@article {2356, title = {Discrete tomographic reconstruction via adaptive weighting of gradient descents}, journal = {Computer Methods in Biomechanics and Biomedical Engineering: Imaging \& Visualization}, volume = {3}, year = {2015}, month = {Feb 2014}, pages = {101-109}, publisher = {Taylor\&Francis}, type = {Journal article}, chapter = {101}, abstract = {

Discrete tomography (DT) is a set of tools for reconstructing the inner structure of objects consisting of only few different homogeneous materials. We propose a new method for multivalued DT, which performs the reconstruction as an energy minimisation task. For this algorithm, we define an energy function that can mathematically formulate the reconstruction task, and design a novel optimisation process for approximating the minima of this energy function. We validate the algorithm by comparing its performance with other cutting-edge reconstruction algorithms from the literature. We show that our method can compete with the currently used reconstruction techniques and under certain circumstances (e.g. with a low number of projections, or when the projection data are affected by random noise) it can even outperform them.

}, doi = {DOI: 10.1080/21681163.2013.853624}, author = {L{\'a}szl{\'o} G{\'a}bor Varga and P{\'e}ter Bal{\'a}zs and Antal Nagy} } @conference {2360, title = {Id{\H o}skori makula degener{\'a}ci{\'o} kvantitat{\'\i}v jellemz{\'e}se SD-OCT k{\'e}pek automatikus elemz{\'e}s{\'e}vel}, booktitle = {A XXVIII. Neumann Kollokvium konferencia-kiadv{\'a}nya}, year = {2015}, month = {Nov 2015}, pages = {43-48.}, publisher = {Neumann J{\'a}nos Sz{\'a}m{\'\i}t{\'o}g{\'e}p-tudom{\'a}nyi T{\'a}rsas{\'a}g}, organization = {Neumann J{\'a}nos Sz{\'a}m{\'\i}t{\'o}g{\'e}p-tudom{\'a}nyi T{\'a}rsas{\'a}g}, type = {Conference paper}, address = {Veszpr{\'e}m, Hungary}, author = {L{\'a}szl{\'o} G{\'a}bor Varga and Melinda Katona and Tam{\'a}s Gr{\'o}sz and J{\'o}zsef Dombi and Attila Kov{\'a}cs and R{\'o}zsa D{\'e}gi and L{\'a}szl{\'o} G Ny{\'u}l} } @inbook {1990, title = {K{\'e}pfeldolgoz{\'a}s a szegedi informatikus-k{\'e}pz{\'e}sben}, booktitle = {Informatika a fels{\H o}oktat{\'a}sban 2014}, year = {2014}, month = {2014}, pages = {667-675}, publisher = {University of Debrecen}, organization = {University of Debrecen}, type = {Conference paper}, address = {Debrecen, Hungary}, issn = {978-963-473-712-4}, author = {P{\'e}ter Bal{\'a}zs and Endre Katona and Zoltan Kato and Antal Nagy and G{\'a}bor N{\'e}meth and L{\'a}szl{\'o} G{\'a}bor Ny{\'u}l and K{\'a}lm{\'a}n Pal{\'a}gyi and Attila Tanacs and L{\'a}szl{\'o} G{\'a}bor Varga}, editor = {Roland Kunkli and Ildik{\'o} Papp and Ed{\'e}n{\'e} Rutkovszky} } @article {1170, title = {Local and global uncertainty in binary tomographic reconstruction}, journal = {COMPUTER VISION AND IMAGE UNDERSTANDING}, year = {2014}, note = {Art. No.: S1077-3142(14)00117-9doi: 10.1016/j.cviu.2014.05.006Article in Press}, month = {2014}, type = {Journal article}, abstract = {

In binary tomography the goal is to reconstruct the innerstructure of homogeneous objects from their projections. This is usually required from a low number of projections, which are also likely to be affected by noise and measurement errors. In general, the distorted and incomplete projection data holds insufficient information for the correct reconstruction of the original object. In this paper, we describe two methods for approximating the local uncertainty of the reconstructions, i.e., identifying how the information stored in the projections determine each part of the reconstructed image. These methods can measure the uncertainty of the reconstruction without any knowledge from the original object itself. Moreover, we provide a global uncertainty measure that can assess the information content of a projection set and predict the error to be expected in the reconstruction of a homogeneous object. We also give an experimental evaluation of our proposed methods, mention some of their possible applications, and describe how the uncertainty measure can be used to improve the performance of the DART reconstruction algorithm.

}, isbn = {1077-3142}, doi = {10.1016/j.cviu.2014.05.006}, author = {L{\'a}szl{\'o} G{\'a}bor Varga and L{\'a}szl{\'o} G{\'a}bor Ny{\'u}l and Antal Nagy and P{\'e}ter Bal{\'a}zs} } @conference {1159, title = {Gradiens m{\'o}dszerek automatikus s{\'u}lyoz{\'a}s{\'a}n alapul{\'o} diszkr{\'e}t tomogr{\'a}fiai elj{\'a}r{\'a}s}, booktitle = {A K{\'e}pfeldolgoz{\'o}k {\'e}s Alakfelismer{\H o}k T{\'a}rsas{\'a}g{\'a}nak konferenci{\'a}ja - K{\'E}PAF 2013}, year = {2013}, month = {Jan 2013}, pages = {210 - 223}, publisher = {NJSZT-K{\'E}PAF}, organization = {NJSZT-K{\'E}PAF}, type = {Conference paper}, address = {Veszpr{\'e}m}, author = {L{\'a}szl{\'o} G{\'a}bor Varga and P{\'e}ter Bal{\'a}zs and Antal Nagy}, editor = {L{\'a}szl{\'o} Cz{\'u}ni} } @inbook {1151, title = {Local uncertainty in binary tomographic reconstruction}, booktitle = {Proceedings of the IASTED International Conference on Signal Processing, Pattern Recognition and Applications (SPPRA 2013)}, year = {2013}, note = {ScopusID: 84876584488doi: 10.2316/P.2013.798-067}, month = {Feb 2013}, pages = {490 - 496}, publisher = {IASTED - Acta Press}, organization = {IASTED - Acta Press}, type = {Conference paper}, address = {Calgary}, abstract = {

We describe a new approach for the uncertainty problem arisingin the field of discrete tomography, when the low number of projections does not hold enough information for an accurate, and reliable reconstruction. In this case the lack of information results in uncertain parts on the reconstructed image which are not determined by the projections and cannot be reliably reconstructed without additional information. We provide a method that can approximate this local uncertainty of reconstructions, and show how each pixel of the reconstructed image is determined by a set of given projections. We also give experimental results for validating our approach.

}, doi = {10.2316/P.2013.798-067}, author = {L{\'a}szl{\'o} G{\'a}bor Varga and L{\'a}szl{\'o} G{\'a}bor Ny{\'u}l and Antal Nagy and P{\'e}ter Bal{\'a}zs}, editor = {Martin Kampel} } @inbook {1149, title = {An energy minimization reconstruction algorithm for multivalued discrete tomography}, booktitle = {Computational Modelling of Objects Represented in Images: Fundamentals, Methods and Applications III}, year = {2012}, month = {2012}, pages = {179 - 185}, publisher = {CRC Press - Taylor and Frances Group}, organization = {CRC Press - Taylor and Frances Group}, type = {Conference paper}, address = {London}, abstract = {

We propose a new algorithm for multivalued discrete tomography, that reconstructs images from few projections by approximating the minimum of a suitably constructed energy function with a deterministic optimization method. We also compare the proposed algorithm to other reconstruction techniques on software phantom images, in order to prove its applicability.

}, doi = {10.1201/b12753-1}, author = {L{\'a}szl{\'o} G{\'a}bor Varga and P{\'e}ter Bal{\'a}zs and Antal Nagy}, editor = {Paolo Di Giamberardino and Daniela Iacoviello and Renato M Natal Jorge and Joao Manuel R S Taveres} } @article {1148, title = {A novel optimization-based reconstruction algorithm for multivalued discrete tomography}, year = {2012}, month = {June 2012}, pages = {57}, publisher = {University of Szeged, Institute of Informatics}, type = {Abstract}, address = {Szeged}, author = {L{\'a}szl{\'o} G{\'a}bor Varga and P{\'e}ter Bal{\'a}zs and Antal Nagy} } @conference {1155, title = {An optimization-based reconstruction algorithm for multivalued discrete tomography}, booktitle = {Veszpr{\'e}m Optimization Conference: Advanced Algorithms (Vocal)}, year = {2012}, month = {Dec 2012}, pages = {39 - 40}, publisher = {University of Pannonia}, organization = {University of Pannonia}, type = {Conference paper}, address = {Veszpr{\'e}m}, author = {L{\'a}szl{\'o} G{\'a}bor Varga and P{\'e}ter Bal{\'a}zs and Antal Nagy} } @article {1127, title = {Direction-dependency of binary tomographic reconstruction algorithms}, journal = {GRAPHICAL MODELS}, volume = {73}, year = {2011}, note = {UT: 000296999100028ScopusID: 80054709026doi: 10.1016/j.gmod.2011.06.006}, month = {Nov 2011}, pages = {365 - 375}, type = {Journal article}, abstract = {

In this work we study the relation between the quality of a binary tomographic reconstruction and the choice of angles of the projections. We conduct experiments on a set of software phantoms by reconstructing them from different projection sets using three different discrete tomography reconstruction algorithms, and compare the accuracy of the corresponding reconstructions with suitable approaches. To validate our results for possible real-world applications, we conduct the experiments by adding random noise of different characteristics to the simulated projection data, and by applying small topological changes on the phantom images as well. In addition, we also discuss some consequences of the angle-selection dependency and possible practical applications arising from the field of non-destructive testing, too.

}, isbn = {1524-0703}, doi = {10.1016/j.gmod.2011.06.006}, author = {L{\'a}szl{\'o} G{\'a}bor Varga and P{\'e}ter Bal{\'a}zs and Antal Nagy} } @article {1334, title = {Projection selection dependency in binary tomography}, journal = {ACTA CYBERNETICA-SZEGED}, volume = {20}, year = {2011}, note = {ScopusID: 79960679541}, month = {2011}, pages = {167 - 187}, publisher = {University of Szeged, Institute of Informatics}, type = {Journal article}, address = {Szeged}, abstract = {

It has already been shown that the choice of projection angles can significantly influence the quality of reconstructions in discrete tomography. In this contribution we summarize and extend the previous results by explaining and demonstrating tile effects of projection selection dependency, in a set of experimental software tests. We perform reconstructions of software phantoms, by using different binary tomography reconstruction algorithms, from different equiangular and non-equiangular projections sets, under various conditions (i.e., when the objects to be reconstructed undergo slight topological changes, or the projection data is affected by noise) and compare the results with suitable approaches. Based on our observations, we reveal regularities in the resulting data and discuss possible consequences of such projection selection dependency in binary tomography.

}, isbn = {0324-721X}, author = {L{\'a}szl{\'o} G{\'a}bor Varga and P{\'e}ter Bal{\'a}zs and Antal Nagy} } @conference {1130, title = {Vet{\"u}leti ir{\'a}nyf{\"u}gg{\H o}s{\'e}g a bin{\'a}ris tomogr{\'a}fi{\'a}ban}, booktitle = {A K{\'e}pfeldolgoz{\'o}k {\'e}s Alakfelismer{\H o}k T{\'a}rsas{\'a}g{\'a}nak konferenci{\'a}ja - K{\'E}PAF 2011}, year = {2011}, month = {Jan 2011}, pages = {92 - 105}, publisher = {NJSZT}, organization = {NJSZT}, type = {Conference paper}, address = {Szeged}, author = {L{\'a}szl{\'o} G{\'a}bor Varga and P{\'e}ter Bal{\'a}zs and Antal Nagy}, editor = {Zoltan Kato and K{\'a}lm{\'a}n Pal{\'a}gyi} } @inbook {1110, title = {Direction-dependency of a binary tomographic reconstruction algorithm}, booktitle = {Computational Modeling of Objects Represented in Images}, series = {Lecture Notes in Computer Science}, number = {6026}, year = {2010}, note = {UT: 000279020400022ScopusID: 77952365308doi: 10.1007/978-3-642-12712-0_22}, month = {May 2010}, pages = {242 - 253}, publisher = {Springer Verlag}, organization = {Springer Verlag}, type = {Conference paper}, address = {Buffalo, NY, USA}, abstract = {

We study how the quality of an image reconstructed by a binary tomographic algorithm depends on the direction of the observed object in the scanner, if only a few projections are available. To do so we conduct experiments on a set of software phantoms by reconstructing them form different projection sets using an algorithm based on D.C. programming (a method for minimizing the difference of convex functions), and compare the accuracy of the corresponding reconstructions by two suitable approaches. Based on the experiments, we discuss consequences on applications arising from the field of non-destructive testing, as well.

}, isbn = {978-3-642-12711-3}, doi = {10.1007/978-3-642-12712-0_22}, author = {L{\'a}szl{\'o} G{\'a}bor Varga and P{\'e}ter Bal{\'a}zs and Antal Nagy}, editor = {Reneta P Barneva and Valentin E Brimkov and Herbert A Hauptman and Renato M Natal Jorge and Jo{\~a}o Manuel R S Tavares} } @conference {1124, title = {Object rotation effects on binary tomographic reconstruction}, booktitle = {Conference of PhD Students in Computer Science. Volume of Extended Abstracts}, year = {2010}, month = {June 2010}, pages = {76}, publisher = {University of Szeged}, organization = {University of Szeged}, type = {Abstract}, address = {Szeged, Hungary}, author = {L{\'a}szl{\'o} G{\'a}bor Varga and P{\'e}ter Bal{\'a}zs and Antal Nagy} } @inbook {1333, title = {Projection selection algorithms for discrete tomography}, booktitle = {Advanced Concepts for Intelligent Vision Systems}, year = {2010}, note = {UT: 000287941400037ScopusID: 78650892305doi: 10.1007/978-3-642-17688-3_37}, month = {Dec 2010}, pages = {390 - 401}, publisher = {Springer Verlag}, organization = {Springer Verlag}, type = {Conference paper}, address = {Sydney, Australia }, author = {L{\'a}szl{\'o} G{\'a}bor Varga and P{\'e}ter Bal{\'a}zs and Antal Nagy}, editor = {Jacques Blanc-Talon and Don Bone and Wilfried Philips and Dan Popescu and Paul Scheunders} }