A Kalman filter approach applied to the tracking of fast movements of organ boundaries

In electrical impedance tomography (EIT) the impedance distribution is usually estimated in fixed elements (pixels) inside the object. In this case the volume changes of the organs (such as the ventricle in the heart) are seen as resistivity changes in the reconstructed images and the true volume changes are difficult to estimate. In this paper we propose an approach in which the movements of the boundaries of the organs are estimated. The method is based on expressing the boundaries as truncated radial Fourier series and the estimation of the Fourier coefficients with the aid of the Kalman smoother and the boundary element method. The feasibility of the method is shown by simulations.