Image reconstruction by nonlinear Landweber iteration for complicated distributions

In electrical capacitance tomography (ECT), a sensitivity matrix is usually calculated based on high permittivity perturbation with a low permittivity background and a fixed sensitivity matrix is used for both one-step and linear iterative image reconstruction. This paper presents a nonlinear iterative method with the sensitivity matrix updated during the iterative process. Using an updated sensitivity matrix, both the forward and inverse problems can be solved more accurately than using a fixed sensitivity matrix. Some complicated distributions, including ‘sun-rise’, cross, T and V shapes, have been examined using an 8-electrode sensor, with both noise-free simulation data and real measurements. The results are promising.