Wearable sensor scanner using electrical impedance tomography

• Main Author: Yao, Yongjia
• Other Authors: Soleimani, Manuchehr
• Published: University of Bath 2012
• Subjects: 621.381
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.600214

Electrical impedance tomography (EIT) is an imaging system that can generate a map of electrical conductivity. The aim of this project is to develop a pressure mapping imaging device, which we also call Wearable Scanners using EIT (WSEIT) system. WSEIT are being developed based on electrical conductivity imaging of the conductive area generated in a fabric structure. This thesis demonstrates the application of conductive fabric as a pressure mapping imaging device together with the EIT imaging system. For the first time, multiple-deformation and pressure points are detected. This thesis will also show quantitative analysis of this pressure mapping imaging solution. We envisage a number of applications for WSEIT, especially in the areas of robotics and bio-mechanics. In this project, we are interested in measuring the pressure that has been applied to a 2D surface. There are three major parts to this project: the sensor design, the hardware electronics and, finally, tomographic image reconstruction. The sensors are elastomeric conductive areas that can be integrated in a number of ways into a garment. It will be shown that the conductivity of the area will change as the surface topology changes; as pressure is applied, the electrical impedances of the sensor area are measured from a number of peripheral points. The impedance data is then transferred to the image reconstruction software. Finally, the inversion technique is applied to the data to generate a pressure and deformation map of the body. The measurement system has been developed using a multiplexer circuit and a USB-based DAQ card, from National Instruments (NI). The performance of the EIT system was tested using traditional saline phantoms. Several different types of materials have been considered and tested for the design of fabric based pressure sensor.