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Characterisation of human non-proliferative diabetic retinopathy using the fractal analysis

International Journal of Ophthalmology(English edition) 2015年第4期8卷 770-776页

作者： Stefan Tǎlu Dan Mihai Cǎlugǎru Carmen Alina Lupascu Discipline of Descriptive Geometry and Engineering Graphics Department of AET Faculty of Mechanical Engineering Technical University of Cluj-Napoca Discipline of Ophthalmology Department of Surgical Specialties and Medical Imaging Faculty of Medicine Iuliu Hatieganu University of Medicine and Pharmacy Cluj-Napoca Department of Mathematics and Informatics University of Palermo

· AIM: To investigate and quantify changes in the branching patterns of the retina vascular network in diabetes using the fractal analysis method.·METHODS: This was a clinic-based prospective study of 172 participants managed at the Ophthalmological Clinic of Cluj-Napoca, Romania, between January 2012 and December 2013. A set of 172 segmented and skeletonized human retinal images, corresponding to both normal(24 images) and pathological(148 images)states of the retina were examined. An automatic unsupervised method for retinal vessel segmentation was applied before fractal analysis. The fractal analyses of the retinal digital images were performed using the fractal analysis software Image J. Statistical analyses were performed for these groups using Microsoft Office Excel2003 and Graph Pad In Stat software.·RESULTS: It was found that subtle changes in the vascular network geometry of the human retina are influenced by diabetic retinopathy(DR) and can be estimated using the fractal geometry. The average of fractal dimensions D for the normal images(segmented and skeletonized versions) is slightly lower than the corresponding values of mild non-proliferative DR(NPDR) images(segmented and skeletonized versions).The average of fractal dimensions D for the normal images(segmented and skeletonized versions) is higher than the corresponding values of moderate NPDR images(segmented and skeletonized versions). The lowestvalues were found for the corresponding values of severe NPDR images(segmented and skeletonized versions).· CONCLUSION: The fractal analysis of fundus photographs may be used for a more complete understanding of the early and basic pathophysiological mechanisms of diabetes. The architecture of the retinal microvasculature in diabetes can be quantitative quantified by means of the fractal *** abnormalities on retinal imaging may elucidate early mechanistic pathways for microvascular complications and distinguish patients with DR from health

关键词： diabetic retinopathy fractal fractal dimension retinal image analysis retinal microvasculature

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Characterization of human retinal vessel arborisation in normal and amblyopic eyes using multifractal analysis

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International Journal of Ophthalmology(English edition) 2015年第5期8卷 996-1002页

作者： Stefan Tǎlu Cristina Vlǎdutiu Carmen A.Lupascu Discipline of Descriptive Geometry and Engineering Graphics Department of Automotive Engineering and TransportationFaculty of Mechanical EngineeringTechnical University of Cluj-Napoca Discipline of Ophthalmology Department of Surgical Specialties and Medical ImagingFaculty of Medicine"Iuliu Hatieganu" University of Medicine and Pharmacy Cluj-Napoca Department of Mathematics and Informatics University of Palermo

AIMTo characterize the human retinal vessel arborisation in normal and amblyopic eyes using multifractal geometry and lacunarity *** analysis using a box counting algorithm was carried out for a set of 12 segmented and skeletonized human retinal images, corresponding to both normal (6 images) and amblyopia states of the retina (6 images).RESULTSIt was found that the microvascular geometry of the human retina network represents geometrical multifractals, characterized through subsets of regions having different scaling properties that are not evident in the fractal analysis. Multifractal analysis of the amblyopia images (segmented and skeletonized versions) show a higher average of the generalized dimensions (D_q) for q=0, 1, 2 indicating a higher degree of the tree-dimensional complexity associated with the human retinal microvasculature network whereas images of healthy subjects show a lower value of generalized dimensions indicating normal complexity of biostructure. On the other hand, the lacunarity analysis of the amblyopia images (segmented and skeletonized versions) show a lower average of the lacunarity parameter Λ than the corresponding values for normal images (segmented and skeletonized versions).CONCLUSIONThe multifractal and lacunarity analysis may be used as a non-invasive predictive complementary tool to distinguish amblyopic subjects from healthy subjects and hence this technique could be used for an early diagnosis of patients with amblyopia.

关键词： retina retinal vessels amblyopia strabismus multifractals lacunarity

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Numerical Modeling of Local Penetration of Chloride-Containing Medium into Construction Elements Made of Reinforced Concrete

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IOP Conference Series: Materials Science and Engineering 2017年第1期262卷

作者： I I Ovchinnikov O V Snezhkina I G Ovchinnikov Department of Transport construction Yuri Gagarin State Technical University of Saratov 77 Polytechnic str. Saratov 410054 Russia Department of descriptive geometry and graphics Penza State University of Architecture and Construction 28 Herman Titov Street Penza 440028 Russia Department of Automobile roads and bridges Perm National Research Polytechnic University 29 Komsomolsky prospect Perm 614990 Russia

The task of modeling the kinetics of chloride-containing medium penetration into construction elements out of reinforced concrete that have partially damaged anti-corrosion protective coatings is being discussed. As a result, chlorides penetrate the construction element via local surface areas which leads to irregularities between chloride dispersion volumes. The kinetics of chloride penetration is described by the equation of diffusion to solve which the CONDUCT software complex by professor S. Patankar was used. The methodology used to solve the diffusional equation is described. The results of the evaluation of concentration field in the axial section of a cylindrical construction element, which was centrally reinforced, are given. The chloride diffusion was symmetrical to the axis, the medium was applied through the central ring area equal to one third of the side surface area while the rest of the surface was isolated. It was shown that the methodology of evaluation and its algorithm allow one to evaluate the concentration field of chlorides in reinforced concrete structural elements under local or asymmetrical action of the chloride - containing medium. The example given illustrates that after a certain time interval critical the concentration of chlorides develops even in protected areas which are located far from the initial damaged area. This means that the corrosion destruction of reinforced elements develops not only in the immediate damage area, but also further away from it.

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Micromorphological characterization of polymer-oxide nanocomposite thin films by atomic force microscopy and fractal geometry analysis

Micromorphological characterization of polymer-oxide nanocom...

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作者： Ţəlu, Ştefan Patra, Niranjan Salerno, Marco Technical University of Cluj-Napoca Faculty of Mechanical Engineering Department of AET Discipline of Descriptive Geometry and Engineering Graphics 103-105 B-dul Muncii St. Cluj-Napoca Cluj400641 Romania Istituto Italiano di Tecnologia Nanophysics Department Scanning Probe Microscopy Lab via Morego 30 GenovaI-16163 Italy Imperial College Faculty of Engineering Department of Materials LondonSW7 2AZ United Kingdom

The purpose of this study was to evaluate the 3-D surface micromorphology of polymer-oxide thin films spin-coated from a composite of poly-methyl-methacrylate as the matrix and elongated titania nanorods as the filler particles. The surfaces of these composite films were investigated by atomic force microscopy and characterized by fractal geometry analysis. The effect of increasing loading of the fillers between 0 and 30% by weigth relative to the matrix was assessed. An increasing roughness was observed, with typical emergence of protruding ripples progressively extending into larger stripes. The amplitude parameters of the surfaces were determined by analysis of the height distributions. The fractal analysis of roughness revealed that the films have fractal geometry. Triangulation method based on the linear interpolation type was applied to determine the fractal dimension. A connection was observed between the surface morphology and the physical properties of the coatings as assessed in previous works. © 2015 Elsevier B.V. All rights reserved.

关键词： Atomic force microscopy

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A method of identification of image fragments on the basis of multiresponse statistical models

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Pattern Recognition and Image Analysis 2014年第3期24卷 457-462页

作者： Popov, S.A. Naumov, A.S. Emel’yanov, G.M. Section of Descriptive Geometry and Computer Graphics Yaroslav-the-Wise Novgorod State University ul. B.S. Peterburgskaya 41 Veliky Novgorod173003 Russia Department of Information Technologies and Systems Yaroslav-the-Wise Novgorod State University ul. B.S. Peterburgskaya 41 Veliky Novgorod173003 Russia

This paper proposes a method for identifying image fragments presented by a multiresponse piecewise-linear model of segments and corner points, which considers the geometric and color contour. The method can improve the accuracy of identification of fragments and the subsequent reconstruction of a fragmented image. © 2014, Pleiades Publishing, Ltd.

关键词： Piecewise linear techniques

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Automatic extraction of salient objects in 3D stereoscopic videos

Automatic extraction of salient objects in 3D stereoscopic v...

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International Symposium on Electronics and Telecommunications (ISETC)

作者： Ruxandra Tapu Bogdan Mocanu Ermina Tapu Department of Telecommunications University “Politehnica” of Bucharest Bucharest Romania Dept. of Descriptive Geometry and Engineering Graphics University “Politehnica” of Bucharest Romania

For 3D stereoscopic videos the depth perception represents an important factor that affects the human visual attention much more than any motion or texture contrast existent in a traditional 2D videos. In this context, the present paper addressed the issue of stereoscopic visual attention models designed to detect salient objects in 3D videos. We propose representing the image sequence as a 2D video stream and its associated depth maps. The technique starts by combining a spatiotemporal attention model with a disparity map. The depth map offers important information about the objects position in space and helps us estimating their relative distance to the video camera. The proposed method is evaluated on a set of ten 3D video streams and can be considered efficient and robust.

关键词： Videos Visualization Three-dimensional displays Spatiotemporal phenomena Stereo image processing Streaming media Cameras

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Project method as a professional competence forming factor for the geometro-graphic training of future engineers

Project method as a professional competence forming factor f...

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2012 15th International Conference on Interactive Collaborative Learning, ICL 2012

作者： Vereshchagina, Tatiana Department Design Graphics and Descriptive Geometry Perm National Research Polytechnic University Perm Russia

ISBN: (纸本)9781467324274

In this paper it is told about integration relations between subject «descriptive geometry. Engineering graphics», and an engineering specialization. Integration can be achieved in the process of individual and collective working with projects in the solution of engineering problems that are related to pupils' future profession. © 2012 IEEE.

关键词： Integration

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Salient object detection in video streams

Salient object detection in video streams

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International Symposium on Electronics and Telecommunications (ISETC)

In this paper we propose a complete framework for automatic detection and tracking of salient objects in video streams. The video flow is firstly segmented into shots based on scale space filtering graph partition method. For each detected shot the associated static summary is developed using a leap keyframe extraction method. Based on the representative images we introduce next a combined spatial and temporal video attention model that is able to recognize both interesting objects and actions in image sequences. The approach extends the state-of-the-art image region based contrast saliency with a temporal attention model. Different types of motion presented in the current shot are determined using a set of homographic transforms, estimated by recursively applying the RANSAC algorithm on the interest point correspondence. Finally, a decision is taken based on the combined information from both saliency maps. The experimental results validate the proposed framework and demonstrate that our approach is suitable for various types of videos and is robust to noise and low resolution.

关键词： Visualization Humans Computational modeling Streaming media Spatiotemporal phenomena Cameras Transforms

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Postnatal Development of the Retina in Rats Exposed to Hyperoxia: A Fractal Analysis

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International Scholarly Research Notices 2013年第1期2013卷

作者： Anne Claudia Ştefănuţ Ştefan Ţălu Viorel Miclăuş Adriana Mureşan Remus Moldovan Bianca Szabo Clinic Emergency Hospital Cluj-Napoca 3-5 Clinicilor Street 400006 Cluj-Napoca Romania Technical University of Cluj-Napoca Faculty of Mechanical Engineering Department of AET Discipline of Descriptive Geometry and Engineering Graphics 103-105 B-dul Muncii Street 400641 Cluj-Napoca Romaniautcluj.ro University of Agricultural Sciences and Veterinary Medicine Faculty of Veterinary Medicine Department of Cell Biology Histology and Embriology 3-5 Mănăştur Street 400372 Cluj-Napoca Romania “Iuliu Haţieganu” University of Medicine and Pharmacy Cluj-Napoca Faculty of Medicine Department of Physiology 1 Clinicilor Street 400006 Cluj-Napoca Romania “Iuliu Haţieganu” University of Medicine and Pharmacy Cluj-Napoca Faculty of Medicine Department of Anatomy Embryology Ophthalmology 3-5 Clinicilor Street 400006 Cluj-Napoca Romania

Purpose . The aim of this study was to investigate and quantify changes in the newborn rats retinal layers during the hyperoxia (80% O 2 ) exposure using fractal analysis. Materials and Methods . This study was conducted on two groups of 20 newborn rats: a control (normal) group (10 rats) and an experimental group (10 rats). The control group was composed of 10 newborn rats, which were placed at 12 hours after birth, in a pediatric incubator, together with their mother, in conditions of normoxia for 21 days. The experimental group consisted of 10 newborn rats, which were placed at 12 hours after birth, in a pediatric incubator with their mother, in conditions of normoxia for 7 days, then 7 days of hyperoxia (80% O 2 ) for 22.5 hours/day, and then 7 days in conditions of normoxia. Slaughtering of the rats was performed on day 21 and the eye globes were harvested in order to perform histopathological examinations. The fractal analyses of the retinal digital images were performed using the fractal analysis software Image J, and the fractal dimensions were calculated using the standard box-counting method. Results . Microscopic examination revealed a normal development of the retina in the control group. In the experimental group, all the animals exposed to hyperoxia revealed both structural and vascular abnormalities on entire retina. Conclusions . The results showed that the fractal analysis is a valuable tool to quantify histoarchitectural changes in the newborn rats retinal layers during the hyperoxia (80% O 2 ).

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Teaching experience in descriptive geometry and engineering graphics: Future engineers of a mining-geological profile

Teaching experience in descriptive geometry and engineering ...

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Joint International IGIP-SEFI Annual Conference 2010

作者： Tatyana, Vereshchagina Perm State Technical University Department of Design Graphics and Descriptive Geometry Russia

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