title: Spatial resolution improvement of 3D EIT images by the shrinking sLORETA-FOCUSS algorithm.
abstract: This paper describes the use of the shrinking sLORETA-FOCUSS algorithm to improve the spatial resolution of three-dimensional (3D) EIT images. Conventional EIT yields inaccurate, low spatial resolution images, due to noise, the low sensitivity of boundary voltages to inner conductivity perturbations and a limited number of boundary voltage measurements. The focal underdetermined system solver (FOCUSS) algorithm produces a localized energy solution based on the weighted minimum-norm least-squares (MNLS) solution. It was successfully applied for the spatial resolution improvement of EIT images of simulated and tank data for a 2D homogeneous circular disc. However, due to the fact that a 3D mesh system contains many more elements, much more memory is required to store the weighting matrix. In order to extend the work to 3D, the shrinking-FOCUSS method is utilized to shrink the solution space as well as the weighting matrix in each iteration step. The solution of the standardized low resolution electromagnetic tomography algorithm (sLORETA) is adopted as the initial estimate of the shrinking-FOCUSS. The effectiveness is verified by implementing the new algorithm on tank data for a three-dimensional homogeneous sphere.
authors.affiliation: Province-Ministry Joint Key Laboratory of Electromagnetic Field and Electrical Apparatus Reliability, Department of Electrical Engineering, Hebei University of Technology, Tianjin 300130, People's Republic of China. dgy99@mails.tsinghua.edu.cn
authors.forename: Guoya
authors.initials: G
authors.lastname: Dong
authors.forename: Hesheng
authors.initials: H
authors.lastname: Liu
authors.forename: Richard H
authors.initials: RH
authors.lastname: Bayford
authors.forename: Rebecca
authors.initials: R
authors.lastname: Yerworth
authors.forename: Paul H
authors.initials: PH
authors.lastname: Schimpf
authors.forename: Weili
authors.initials: W
authors.lastname: Yan
mesh_terms: D000465:Algorithms; D000818:Animals; D001824:Body Constitution / Q000502:physiology*; D017097:Electric Impedance; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008954:Models, Biological; D019047:Phantoms, Imaging; D010992:Plethysmography, Impedance / Q000295:instrumentation / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014054:Tomography / Q000295:instrumentation / Q000379:methods*