Inspired by binary tomography, we present a measure of directional convexity of binary images combining various properties of the configuration of 0s and 1s in the binary image. The measure can be supported by proper theory, is easy to compute, and as shown in our experiments, behaves intuitively. The measure can be useful in numerous applications of digital image processing and pattern recognition, and especially in binary tomography. We show in detail an application of this latter one, by providing a novel reconstruction algorithm for almost hv-convex binary images. We also present experimental results and mention some of the possible generalizations of the measure.

%B Fundamenta Informaticae %V 141 %P 151-167 %8 Oct 2015 %G eng %N 2-3 %9 Journal article %& 151 %R 10.3233/FI-2015-1269 %0 Generic %D 2014 %T Reconstruction of hv-convex binary matrices from horizontal and vertical projections based on simulated annealing %A Zoltán Ozsvár %A Péter Balázs %B Proceedings of the 9th Conference of PhD Students in Computer Science (CSCS'14) %I University of Szeged %C Szeged, Hungary %P 50 %G eng %9 Abstract %0 Conference Paper %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2013 %D 2013 %T A comparison of heuristics for reconstructing hv-convex binary matrices from horizontal and vertical projections %A Zoltán Ozsvár %A Péter Balázs %E László Czúni %B A Képfeldolgozók és Alakfelismerők Társaságának konferenciája - KÉPAF 2013 %I NJSZT-KÉPAF %C Veszprém %P 168 - 181 %8 Jan 2013 %G eng %9 Conference paper %0 Journal Article %J ACTA CYBERNETICA-SZEGED %D 2013 %T An empirical study of reconstructing hv-convex binary matrices from horizontal and vertical projections %A Zoltán Ozsvár %A Péter Balázs %XThe reconstruction of hv-convex binary matrices (or equivalently, binary images) from their horizontal and vertical projections is proved to be NP-hard. In this paper we take a closer look at the difficulty of the problem. We investigate different heuristic reconstruction algorithms of the class, and compare them from the viewpoint of running-time and reconstruction quality. Using a large set of test images of different sizes and with varying number of components, we show that the reconstruction quality can depend not only on the size of the image, but on the number and location of its components, too. We also reveal that the reconstruction time can also be affected by the number of the so-called switching components present in the image.

%B ACTA CYBERNETICA-SZEGED %V 21 %P 149 - 163 %8 2013 %@ 0324-721X %G eng %9 Journal article %! ACTA CYBERN-SZEGED %0 Generic %D 2012 %T Empirical studies of reconstructing hv-convex binary matrices from horizontal and vertical projections %A Zoltán Ozsvár %A Péter Balázs %B Conference of PhD students in computer science. Volume of Extended Abstracts. %I University of Szeged, Institute of Informatics %C Szeged %P 44 %8 June 2012 %G eng %9 Abstract