Time series of EIT chest images and singular value decomposition

The data being analysed were obtained from an electrical impedance tomograph comprising 32 independently programmable current sources and 32 voltage measurement channels attached respectively to separate electrodes around the chest of a male volunteer. Each image was obtained by applying-in sequence-the first 20 spatial trigonometric current patterns. Two sequences of images were made, the first during normal breathing. The second set of images were made while the subject held his breath, thus removing the respiratory element from the data and allowing the cardiac-synchronous component to be more obvious. The reconstruction problem is nonlinear and highly ill-posed. Time series and SVD of the matrix of temporal mean are presented