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30th SIBGRAPI Conference on graphics, Patterns and images Tutorials (SIBGRAPI-T)

作者： Rodrigues, Livia Rittner, Leticia Lotufo, Roberto Souza, Roberto Frayne, Richard Univ Estadual Campinas Fac Elect & Comp Engn Med Image Comp Lab Campinas SP Brazil Univ Calgary Hotchkiss Brain Inst Dept Radiol & Clin Neurosci Calgary AB Canada

ISBN: (纸本)9781538622193

Atherosclerosis is a disease responsible for millions of deaths each year, primarily due to heart attack and stroke. Magnetic resonance (MR) imaging is a non-invasive method that can be used to analyze the carotid artery and detect signs of atherosclerosis. Most MR methods acquire high contrast, static images. these methods, however, are sensitive to artifacts from cardiac motion, produce time-averaged images, and do not allow for carotid distensibility analysis. Carotid distensibility is an important, systematic measure of vascular health. Cine fast spin echo (FSE) is a new MR imaging that can obtain dynamic MR data (i.e., cardiac phase-resolved datasets). Dynamic imaging, however, comes at the cost of lower spatial resolution and signal-to-noise ratio, making these data potentially more difficult to segment. this paper introduces a semi-automated segmentation method that segments the common carotid artery (CCA) lumen across the cardiac cycle from dynamic MR images. To the best of our knowledge, this work is the first proposed technique for segmenting cardiac cycle-resolved cine FSE images. It combines a priori knowledge about the size and shape of the CCA, with the max-tree data structure, the tie-zone watershed transform (using identified internal and external markers) and supervised classification, to segment the carotid artery wall-lumen boundary. the user has to select only a seed point (centred in the carotid artery lumen). Technique performance was assessed using forty-five cine FSE data sets, each consisting of images reconstructed at sixteen temporal bins across the cardiac cycle. the automatic segmentation results were compared against the consensus of three different manual segmentation results. Our technique achieved an average Dice coefficient, sensitivity and false positive rate of 0.928 +/- 0.031 (mean +/- standard deviation), 0.915 +/- 0.037 and 0.056 +/- 0.049, respectively. Our method achieved higher agreement versus the consensus of the three man

关键词： max-tree watershed transform carotid artery imaging carotid artery segmentation carotid artery distensibility cine FSE

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Single-image shape from defocus

Single-image shape from defocus

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SIBGRAPI 2005: 18th brazilian symposium on computer graphics and image processing - Conference Proceedings

作者： Torreão, José R. A. Fernandes, João L. Instituto de Computação Universidade Federal Fluminense 24210-240 Niterói RJ Brazil

ISBN: (纸本)0769523897

the limited depth of field causes scene points at various distances from a camera to be imaged with different amounts of defocus. If images captured under different aperture settings are available, the defocus measure can be estimated and used for 3D scene reconstruction. Usually, defocusing is modeled by gaussian convolution over local image patches, but the estimation of a defocus measure based on that is hampered by the spurious high-frequencies introduced by windowing. Here we show that this can be ameliorated by the use of unnormalized gaussians, which allow defocus estimation from the zero-frequency Fourier component of the image patches, thus avoiding spurious high frequencies. As our main contribution, we also show that the modified shape from defocus approach can be extended to shape estimation from single shading inputs. this is done by simulating an aperture change, via gaussian convolution, in order to generate the second image required for defocus estimation. As proven here, the gaussian-blurred image carries an explicit depth-dependent blur component - which is missing from an ideal shading input -, and thus allows depth estimation as in the multi-image case. © 2005 IEEE.

关键词： image reconstruction

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A mixture of two gender classification experts

A mixture of two gender classification experts

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25th Conference on graphics, Patterns and images, SIBGRAPI 2012

作者： El-Din, Yomna Safaa Moustafa, Mohamed N. Mahdi, Hani Department of Computer and Systems Engineering Ain Shams University Cairo Egypt Department of Computer Science and Engineering American University in Cairo New Cairo Egypt

ISBN: (纸本)9780769548296

this paper presents a novel method for combining the outputs of different gender classification techniques based on facial images. Merging the methods is performed by a committee machine using the Bayesian theorem. We implement and compare several well-known individual classifiers on four different datasets, then we experiment the proposed machine, and show that it significantly improves the accuracy of classification compared to individual classifiers. We also include results that address the effect of scale on the performance of classifiers. © 2012 IEEE.

关键词： Classification (of information)

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Analysis of the statistical significance of 3D texture features in MRI images toward the detection of Tourette's Syndrome 35

Analysis of the statistical significance of 3D texture featu...

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35th SIBGRAPI Conference on graphics, Patterns and images (SIBGRAPI)

作者： de Barros, Murilo Costa Duarte, Kaue T. N. Lee, Wang-Tso Hsu, Chia-Jui de Carvalho, Marco Antonio G. Univ Estadual Campinas Sch Technol UNICAMP Comp Visual Lab R Paschoal Marmo 1888 Limeira Brazil Univ Calgary Vasc Imaging Lab 2500 Univ Dr NW Calgary AB T2N IN4 Canada Natl Taiwan Univ Childrens Hosp Dept Pediat Taipei Taiwan Natl Taiwan Univ Hosp Dept Pediat Hsinchu Branch Taipei Taiwan

ISBN: (数字)9781665453851

ISBN: (纸本)9781665453851

Tourette Syndrome (TS) is a genetically induced disorder that is believed to be caused by morphological alterations in brain structure, resulting in involuntary movements known as tics. the current clinical standard for diagnosing TS is by clinical assessments performed by physicians. Mild stages of TS, however, commonly go underdiagnosed as tics are infrequent or often suppressed. Brain imaging has been suggested to be a reliable tool to detect brain alterations and possible biomarkers that correspond to neurological disorders. In Magnetic Resonance Imaging (MRI), anatomical brain changes can be identified in the scan by variation in texture patterns of certain regions. the main goal of this work is to identify the statistical significance of texture features in specific brain regions to distinguish TS from control subjects. the proposed approach consists of four main steps: (i) image acquisition, where the data is also organized using demographic information;(ii) brain segmentation, where the structural MRI is parcellated into anatomical regions;(iii) registration, where functional MRI is aligned to structural MRI;(iv) obtaining texture features and statistical analysis, where texture features are extracted from the anatomical brain regions. We adopted 68 subjects aged between 6 to 14 years, divided equally into TS and Normal Control groups. We evaluated the texture features in a statistical manner, where our main findings are: (i) After False Discovery Rate (FDR) correction, only one texture feature was significant (p-value < 0.08) in structural MRI;(ii) Following FDR correction, eight texture features in functional MRI for three anatomical regions were considered significant;(iii) the right amygdala presented significance in distinct texture features, matching its importance in the literature. Texture features aligned with the literature can serve as a reliable tool to identify imaging changes, which can lead to future work applied to clinical studies.

关键词： Brain image segmentation Visualization three-dimensional displays Statistical analysis Functional magnetic resonance imaging Feature extraction

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Stochastic texture image retrieval and similarity matching 13

Stochastic texture image retrieval and similarity matching

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13th brazilian symposium on computer graphics and image processing, SIBGRAPI 2000

作者： Jung, C.R. Scharcanski, J. UFRGS - Universidade Federal do Rio Grande do Sul Instituto de Informática Av. Bento Gonçalves 9500 Porto Alegre RS91501-970 Brazil UNISINOS - Universidade do Vale do Rio dos Sinos Departamento de Matemática Av. Unisinos 950 São Leopoldo RS93022-000 Brazil

ISBN: (纸本)0769508782

Stochastic texture images representing various foil materials (like polymer sheets, nonwoven textiles and paper) provide important information about these materials, and are very utilized in industry. Often, it is difficult to objectively measure the similarity among those images, or to discriminate images of different types of materials. this work proposes a new multi-resolution method for texture image discrimination and similarity matching. the wavelet transform is used to represent the images in multiple resolutions, and to describe them in terms of their orientation and graylevel distributions. It is also proposed a multi-resolution similarity measure based on this representation. Finally, some experiments illustrate the performance of our method, and some conclusions are presented. © 2000 IEEE.

关键词： Quality control

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Sketch-finder: Efficient and effective sketch-based retrieval for large image collections

Sketch-finder: Efficient and effective sketch-based retrieva...

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2013 26th Conference on graphics, Patterns and images, SIBGRAPI 2013

作者： Filho, Carlos A.F. Arajujo, Arnaldo De A. Crucianu, Michel Gouet-Brunet, Valerie Federal University of Minas Gerais Computer Science Department Belo Horizonte - MG Brazil Cnam-CEDRIC France IGN Laboratoire MATIS France

ISBN: (纸本)9780769550992

Among various image retrieval approaches, the use of sketches lets one express a precise visual query with simple and widespread means. the challenge consists in finding a content representation that allows you to effectively compare sketches and images, while supporting efficient retrieval in order to make the system scalable. We put forward a sketch-based image retrieval solution where sketches and natural image contours are represented and compared in the wavelet domain. the relevant information regarding query sketches and image content has, thus, a compact representation that can be readily employed by an efficient index for retrieval by similarity. Furthermore, with this solution, the balance between effectiveness and efficiency can be easily modified in order to adapt to the available resources. A comparative evaluation with a state-of-the-art method on the Paris dataset and a subset with 535K images of the image Net dataset shows that our solution can preserve effectiveness while being more than one order of magnitude faster. © 2013 IEEE.

关键词： image retrieval

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Combining human-computer interaction techniques to evaluate content-based image retrieval systems 08

Combining human-computer interaction techniques to evaluate ...

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14th brazilian symposium on Multimedia and the Web - WebMedia 2008

作者： Filardi, Ana Lúcia Traina, Agma Juci MacHado Embrapa Monitoramento Por Satélite Av. Soldado Passarinho 303 13070-115 - Campinas SP Brazil Universidade de São Paulo Av. do Trabalhador Sao-Carlense 40 13560-970 - Sao Carlos SP Brazil

ISBN: (纸本)9781605581705

the human interaction is a valuable tool to evaluate the performance of a Content-based image Retrieval (CBIR) system regarding its efficiency and efficacy, as well as the user satisfaction. the fast growing and the strength achieved in the CBIR research field has brought relevant improvement to the pictorial information retrieval, but it is not supported by techniques or guidelines to help evaluating the usability of such systems. thus, a challenge of CBIR systems is to provide the users intuitive ways to ask queries and to receive their answers increasing the usefulness of such systems. the goal of this paper is to present an approach to evaluate the human-computer interaction of CBIR systems. To do so, we employed a combination of evaluation techniques considering the final users and the human factors that influence their work, taking also into account the large amount of images and data stored in these systems. As a case study, we used a CBIR system for medical images, which was developed aimed at supporting the decision making when the physician is drawing the diagnosis. Our study aimed at improving the diagnoses, as well as the evolution of the patients' treatment, making both more precise and efficient. Copyright © held by author/owner.

关键词： Patient treatment

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Simulation and Evaluation of Deep Learning Autoencoders for image Compression in Multi-UAV Network Systems 20

Simulation and Evaluation of Deep Learning Autoencoders for ...

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20th Latin American Robotics symposium (LARS) / 15th brazilian symposium on Robotics (SBR) / 14th Workshop on Robotics in Education (WRE)

作者： Ramos, Gabryel Silva de Lima, Amaro Azevedo Almeida, Luciana F. Lima, Jose Pinto, Milena Faria CEFET RJ Elect Engn Dept Rio De Janeiro Brazil Inst Politecn Braganca Res Ctr Digitalizat & Intelligent Robot CeDRI Braganca Portugal

ISBN: (纸本)9798350315387

Mobile multi-robot systems are versatile alternatives for improving single-robot capacities in many applications, such as logistics, environmental monitoring, search and rescue, photogrammetry, etc. In this sense, this kind of system must have a reliable communication network between the vehicles, ensuring that information exchanged within the nodes has little losses. this work simulates and evaluates the use of autoencoders for image compression in a multi-UAV simulation with ROS and Gazebo for a generic surveillance application. the autoencoder model was developed with the Keras library, presenting good training and validation results, with training and validation accuracy of 70%, and a Peak Signal Noise Ratio (PSNR) of 40dB. the use of the CPU for the simulated UAVs for processing and sending compressed images through the network is 25% faster. the results showed that this compression methodology is a good choice for improving the system's performance without losing too much information.

关键词： component formatting style styling insert

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A model for distributed medical image processing using CORBA

A model for distributed medical image processing using CORBA

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14th IEEE symposium on computer-Based Medical Systems (CBMS 2001)

作者： Barros, ED Sehn, M von Wangenheim, A Krechel, D Univ Fed Santa Catarina Dept Comp Sci Cyclops Project BR-88040900 Florianopolis SC Brazil

ISBN: (纸本)0769510043

this paper presents the IIADPS (Integrated image Access and Distributed processing Service) model, a software environment that allows radiological medical teams to have access to distributed image processing facilities in conformance to the DICOM 3.0 (Digital image Communications in Medicine) standard. the model, allows to remotely, execute distributed image processing for diagnosis tasks on any low-cost equipment located on a local network Or high-speed wide-area network. the model was developed due to the enormous computational processing requirements normally posted to these tasks Our approach allows low-cost equipment located in a network to be used, independently of the operational system, to execute the distributed image processing, leading to a significant reduction in the processing time. this enables also hospitals which do not have radiological stations of high processing capability to use low-cost PC networks for this purpose.

关键词： image analysis

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Initial experience with soft-copy display of computed radiography images on three picture archive and communication systems

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JOURNAL OF DIGITAL IMAGING 1997年第3期10卷 47-50页

作者： Hangiandreou, NJ Cesar, LJ Bruesewitz, MR Hartman, TE King, BF Rose, JF Swee, RG Wenger, DE James, EM Gray, JE Department of Diagnostic Radiology Mayo Clinic and Foundation Rochester MN USA.

We recently installed picture archive and communication systems (PACS) from three different vendors on our campus for evaluation. A major part of this evaluation involved assessing the capabilities of these systems for displaying computed radiography (CR) images for primary interpretation. the three PACS provided different functionality for CR image display in terms of availability of the proprietary Fuji CR image processing algorithms, availability of user-specified contrast look-up tables, and application of the processing at the time of CR image capture or image display. We found that the Fuji processing algorithms were important for printing film, but were not necessary for acceptable soft-copy display. Non-linear contrast processing produced superior results compared to simple linear processing (via standard window width and level controls), Display processing was best applied immediately prior to the display operation, as opposed to at the image capture time. this allows the display to be adjusted to demonstrate the full 10-bit range of the CR image, and also allows raw CR data (i.e. not optimized for any particular display device) to be stored in the long-term archive. Copyright (C) 1997 by W.B. Saunders Company.

关键词： picture archive and communication systems (PACS) computed radiography soft-copy image display filmless radiology

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