REGULARIZED MODIFIED NEWTON-RAPHSON TECHNIQUE APPLIED TO ELECTRICAL-IMPEDANCE TOMOGRAPHY

Electrical Impedance Tomography (EIT) is gaining importance as a monit oring tool for process engineering. The main reasons for this are its nonintrusive measurement property and its relatively cheap hardware. H owever, the image reconstruction still remains a problem especially un der heavy process conditions with little prior information. Many resea rchers have devoted their attention to this problem, but robust algori thms working on real noisy data are scarce. The authors present a regu larized, modified Newton-Raphson algorithm that gives satisfying resul ts on both static and dynamic processes. The number of pixels used by the algorithm are identical to the number of true non-zero eigenvalues , thereby diminishing the effect of ill-conditioning. The algorithm us es a user-defined pixel mesh that is mapped onto a standard finite-ele ment mesh so that the user is able to easily adapt the mesh to the pro blem under investigation. (C) 1998 John Wiley & Sons, Inc.