Author: Carl Tholin-Chittenden, 2nd year PhD student in the Department of Electrical & Electronic Engineering and a member of the Engineering Tomography Lab (ETL).
I am working with Electrical Capacitance Tomography (ECT) which is a sensing technique mainly used in industry to non-invasively view inside objects such as pipelines or containers. I use this technology to image landmines underground and reconstruct 3D images to aid in their detection and removal.
Reconstructing a 3D image
Landmines are increasingly constructed of plastic with very few metal components. This makes detecting them with conventional techniques, such as metal detectors, very difficult. ECT is capable of detecting most types of materials not just metals. This is because it finds differences in electromagnetic properties of materials to their surroundings. A plastic or metallic object buried in soil or sand is going to produce very different signals to the ECT sensor than when there is only soil or sand under the sensor. This signal difference can then be reconstructed to produce a 3D image of the object.
The main difficulties with ECT are that it doesn’t reconstruct the objects with much precision (mainly just location and depth) and it can be drastically affected by different environments, such as wet ground which degrades the signal quality.
In order to improve the image reconstruction of ECT I spent my first year at Bath researching sensor head designs to see if by simply changing the shape and layout of the sensor head I could improve the image reconstruction. I found that by using many different shapes of electrode and by varying the electrode layout on the sensor I could drastically improve the image reconstructions.
Meeting Sir Bobby Charlton
My research is funded by a charity called Find A Better Way (FABW) which fund landmine detection technology research. The charity was founded by Sir Bobby Charlton and in June 2016 he came to visit my lab to see the work that I had been doing. He was very interested in the sensor design and I showed image live reconstruction of objects buried in sand to mimic landmines. I have been an avid supporter of Manchester United since I was young, so this visit was doubly amazing for me, and to have your work validated by someone as impressive as Sir Bobby has left a lasting impression on me.
Attending the WCIPT8
In September 2016 I was asked to present my work at the 8th World Congress for Industrial Process Tomography (WCIPT8) in Foz Do Iguazu, Brazil. I met many interesting people within my field with whom I could discuss my work. This gave me many ideas to bring back and apply to my research. I presented my work on sensor design, which was well received and many people had questions about the work and the software that I had developed to go alongside it. One PhD student was even interested in collaboration as the software I had developed was very similar to what he was working on.
Coming back from the conference I dived straight back into my research using everything that I had learnt. I am currently developing novel scanning techniques to improve the image reconstruction by viewing the object underground from different angles. Next I will start to design and build a sensor head which has configurable electrode shapes and layouts (the conclusion of my first year work).
To solve the problem of different environments I also aim to investigate using conductivity data in my simulations. This will mean that I can account for the wetness of the environment I am in, because wet ground has a higher conductivity that affects the electromagnetic properties of the ground around the object.
Saving and improving lives
Hopefully by combining all of these various additions to the ECT system I can show different ways in which an ECT system can be modified to be used for landmine detection. The dream would be that one day ECT is a viable method of landmine detection and that the technology I develop will be used to save lives and improve the lives of people living in areas affected by landmines.
The University of Bath will be hosting the next world congress WCIPT9 in 2018.