title: PET regularization by envelope guided conjugate gradients.
abstract: The authors propose a new way to iteratively solve large scale ill-posed problems and in particular the image reconstruction problem in positron emission tomography by exploiting the relation between Tikhonov regularization and multiobjective optimization to obtain iteratively approximations to the Tikhonov L-curve and its corner. Monitoring the change of the approximate L-curves allows the authors to adjust the regularization parameter adaptively during a preconditioned conjugate gradient iteration, so that the desired solution can be reconstructed with a small number of iterations.
authors.affiliation: Lucent Technol., AT&T Bell Labs., Murray Hill, NJ.
authors.forename: L
authors.initials: L
authors.lastname: Kaufman
authors.forename: A
authors.initials: A
authors.lastname: Neumaier