Improved EIT drive patterns for a robotics sensitive skin

Electrical impedance tomography (EIT) is a technique used to estimate the internal conductivity of an electrically conductive body by using only measurements from its boundary. If this body is made of a thin, flexible and stretchable material that responds to touch with local changes in conductivity, it can be used to create an artificial sensitive skin. Mathematically, the EIT reconstruction problem is an ill-posed nonlinear inverse problem in which it is commonly assumed that electrodes are only located on the boundary. In a thin sensitive skin, however, electrodes can readily be located within the body. This paper compares existing drive patterns with new patterns in which a reference electrode is located inside the body. Simulation results demonstrate that placing a reference electrode in the centre of the body can improve both the resolution and robustness to noise of the reconstructed image.