Salama, Abdalla Mohamed Ahmed Mahmoud
(2025)
Development of an electrical impedance tomography system for imaging and measurement applications.
MPhil thesis, University of Nottingham.
Abstract
Electrical impedance tomography (EIT) is a non-invasive imaging technique that reconstructs the internal conductivity distribution of a medium using voltage or current measurements obtained via electrodes. Despite its potential, conventional EIT systems face challenges such as hardware complexity, high computational demands, and limited adaptability for diverse applications. This research addresses these limitations by developing a novel EIT system, termed Single-Ended Electrical Impedance Tomography (SEEIT), which introduces significant advancements in both hardware design and measurement methodology.
The SEEIT system's primary innovation lies in its unique electrode configuration and measurement approach, which reduces the number of required channels by 50% compared to traditional EIT systems. Unlike conventional systems that rely on differential signaling, SEEIT employs a simplified single-ended signaling method, where only one stationary electrode acts as the receiver for each measurement. This design minimizes hardware complexity and reduces the number of computations required for image reconstruction, thereby improving efficiency and reducing data errors. Additionally, the system incorporates custom-designed titanium alloy electrodes , which enhance durability and signal quality, addressing a critical limitation of existing EIT systems.
Experimental evaluations were conducted using cylindrical tanks equipped with 16 electrodes to assess the SEEIT system's ability to detect, locate, and reconstruct images of hidden objects. Results demonstrated that the system can detect objects as small as 1.5 mm in diameter within a tank of 134 mm diameter, achieving a spatial resolution of approximately 1.1% of the tank diameter. Furthermore, the system successfully reconstructed images of multiple non-conductive object shapes, showcasing its capability for accurate spatial mapping. Stability tests confirmed robust performance, with continuous data acquisition maintained over a one-hour period without degradation in signal quality.
To enhance flexibility and adaptability, a programmable LabVIEW interface was developed, enabling the SEEIT system to be easily customized for diverse applications without requiring hardware redesign. This feature significantly reduces costs and accelerates deployment across different use cases. MATLAB, integrated with the open-source Electrical Impedance and Diffuse Optical Tomography Reconstruction Software (EIDORS) toolbox, was utilized for 2D image reconstruction based on processed data from LabVIEW.
The key contributions of this research include: (1) the development of a novel electrode configuration and measurement methodology that simplifies hardware requirements while maintaining high accuracy; (2) the demonstration of enhanced detection capabilities, including the ability to identify small objects and reconstruct non-conductive shapes; and (3) the creation of a flexible, cost-effective system adaptable to various industrial and biomedical applications. These advancements address critical gaps in current EIT technology and contribute to the broader body of knowledge by providing a more efficient and reliable solution for real-world challenges.
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