The preconditioned conjugate gradient (CG) is often applied in image reconstruction as a regularizing method. When the blurring matrix has Toeplitz structure, the modified circulant preconditioner and the inverse Toeplitz preconditioner have been shown to be effective. We introduce here a preconditioner for symmetric positive definite Toeplitz matrices based on a trigonometric polynomial fit which has the same effectiveness of the previous ones but has a lower cost when applied to band matrices. The case of band block Toeplitz matrices with band Toeplitz blocks (BTTB) corresponding to separable point spread functions is also considered.
|Autori interni:||MENCHI, ORNELLA|
|Autori:||FAVATI P; LOTTI G; MENCHI O|
|Titolo:||A Polynomial Fit Preconditioner for Band Toeplitz Matrices in Image Reconstruction|
|Anno del prodotto:||2002|
|Digital Object Identifier (DOI):||10.1016/S0024-3795(01)00513-4|
|Appare nelle tipologie:||1.1 Articolo in rivista|