AB-GMRES and BA-GMRES as Regularizing Iterations for X-Ray CT

The material on this homepage is related to the AB-GMRES and BA-GMRES iterative Krylov subspace methods (jointly referred to as ABBA methods). These methods are suited for computing reconstructions with an unmatched pair of forward and back projects, which is often the case in X-ray CT. The methods are described in the paper: We provide three Matlab functions that can be downloaded individually: We also provide Python software that implements the ABBA methods: Moreover, we provide Matlab code (also written by Maria Knudsen) that uses the ASTRA Toolbox to produce the forward and back projector pairs in the form of objects/operators or sparse matrices. The CPU version of ASTRA produces matched matched pairs; the GPU version produces unmatched pairs:

We know that not everyone may have access to ASTRA and a GPU, and hence we provide a few test problems as MATLAB mat-files in this REPOSITORY.

Please report bugs to Per Christian Hansen