Subscription or Fee Access
Total variation regularization for large-scale X-ray tomography
A new large-scale computational total variation regularization algorithm is introduced and tested with examples arising from X-ray tomography with sparsely sampled data. The total variation penalty term is discretized using a basis of discontinuous functions. The approach is motivated by discontinuous Galerkin methods and leads to an additional term of the jump part of total variation. The proposed algorithm combines the usage of the jump part with a subgradient descent scheme. A comparison is provided with the gradient-based projected Barzilai-Borwein method which uses a smoothly approximated total variation penalty. The above two methods are examples of total variation regularization algorithms that can be applied to large-scale tomographic problems in reasonable computation time. A comparison between the methods shows that they use roughly equal computational resources and that the new method produces somewhat blockier reconstructions. Although the test problems are two-dimensional, both methods can be applied to three-dimensional situations as well.
X-ray tomography, First-order methods, Barzilai-Borwein, subgradient descent, total variation.
Disclaimer/Regarding indexing issue:
We have provided the online access of all issues and papers to the indexing agencies (as given on journal web site). It’s depend on indexing agencies when, how and what manner they can index or not. Hence, we like to inform that on the basis of earlier indexing, we can’t predict the today or future indexing policy of third party (i.e. indexing agencies) as they have right to discontinue any journal at any time without prior information to the journal. So, please neither sends any question nor expects any answer from us on the behalf of third party i.e. indexing agencies.Hence, we will not issue any certificate or letter for indexing issue. Our role is just to provide the online access to them. So we do properly this and one can visit indexing agencies website to get the authentic information. Also: DOI is paid service which provided by a third party. We never mentioned that we go for this for our any journal. However, journal have no objection if author go directly for this paid DOI service.