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Fast heuristics for eliminating switching components in binary matrices by 0-1 flips 19

19th Iberoamerican Congress on Pattern Recognition, CIARP 2014

作者： Hantos, Norbert Balázs, Péter Department of Image Processing and Computer Graphics University of Szeged Árpád tér 2 SzegedH-6720 Hungary

ISBN: (纸本)9783319125671

Switching components are special patterns in binary matrices that play an essential role in many image processing and pattern analysis tasks. Finding the minimal number of 0s that must be switched to 1s in order to eliminate all switching components is an NP-complete problem. We present two novel-type heuristics for the above problems and show via experiments that they outperform the formerly proposed ones, both in optimality and in running time. © Springer International Publishing Switzerland 2014.

关键词： image reconstruction

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Fourier Domain CT Reconstruction with Complex Valued Neural Networks 3rd

Fourier Domain CT Reconstruction with Complex Valued Neural...

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3rd International Conference on Pattern Recognition and Artificial Intelligence, ICPRAI 2022

作者： Domokos, Zoltán Varga, László G. Department of Image Processing and Computer Graphics University of Szeged Árpád tér 2. Szeged6720 Hungary

ISBN: (纸本)9783031090363

In computed tomography, several well-known techniques exist that can reconstruct a cross section of an object from a finite set of it’s projections, the sinogram. This task – the numerical inversion of the Radon transform – is well understood, with state of the art algorithms mostly relying on back-projection. Even though back-projection has a significant computational burden compared to the family of direct Fourier reconstruction based methods, the latter class of algorithms is less popular due to the complications related to frequency space resampling. Moreover, interpolation errors in resampling in frequency domain can lead to artifacts in the reconstructed image. Here, we present a novel neural-network assisted reconstruction method, that intends to reconstruct the object in frequency space, while taking the well-understood Fourier slice theorem into account as well. In our case, the details of approximated resampling is learned by the network for peak performance. We show that with this method it is possible to achieve comparable, and in some cases better reconstruction quality than with another state of the art algorithm also working in frequency domain. © 2022, Springer Nature Switzerland AG.

关键词： Neural networks

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Assessment of the Effects of an Unrecultivated Sewage Disposal Site on GroundWater 2020

Assessment of the Effects of an Unrecultivated Sewage Dispos...

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4th International Conference on Geo-IT and Geospatial Technologies and Water Resources in Mediterranean Region, GEOIT4W 2020

作者： Mester, Tamás Szabó, György Balla, Dániel Department of Landscape Protection and Environmental Geography University of Debrecen Debrecen Hungary Department of Computer Graphics and Image Processing University of Debrecen Debrecen Hungary

ISBN: (纸本)9781450375788

The aim of this study was to investigate the environmental effects of a sewage disposal site operating between 1994 and 2010. After the end of operation, the disposal site was abandoned without recultivation. In order to determine the shallow groundwater contamination of the area, monitoring wells in the wastewater infiltration basin and in its vicinity were established. The texture of the soil in the area was determined. In addition, the NO3-N, PO43-, OC, CaCO3, OC content and pH of the soil (at every 20 cm to a depth of 5 meters) was determined in the well section of the infiltration basin, which was considered the most polluted area. The NH4+, NO2-, NO3-, COD content of the groundwater samples were determined. The results of our examination revealed significant contamination of the area. The leachate nitrate profile is clearly visible in the soil, with a maximum of 3706 mg/Kg-1 at a depth of 120-140 cm. The phosphate content of the soil was above 1900 mg/Kg-1 in the upper 40 cm. The organic matter content of the water samples in the infiltration basin was 98.4 mg/L-1, that approximates to the typical amount of municipal wastewater. In the most polluted area ammonium was measured at 78 mg/L-1, and concentrations in the majority of monitoring wells were above the contamination limit of 0.5 mg/L-1. The highest nitrate value was 393 mg/L-1, significantly above the 50 mg/L-1 contamination limit. Our results show that the sewage disposal site and its environment is heavily contaminated. It is therefore highly recommended to recultivate the disposal site. © 2020 ACM.

关键词： Textures

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A Comprehensive Investigation of Climate Change Strategies in the Mediterranean Region 2020

A Comprehensive Investigation of Climate Change Strategies i...

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4th International Conference on Geo-IT and Geospatial Technologies and Water Resources in Mediterranean Region, GEOIT4W 2020

作者： Kiss, Emőke Fazekas, István Zichar, Marianna Balla, Dániel Department of Landscape Protection and Environmental Geography University of Debrecen Debrecen Hungary Department of Computer Graphics and Image Processing University of Debrecen Debrecen Hungary

ISBN: (纸本)9781450375788

According to the five Intergovernmental Panel on Climate Change (IPCC) Assessment Reports published between 1990 and 2014, changes in the climate have had varying impacts on both society and natural systems. Climate change strategies have been created to reduce greenhouse gas emissions and adapt to the unavoidable impacts of climate change. During research, we investigated climate change strategies in 21 Mediterranean countries (Albania, Algeria, Bosnia and Herzegovina, Croatia, Cyprus, Egypt, France, Greece, Israel, Italy, Lebanon, Libya, Malta, Monaco, Montenegro, Morocco, Slovenia, Spain, Syria, Tunisia, and Turkey). There is no unequivocal delineation of the Mediterranean region, so countries were selected, which are surrounded by the Mediterranean Sea. Considering the available documents by spatial area and by category, in 7 countries (i.e. in 33.3% of the countries) no strategy can be found, in 4 countries (19%) a combined adaptation + mitigation category can be found, in 4 countries (19%) a complex category, in 2 countries (9.5%) we find mitigation and in 2 further countries a combined adaptation + mitigation + complex category (9.5%). The adaptation and the adaptation + complex categories are found in one country each (4.7%). According to World Bank Population data (2017), 506.2 million people live in these 21 countries, and 49.8 million people live in a country which has no climate change documents at all. © 2020 ACM.

关键词： Climate change

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Barcode detection with morphological operations and clustering

Barcode detection with morphological operations and clusteri...

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IASTED International Conference on Signal processing, Pattern Recognition and Applications, SPPRA 2012

作者： Bodnár, Péter Nyúl, László G. Department of Image Processing and Computer Graphics University of Szeged Árpád tér 2. Szeged H-6720 Hungary

ISBN: (纸本)9780889869219

Barcode detection has many applications and detection methods. Each application has its own requirements for speed and detection accuracy. Fine-tuning, upgrading or combining existing methods gives fast and robust solutions for detection. Modern computer vision techniques help the whole process to be fully automated. Different detection approaches are examined in this paper, and new methods are introduced.

关键词： Feature extraction

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Complexity results for reconstructing binary images with disjoint components from horizontal and vertical projections

Complexity results for reconstructing binary images with dis...

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作者： Balázs, Péter Department of Image Processing and Computer Graphics University of Szeged Árpád tér 2. H-6720 Szeged Hungary

The problem of reconstructing a special class of binary images from their horizontal and vertical projections is considered. We present a general framework for analyzing the worst case complexity of this task if the image consists of more than one pairwise disjoint component. Applying the presented technique we analyze the complexity of reconstructing canonical hv-convex binary images. We also present parameterized complexity results on general and so-called glued hv-convex images. Moreover, we study how our results are related to the reconstruction of permutation matrices from four projections. © 2012 Elsevier B.V. All rights reserved.

关键词： Binary images

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Analytic Web Tool for Calculating and Geovisualizing Water Quality Based on Different Indices 2020

Analytic Web Tool for Calculating and Geovisualizing Water Q...

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4th International Conference on Geo-IT and Geospatial Technologies and Water Resources in Mediterranean Region, GEOIT4W 2020

作者： Balla, Dániel Zichar, Marianna Kiss, Emőke Karancsi, Gergő Mester, Tamás Department of Computer Graphics and Image Processing University of Debrecen Debrecen Hungary Department of Landscape Protection and Environmental Geography University of Debrecen Debrecen Hungary

ISBN: (纸本)9781450375788

In the present study, the effects of sewage network construction on groundwater quality are evaluated using Backman's contamination index (Cd) and the Water Quality Index (WQI). For this assessment we developed a freely available interactive web tool which was used to quantify the groundwater quality status of the investigated wells. It can also be used to publish the uploaded spatial data to a webmap. Using this application, we detected the potentially contaminated areas and were able to compare the different indices. Water samples were collected from 40 groundwater wells in the summer of 2019. The groundwater quality was assessed by using the water quality status and contamination degree methods. The degree of contamination of the groundwater was classified into 5 categories: Cd>3 very high contamination, 3>Cd>2 high contamination, 2>Cd> 1 moderate contamination, 1>Cd low contamination, and Cd=0 non-contaminated. The results show moderately high groundwater contamination. In 2019, in 52.5% of the examined wells, the water quality was very highly or highly contaminated. Only 10% of the water samples had a low degree of contamination and one sample was ***@The Water Quality Status (WQS) of the monitoring wells was determined according to the WQI values. In 2019 37.5% of the water samples were categorized as being in the poor (51 © 2020 ACM.

关键词： Water quality

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On the ambiguity of reconstructing hv-convex binary matrices with decomposable configurations

On the ambiguity of reconstructing hv-convex binary matrices...

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作者： Balázs, Péter Department of Image Processing and Computer Graphics University of Szeged Árpád tér 2 6720 Szeged Hungary

Reconstructing binary matrices from their row, column, diagonal, and antidiagonal sums (also called projections) plays a central role in discrete to-mography. One of the main difficulties in this task is that in certain cases the projections do not uniquely determine the binary matrix. This can yield an extremely large number of (sometimes very different) solutions. This ambiguity can be reduced by having some prior knowledge about the matrix to be reconstructed. The main challenge here is to find classes of binary matrices where ambiguity is drastically reduced or even completely eliminated. The goal of this paper is to study the class of hv-convex matrices which have decomposable configurations from the viewpoint of ambiguity. First, we give a negative result in the case of three projections. Then, we present a heuristic for the reconstruction using four projections and analyze its performance in quality and running time.

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Geometric parameters based cubic PH curve interpolation and approximation

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Journal of Information and Computational Science 2009年第6期6卷 2423-2432页

作者： Cheng, Min Wang, Guojin Department of Mathematics Zhejiang University Zhejiang Hangzhou 310000 China College of Science Zhejiang University of Technology Zhejiang Hangzhou 310000 China Institute of Computer Graphics and Image Processing Zhejiang University Zhejiang Hangzhou 310000 China

The Pythagorean-hodograph curves offer unique computational advantages in computer aided design and manufacturing. In this paper, geometric parameters based cubic PH curve interpolation and approximation algorithms are presented. The essential geometric parameters include the ratio ρ of the adjacent control polygon legs, the control polygon angle θ, the first control polygon leg L, the included angle δ between the first control polygon edge and the edge joining the origin O and the first control point, as well as the coefficient Dir of curve rotation. Furthermore the problem of PH curve approximation with endpoints interpolation to a cubic non-PH curve is studied, including the algorithms based on different geometric parameters input {δ, θ}, {ρ, θ} and {ρ, δ} respectively. © 2009 Binary Information Press.

关键词： Approximation algorithms

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Extended Cubic Uniform B-spline and α-B-spline

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自动化学报 2008年第8期34卷 980-983页

作者： XU Gang WANG Guo-Zhao Institute of Computer Graphics and Image Processing Department of Mathematics Zhejiang University Hangzhou 310027 P. R. China

花键曲线和表面在 CAD 和计算机图形起一个重要作用。在这份报纸，我们建议立方的一致 B 花键的几延期。然后，我们在场插入内推的延期 -B-spline 基于新 B 花键和单个相配技术。延期的优点是他们有全球、本地的形状参数。而且，我们也... 详细信息

花键曲线和表面在 CAD 和计算机图形起一个重要作用。在这份报纸，我们建议立方的一致 B 花键的几延期。然后，我们在场插入内推的延期 -B-spline 基于新 B 花键和单个相配技术。延期的优点是他们有全球、本地的形状参数。而且，我们也在数据插值和多角形的形状变丑调查他们的应用。

关键词：计算机技术 CAD 图象处理技术几何图形

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