In iterative image restoration methods, implementation of efficient matrix vector multiplication, and linear system solves for preconditioners, can be a tedious and time consuming process. Differentâ€¦ (More)

Restoration of images that have been blurred by the effects of a Gaussian blurring function is an ill-posed but well-studied problem. Any blur that is spatially invariant can be expressed as aâ€¦ (More)

We consider the problem of solving ill-conditioned linear systems Ax = b subject to the nonnegativity constraint x â‰¥ 0, and in which the vector b is a realization of a random vector bÌ‚, i.e. b isâ€¦ (More)

In this paper we introduce a new preconditioner for banded Toeplitz matrices, whose inverse is itself a Toeplitz matrix. Given a banded Hermitian positive definite Toeplitz matrixT, we construct aâ€¦ (More)

Removing a linear shift-invariant blur from a signal or image can be accomplished by inverse or Wiener filtering, or by an iterative least-squares deblurring procedure. Because of the ill-posedâ€¦ (More)

Major breakthroughs in chip and software design have been observed for the last nine years. In October 2001, IBM released the worldâ€™s first multicore processor: POWER4. Six years later, in Februaryâ€¦ (More)

This paper considers the problem of nding nn matrices A k and B k that minimize jjT ? P A k B k jj F , where denotes Kronecker product, and T is a banded n n block Toeplitz matrix with banded n nâ€¦ (More)

Although image restoration methods based on spectral filtering techniques are very efficient, they can be applied only to problems with fairly simple spatially invariant blurring operators. Iterativeâ€¦ (More)