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Budapest, Hungary

Domonkos B.,Mediso Medical Imaging Systems | Csebfalvi B.,Budapest University of Technology and Economics
VMV 2010 - Vision, Modeling and Visualization | Year: 2010

In this paper, we thoroughly study a trilinear interpolation scheme previously proposed for the Body-Centered Cubic (BCC) lattice. We think that, up to now, this technique has not received the attention that it deserves. By a frequency-domain analysis we show that it can isotropically suppress those aliasing spectra that contribute most to the postaliasing effect. Furthermore, we present an efficient GPU implementation, which requires only six trilinear texture fetches per sample. Overall, we demonstrate that the trilinear interpolation on the BCC lattice is competitive to the linear box-spline interpolation in terms of both efficiency and image quality. As a generalization to higher-order reconstruction, we introduce DC-splines that are constructed by convolving a Discrete filter with a Continuous filter, and easy to adapt to the Face-Centered Cubic (FCC) lattice as well. © The Eurographics Association 2010. Source

Domonkos B.,Mediso Medical Imaging Systems | Csebfalvi B.,Budapest University of Technology and Economics
Journal of WSCG | Year: 2011

The major preference for applying B-spline filtering rather than non-separable box spline filtering on the BCC lattice is the fact that separable filtering can be performed more efficiently on current GPUs due to the utilization of the hardware-accelerated trilinear texture fetching. In order to make a fair comparison, a similar, efficient evaluation scheme is required that uses trilinear texture fetches instead of nearest-neighbor ones also for the box splines. Thus, in this paper, we propose an evaluation scheme for the linear BCC box spline built upon a trilinear B-spline basis. We compare our trilinearly evaluated linear box spline scheme to the latest method, that uses twice as many nearest neighbor fetches. Then we give a comparison to the major competitive methods: the BCC B-spline filtering and the BCC DC-spline filtering in terms of their performance. Source

Csebfalvi B.,Budapest University of Technology and Economics | Domonkos B.,Mediso Medical Imaging Systems
Proceedings - SCCG 2010: 26th Spring Conference on Computer Graphics | Year: 2010

Recently, it has been demonstrated that the optimality of the Body-Centered Cubic (BCC) lattice can be utilized also in practice by using either non-separable box-spline filters or tensor-product Bspline filters for reconstructing an originally continuous signal from its discrete BCC-sampled representation. In order to study the frequency-domain behavior of these filters, a 3D analysis of their frequency responses is required. In this paper, we show that direct volume rendering offers a natural tool for such a 3D analysis. As the frequency responses are analytically known, their characteristic isosurfaces can be rendered separately in the pass band and in the stop band. The visualization of the frequency responses conveys information not just on the absolute postaliasing and oversmoothing effects, but also on their direction dependence. In this sense, the frequency-domain behavior of the non-separable box splines and the tensor-product B-splines on the BCC lattice is evaluated for the first time in this paper. Furthermore, we also analyze how the frequency responses are influenced by a discrete prefiltering, which is necessary to fully exploit the approximation power of the higher-order box-spline and B-spline filters. Copyright © 2010 by the Association for Computing Machinery, Inc. Source

Papp L.,Mediso Medical Imaging Systems | Juhasz R.,University of Szeged | Travar S.,University of Novi Sad | Kolli A.,Medical University of Graz | Sorantin E.,Medical University of Graz
Journal of X-Ray Science and Technology | Year: 2010

Funnel chest (Pectus excavatum) is the most common deformity of the anterior chest in children. Present paper describes a method to process and classify CT slices representing funnel chest deformities. A manually chosen CT slice was processed to detect the inner curvature of the chest for characterization. Normalized data from the detected inner curvature was gained and saved next to a manually-given deformity type for further classification rule determinations. Based on the multiple correlations of the values gained from the inner curvature, a hierarchical classification was performed on 199 patient data. Results have shown that the calculated values gained from the inner curvature can accurately characterize the deformity type of the chest. Since minimal user interaction was necessary to detect and characterize the inner curvature, our method is considered to be an effective automated procedure for funnel chest deformity classifications. © 2010-IOS Press and the authors. Source

Busca P.,Polytechnic of Milan | Busca P.,National Institute of Nuclear Physics, Italy | Fiorini C.,Polytechnic of Milan | Fiorini C.,National Institute of Nuclear Physics, Italy | And 17 more authors.
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2014

A new multi-modality imaging tool is under development in the framework of the INSERT (INtegrated SPECT/MRI for Enhanced Stratification in Radio-chemo Therapy) project, supported by the European Community. The final goal is to develop a custom SPECT apparatus, that can be used as an insert for commercially available MRI systems such as 3 T MRI with 59 cm bore diameter. INSERT is expected to offer more effective and earlier diagnosis with potentially better outcome in survival for the treatment of brain tumors, primarily glioma. Two SPECT prototypes will be developed, one dedicated to preclinical imaging, the second one dedicated to clinical imaging. The basic building block of the SPECT detector ring is a small 5 cm×5 cm gamma camera, based on the well-established Anger architecture with a continuous scintillator readout by an array of silicon photodetectors. Silicon Drift Detectors (SDDs) and Silicon PhotoMultipliers (SiPM) are being considered as possible scintillator readout, considering that the detector choice plays a predominant role for the final performance of the system, such as energy and spatial resolution, as well as the useful field of view of the camera. Both solutions are therefore under study to evaluate their performances in terms of field of view (FOV), spatial and energy resolution. Preliminary simulations for both the preclinical and clinical systems have been carried out to evaluate resolution and sensitivity. © 2013 Elsevier B.V. All rights reserved. Source

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