Due to improved measurements of the THz pulse delay from THz time-domain spectroscopy with a biased-gap antenna we determine the line integrals with better accuracy, leading to high-quality reconstructions of the refractive index. The illustration shows a phantom object with THz refractive index close to that of a flame, opening the way to imaging in sooty flames, which are opaque to IR radiation.
Real-time reconstruction for limited data tomography
Limited access to the imaged object degrades tomography imaging because of limited data. In such circumstances we focus only on the main constituents on the imaged scene by applying a sinusoidal Hough transformation on the measurements. By parallel computation on an FPGA, we calculate the reconstructed position of these constituents in real time for data frame rates potentially acquired at up to 40 KHz, independent of the number of these constituents and the number of the angular projections. This is improvement of between 3 to 4 orders of magnitude, at a smaller error margin, compared to sequential reconstruction algorithms.
Soot Imaging in aero-engine exhausts
The FLITES project, funded by EPSRC, aims to establish a world-leading capability in the measurement and imaging of molecular and particulate species in gas turbine aero-engine exhausts. This currently ongoing project builds upon the expertise of the UK's world-leading groups in fibre-lasers, gas-detection opto-electronics, and tomography, combined with industrial strengths in aero-engine manufacture and aviation fuel technology. Soot will be imaged via the novel technique of near-IR long-pulse Laser-Induced Incandescence, in a planar tomographic set-up previously invented in Manchester for the fluorescence case. The technique developed in the university laboratories are currently being transferred on a full-scale aero-engine mounted on a test bed at Rolls-Royce.
Tomography for metal production processes
Continuous casting is a process whereby molten metal is solidified into billets or slab and is the predominant method of steel production in the world. The molten steel is poured from the ladle into the tundish and from there through a submerged entry nozzle (SEN) into the mould where it starts to solidify. Determining the properties of the molten steel flow through the SEN and into the mould is critical in achieving an adequate control of steel cleanliness and surface quality during the continuous casting process. Due to the opaqueness of the SEN tube and its high temperature environment (over 1000 °C), it is particularly difficult to monitor the steel flow in the nozzle. This represents an extremely challenging application for industrial tomography. At Manchester we have pioneered the application of electromagnetic induction tomography taking the method from first principle lab experiments to plant application. Recently we have been working with Helmholtz- Zentrum Dresden-Rossendorf in Germany to combine tomographic imaging of the SEN with induction flow tomography in the mould.
- X Ma, A J Peyton, S R Higson and P Drake, Development of multiple frequency electromagnetic inductionsystems for steel flow visualization, Meas. Sci. Technol., 19 (9), 094008, 2008
- S R Higson, P Drake, A Lyons, A Peyton and B Lionheart, Electromagnetic visualisation of steel flow incontinuous casting nozzles, Ironmaking and Steelmaking, 33 (5), pp. 357-361, 2006
- N Terzija, W Yin, G Gerbeth, F Stefani, K Timmel, T Wondrak and A J Peyton, Use of electromagneticinduction tomography for monitoring liquid metal/gas flow regimes on a model of an industrial steel caster, Meas. Sci. Technol., 22 (1), 015501 (8pp), 2011
- Th Wondrak, S Eckert, G Gerbeth, K Klotsche, F Stefani, K Timmel, A J Peyton, N Terzija, and W Yin, Combined Electromagnetic Tomography for Determining Two-phase Flow Characteristics in the Submerged Entry Nozzle and in the Mold of a Continuous Casting Model, Met & Mat Trans. B, 42B, pp.1201- 1210, 2011
- Th Wondrak, S Eckert, V Galindo, G Gerbeth, F Stefani, K Timmel, A J Peyton, W Yin and S Riaz, Liquid metal experiments with swirling flow submerged entry nozzle, Ironmaking & Steelmaking, 39 (1), pp. 1-9, 2012
Electromagnetic tomography techniques for security applications
Walk-through metal detection (WTMD) has proven to be a fundamental part of the screening of large numbers of personnel for potential threat objects and WTMD use is widespread in locations such as airports, prisons, embassies, ports and government buildings. In these scenarios their primary purpose is to keep prohibited metallic items such as knives, guns and components of explosive devices out of a secured area. Future WTMD#s need to focus upon the use of technology which is both intelligent and sensitive in equal measures. It is necessary to go beyond the straightforward detection of metallic items by recovering detailed information about potential threat objects; this information may include the specific location, approximate dimensions and orientation of the threat object as well as additional material properties. At Manchester we have pioneered systems that can locate to cm accuracy in 3D and classify objects according to their tensor response. This work is in collaboration with Rapiscan System, Manchester Airport and Tampere University of Technology. Example output from a system coupled with video technology from tests at Manchester Airport. The green / red spot tracks the wrist watch worn by the stewardess.
We are now working to apply these tensor based classification techniques to humanitarian demining applications to help address the problem of false positives from metallic clutter with the charity Find a Better Way.
Medical applications of electrical impedance tomography
The University of Manchester has a long history of developing EIT hardware. Our most recent EIT instrument is aimed at medical applications and has been used in clinical investigations, in collaboration with clinicians from local NHS hospital trusts. The system has been applied to both cranial and thoracic imaging.
Optoelectronic gas sensing
Laser diodes provide a highly controllable source of light at wavelengths suitable for the detection of many gases of interest, including common pollutants. We have previously developed systems for the quantitative tomographic imaging of chemical species including hydrocarbon fuels and water vapour (as a product of combustion), and are currently working on the imaging of carbon dioxide distribution in the exhaust of commercial jet engines, in collaboration with Rolls-Royce, Shell and other leading academic groups.
Quantifying gas-liquid production to improve productivity & reservoir management
Currently, all multiphase flow meters deployed in the gas and oil industry use radioactive sources, which is harmful and expensive. The aim of this £1.24 million project, funded by the TSB Technology Programme (TP/8/OIL/6/I/Q2521G), 2008-2012, was to develop a new type of non-radioactive gas-oil-water flow meter by a combination of electrical capacitance tomography (ECT), microwave impedance probes, microwave Doppler sensors, ultrasonic sensors and Venturi, in collaboration with Schlumberger Gould Research in Cambridge and TUV-NEL in Glasgow. A prototype multi-sensor assembly was tested on TUV-NEL’s Multiphase Flow Facility with crude oil successfully, with +/-3% measurement error in a wide range of water-to-liquid ratios (WLR) and hence the feasibility has been demonstrated. This work resulted in four patents filed by Schlumberger and a commercialisation plan has been made to bring the outcome of this project to the market.
- Wuqiang Yang, Yi Li, Zhipeng Wu, Dimitrios Tsamakis, Cheng-Gang Xie, Songming Huang, Chris Lenn and Annette Cutler, Multiphase Flow Measurement by Electrical Capacitance Tomography, Proc. of IST’2011, 17-18 May 2011, Penang, Malaysia, pp 108-111
- Yi Li, Wuqiang Yang, Cheng-gang Xie, Songming Huang, Zhipeng Wu, Dimitrios Tsamakis and Chris Lenn, Gas/oil/water flow measurement by electrical capacitance tomography, Meas. Sci. and Technol., 24 (7), 2013, 074001 (12pp)
Online measurement of pharmaceutical fluidised beds
Currently, the understanding of the behaviour of batch fluidised beds in the pharmaceutical industry is still poor. As a result, the fluidised beds are operated by trial-and-error, resulting in low efficiency, more pollution to the environment and more importantly the product quality cannot be guaranteed. By the use of a combination of mathematical modelling, CFD simulation and electrical capacitance tomography (ECT), detailed characteristics unknown before have been obtained and used to measure fluidised bed dryers in the pharmaceutical industry. In collaboration with GEA and AstraZeneca, online measurement of solids moisture distribution in a production-scale fluidised bed – FlexStream (1 m in diameter and 6 m high) using an ACECT system has been demonstrated in GEA (Switzerland) first time in the world.
A patent (WO/2009/030876) has been filed by University of Manchester Intellectual Property (UMIP) Ltd to cover EU, USA, Australia, China and India. This work was selected as 2009 IET Innovation Award Finalist and was continuously funded by EPSRC:
- EPSRC Responsive “Product quality control of fluidised bed dryers with tomographic imaging and online process modelling” (GR/T29383/01) in collaboration with Oxford University (GR/T29376/01), 2005-2008
- EPSRC Follow-on Fund “Online pharmaceutical granule moisture distribution measurement and feedback control of fluidised bed dryer” (EP/G005702/1), 2008-2009
- EPSRC/Finance South-East Collaboration Fund “Online measurement of moisture distribution in pharmaceutical fluidised beds for drying, granulation and coating” (EP/H502327/1), 2010-2011
- H G Wang, W Q Yang, P Senior, R S Raghavan and S Duncan, Investigation of batch fluidised bed drying by mathematical modelling, CFD simulation and ECT measurement, AIChE J., 54 (2), 2008, pp 427-444
- H G Wang, P Senior, R Mann and W Q Yang, Online solids moisture measurement and optimum control of fluidised bed dryer, Chem. Eng. Sci., 64, 2009, pp 2893-2902
- H G Wang and W Q Yang, Measurement of fluidised bed dryer by different frequency and different normalisation methods with electrical capacitance tomography, Powder Technol., 199 (1), 2010, pp 60-69
- H G Wang and W Q Yang, Scale-up of electrical capacitance tomography sensor for imaging pharmaceutical fluidised beds and validation by computational fluid dynamics, Meas. Sci. and Technol., 22 (10), 2011, 104015 (11 pp)
Shoe scanner for airport security
Due to the threat of shoe bombs at airports, passengers are asked to stop and remove their shoes to be checked by an X-ray machine, which can detect metallic objects, but cannot identify plastic explosives. Working with ICIR Inc. (USA), KonsultEurope (UK), Manchester Airport, Dallas/Fort Worth Airport (USA) and University of Manchester Aerospace Research Institute, we have developed the first capacitance-based shoe scanner in the world, which can produce real-time images of passenger footprints when passengers are walking through the shoe scanner. This technology will be able to detect dangerous objects such as plastic explosives and ceramic knives hidden in the soles of shoes by generating display images of shoes. Supported by EPSRC KTA, we worked with Manchester Airport to install shoe scanners. The real-time shoe scanner could significantly improve airport security by providing a cheap and reliable solution to detect dangerous objects. A patent (WO 2005/036207 A2) was filed to cover US, EU and Japan. This work was reported by Guardian, Telegraph, Manchester Evening News, Granada TV, UniLife and many other media.
Induction tomography for two phase flow measurement
Monitoring of the steel flow through the submerged entry nozzle (SEN) during continuous casting presents a challenge for the instrumentation system because of the high temperature environment and the limited access to the nozzle in between the tundish and the mould. The electromagnetic inductance tomography (EMT) presents an attractive tool to visualize the steel flow profile within the SEN. EMT uses inductive coupling between sensors to provide images that represent the distributions of electrically conductive and/or magnetically permeable material within the object space. This work was supported by European Commission.
Optimisation of metal detector design through EM modelling
Industrial metal detectors are used in the pharmaceutical, food, beverage, textile, garment, plastics, chemicals, lumber, and packaging industries. Advanced EM modelling techniques developed at the University of Manchester are being exploited to improve sensitivity and discrimination ability of the current instruments on the market. This project is funded by Safeline - a global market leader in the field of industrial metal detection (MD).