Paolo Angelelli

project post-doc

(ultrasound visualization, ...)

Publications

2016

    [PDF] [Bibtex] 
    @ARTICLE {brambilla2016comparative,
author = "Brambilla, Andrea and Angelelli, Paolo and Andreassen, yvind and Hauser, Helwig",
title = "Comparative visualization of multiple time surfaces by planar surface reformation",
journal = "Pacific Visualization Symposium (PacificVis), 2016 IEEE",
year = "2016",
pages = "88--95",
abstract = "Comparing time surfaces at different integration time points, or
from different seeding areas, can provide valuable insight into
transport phenomena of fluid flows. Such a comparative study is
challenging due to the often convoluted shapes of these surfaces.
We propose a new approach for comparative flow visualization
based on time surfaces, which exploits the idea of embedding the
surfaces in a carefully designed, reformed 2D visualization space.
Such an embedding enables new opportunities for comparative flow
visualization. We present three different strategies for comparative
flow visualization that take advantage of the reformation. By reforming the time surfaces, we not only mitigate occlusion issues,
but we can devote also the third dimension of the visualization
space to the comparative aspects of the visualization. Our approach
is effective in a variety of flow study cases. The direct comparison
of individual time surfaces reveals small scale differences and fine
details about the fluid’s motion. The concurrent study of multiple
surface families enables the identification and the comparison of
the most prominent motion patterns. This work was developed in
close collaboration with an expert in fluid dynamics, who assessed
the potential usefulness of this approach in his field.",
pdf = "pdfs/bambarilla.pdf",
thumbnails = "images/bambarilla_1.png"
}

2015

    [PDF] [Bibtex] 
    @ARTICLE {Angelelli-2015-PQA,
author = "Paolo Angelelli and Stefan Bruckner",
title = "Performance and Quality Analysis of Convolution-Based Volume Illumination",
journal = "Journal of WSCG",
year = "2015",
volume = "23",
number = "2",
pages = "131--138",
month = "jun",
abstract = "Convolution-based techniques for volume rendering are among the fastest  in the on-the-fly volumetric illumination category. Such methods,  however, are still considerably slower than conventional local illumination  techniques. In this paper we describe how to adapt two commonly used  strategies for reducing aliasing artifacts, namely pre-integration  and supersampling, to such techniques. These strategies can help  reduce the sampling rate of the lighting information (thus the number  of convolutions), bringing considerable performance benefits. We  present a comparative analysis of their effectiveness in offering  performance improvements. We also analyze the (negligible) differences  they introduce when comparing their output to the reference method.  These strategies can be highly beneficial in setups where direct  volume rendering of continuously streaming data is desired and continuous  recomputation of full lighting information is too expensive, or where  memory constraints make it preferable not to keep additional precomputed  volumetric data in memory. In such situations these strategies make  single pass, convolution-based volumetric illumination models viable  for a broader range of applications, and this paper provides practical  guidelines for using and tuning such strategies to specific use cases.",
pdf = "pdfs/Angelelli-2015-PQA.pdf",
images = "images/Angelelli-2015-PQA.jpg",
thumbnails = "images/Angelelli-2015-PQA.png",
keywords = "volume rendering, global illumination, scientific visualization, medical visualization"
}

2014

    [PDF] [DOI] [Bibtex] 
    @INPROCEEDINGS {Angelelli-2014-LUP,
author = "Paolo Angelelli and Sten Roar Snare and Siri Ann Nyrnes and Stefan Bruckner and Helwig Hauser and Lasse L{\o}vstakken",
title = "Live Ultrasound-based Particle Visualization of Blood Flow in the Heart",
booktitle = "Proceedings of SCCG 2014",
year = "2014",
pages = "42--49",
month = "may",
abstract = "We introduce an integrated method for the acquisition, processing  and visualization of live, in-vivo blood flow in the heart. The method  is based on ultrasound imaging, using a plane wave acquisition acquisition  protocol, which produces high frame rate ensemble data that are efficiently  processed to extract directional flow information not previously  available based on conventional Doppler imaging. These data are then  visualized using a tailored pathlet-based visualization approach,  to convey the slice-contained dynamic movement of the blood in the  heart. This is especially important when imaging patients with possible  congenital heart diseases, who typically exhibit complex flow patterns  that are challenging to interpret. With this approach, it now is  possible for the first time to achieve a real-time integration-based  visualization of 2D blood flow aspects based on ultrasonic imaging.  We demonstrate our solution in the context of selected cases of congenital  heart diseases in neonates, showing how our technique allows for  a more accurate and intuitive visualization of shunt flow and vortices.",
pdf = "pdfs/Angelelli-2014-LUP.pdf",
images = "images/Angelelli-2014-LUP.jpg",
thumbnails = "images/Angelelli-2014-LUP.png",
doi = "10.1145/2643188.2643200",
keywords = "ultrasound medical visualization, real-time visualization, blood flow visualization",
url = "http://dx.doi.org/10.1145/2643188.2643200"
}
    [DOI] [VID] [Bibtex] 
    @ARTICLE {Angelelli14Interactive,
author = "Paolo Angelelli and Steffen Oeltze and Cagatay Turkay and Judit Haasz and Erlend Hodneland and Arvid Lundervold and Astri Johansen Lundervold and Bernhard Preim and Helwig Hauser",
title = "Interactive Visual Analysis of Heterogeneous Cohort Study Data",
journal = "Computer Graphics and Applications, IEEE",
year = "2014",
volume = "PP",
number = "99",
pages = "1-1",
abstract = "Cohort studies are used in medicine to enable the study of medical hypotheses in large samples. Often, a large amount of heterogeneous data is acquired from many subjects. The analysis is usually hypothesis-driven, i.e., a specific subset of such data is studied to confirm or reject specific hypotheses. In this paper, we demonstrate how we enable the interactive visual exploration and analysis of such data, helping with the generation of new hypotheses and contributing to the process of validating them. We propose a data-cube based model which allows to handle partially overlapping data subsets during the interactive visualization. This model enables the seamless integration of the heterogeneous data, as well as the linking of spatial and non-spatial views on these data. We implemented this model in an application prototype, and used it to analyze data acquired in the context of a cohort study on cognitive aging. In this paper we present a case-study analysis of selected aspects of brain connectivity by using a prototype implementation of the presented model, to demonstrate its potential and flexibility.",
vid = "vids/angelelli14CohortExplorer.wmv",
images = "images/angelelli14Cohort.png",
thumbnails = "images/angelelli14Cohort.png",
doi = "10.1109/MCG.2014.40",
url = "http://dx.doi.org/10.1109/MCG.2014.40"
}

2013

    [PDF] [Bibtex] 
    @MISC {Smestad13Advanced,
author = "Geir Smestad and Paolo Angelelli and Helwig Hauser",
title = "Advanced data fusion in 4-D color doppler volume visualization",
howpublished = "Poster presented at the MedIm conference 2013",
month = "October",
year = "2013",
pdf = "pdfs/Smestad13Advanced.pdf",
images = "images/Smestad13Advanced.jpg",
thumbnails = "images/Smestad13Advanced_thumb.jpg",
location = "Troms{\O }",
project = "bia"
}

2012

    [PDF] [Bibtex] 
    @PHDTHESIS {angelelli12thesis,
author = "Paolo Angelelli",
title = "Visual Exploration of Human Physiology: Visualizing Perfusion, Blood Flow and Aging",
school = "Department of Informatics, University of Bergen, Norway",
year = "2012",
month = "Apr",
abstract = "With the technological advancements in medical imaging, it is nowadayspossible to capture in-vivo information related to different human physiologicalsystems. Such data extends the more traditional anatomical scans,but add size, complexity and heterogeneity. In addition, while anatomydata is defined in three-dimensional space, and 3D graphics techniques canbe used to represent it on the screen, physiology information is often moreabstract, and require tailored solutions to be represented in combinationwith their anatomical context.This thesis presents solutions for visualizing selected aspects in threedomains of physiology: blood flow, perfusion and aging. With respect toblood flow, it includes a technique to enhance the side-by-side visualizationof the tubular flow in vessels. This result is achieved with a methodthat generates straightened visualizations of the flow in its context, whichcan be easily aligned and then related to each other. With respect to perfusion,this thesis includes an interactive visual analysis solution that easeand improve the exploration, segmentation and analysis of perfusion dataacquired using contrast-enhanced ultrasound. This result is achieved byusing a statistical framework to extract enhancement information, and aninteractive, correlation-based approach to classify the tissue based on similarity.Finally, with respect to aging, two solutions to help exploring largedata collections of repeated examinations are presented. In one, interactivevisual analysis methods are employed to explore and analyze cohort studydata, while the other focuses on the guided exploration of repeated ultrasoundexaminations. Demonstration case studies are include to exemplifythe utility of the presented work.",
pdf = "pdfs/angelelli12thesis.pdf",
images = "images/angelelli12thesis.png",
thumbnails = "images/angelelli12thesis_thumb.png",
isbn = "978-82-308-2073-5"
}

2011

    [PDF] [VID] [Bibtex] 
    @ARTICLE {angelelli11straightening,
author = "Paolo Angelelli and Helwig Hauser",
title = "Straightening Tubular Flow for Side-by-Side Visualization",
journal = "IEEE Transactions on Visualization and Computer Graphics",
year = "2011",
volume = "17",
number = "12",
pages = "2063--2070",
abstract = "Flows through tubular structures are common in many fields, including blood flow in medicine and tubular fluid flows in engineering.The analysis of such flows is often done with a strong reference to the main flow direction along the tubular boundary. In this paper we present an approach for straightening the visualization of tubular flow. By aligning the main reference direction of the flow, i.e., the center lineof the bounding tubular structure, with one axis of the screen, we are able to natively juxtapose (1.) different visualizations of the same flow,either utilizing different flow visualization techniques, or by varying parameters of a chosen approach such as the choice of seeding locationsfor integration-based flow visualization, (2.) the different time steps of a time-dependent flow, (3.) different projections around the center line, and (4.) quantitative flow visualizations in immediate spatial relation to the more qualitative classical flow visualization. We describe how to utilize this approach for an informative interactive visual analysis. We demonstrate the potential of our approach by visualizing two datasets from two different fields: an arterial blood flow measurement and a tubular gas flow simulation from the automotive industry.",
pdf = "pdfs/angelelli11straightening.pdf",
vid = "vids/angelelli11TubularFlowStraightening.wmv",
images = "images/angelelli11straightening1.jpg, images/angelelli11straightening2.jpg",
thumbnails = "images/angelelli11straightening1_thumb.jpg, images/angelelli11straightening2_thumb.jpg",
event = "IEEE Visualization Conference 2011",
location = "Providence, RI, USA",
url = "http://dx.doi.org/10.1109/TVCG.2011.235"
}
    [PDF] [VID] [Bibtex] 
    @ARTICLE {angelelli11ultrasoundStatistics,
author = "Paolo Angelelli and Kim Nylund and Odd Helge Gilja and Helwig Hauser",
title = "Interactive Visual Analysis of Contrast-enhanced Ultrasound Databased on Small Neighborhood Statistics",
journal = "Computers \& Graphics - Special Issue on Visual Computing in Biology and Medicine",
year = "2011",
volume = "35",
number = "2",
pages = "218--226",
abstract = "Contrast-enhanced ultrasound (CEUS) has recently become an important technology for lesion detection and characterization in cancer diagnosis. CEUS is used to investigate the perfusion kinetics in tissue over time, which relates to tissue vascularization. In this paper we present a pipeline that enables interactive visual exploration and semi-automatic segmentation and classification of CEUS data.For the visual analysis of this challenging data, with characteristic noise patterns and residual movements, we propose a robust method to derive expressive enhancement measures from small spatio-temporal neighborhoods. We use this information in a stagedvisual analysis pipeline that leads from a more local investigation to global results such as the delineation of anatomic regions according to their perfusion properties. To make the visual exploration interactive, we have developed an accelerated frameworkbased on the OpenCL library, that exploits modern many-cores hardware. Using our application, we were able to analyze datasets from CEUS liver examinations, being able to identify several focal liver lesions, segment and analyze them quickly and precisely, and eventually characterize them.",
pdf = "pdfs/angelelli11CEUSIVA.pdf",
vid = "vids/angelelli11CEUSSegmentation.wmv",
images = "images/angelelli11ultrasoundStatistics2.jpg, images/angelelli11ultrasoundStatistics1.jpg",
thumbnails = "images/angelelli11ultrasoundStatistics2_thumb.jpg, images/angelelli11ultrasoundStatistics1_thumb.jpg",
url = "http://dx.doi.org/10.1016/j.cag.2010.12.005",
project = "illustrasound,medviz,illvis"
}
    [PDF] [Bibtex] 
    @INPROCEEDINGS {schaefer11registration,
author = "Sebastian Sch{\"a}fer and Paolo Angelelli and Kim Nylund and Odd Helge Gilja and Klaus T{\"o}nnies",
title = "Registration of ultrasonography sequences based on temporal regions",
booktitle = "Proc. Intl. Symp. Image and Signal Processing and Analysis (ISPA)",
year = "2011",
pages = "749--754",
abstract = "2D Ultrasonography images with parallel contrast enhanced sequences for analysis constitute a rapid and inexpensive imaging technique with high temporal resolution to assess perfusion of tissue. However, motion from various influences corrupts the inter-pixel correspondences between different time frames and therefore hampers computer-assisted analysis of perfusion parameters. We present a user-supported method applying a temporal similarity matrix to remove frames with uncorrectable out-of-plane motion. For the remaining regions of frames, motion influence can be compensated for by image registration. Subsequently B-Spline based registration is applied using the temporal regions with automatic determination of a suitable reference frame image. Evaluation with ground truth data of six datasets comparing a medical expert frame analysis to the proposed technique yields 85.1% sensitivity and 81.7% specificity in average. On average 6% of the frames have been erroneously included in temporal regions, although they contain out-of-plane motion.",
pdf = "pdfs/schaefer11Registration.pdf",
images = "images/schaefer11registration.jpg",
thumbnails = "images/schaefer11registration_thumb.jpg",
location = "Dubrovnik, Croatia",
url = "http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=6046702"
}

2010

    [PDF] [VID] [Bibtex] 
    @INPROCEEDINGS {angelelli10guided,
author = "Paolo Angelelli and Ivan Viola and Kim Nylund and Odd Helge Gilja and Helwig Hauser",
title = "Guided Visualization of Ultrasound Image Sequences",
booktitle = "Proceedings of Eurographics Workshop on Visual Computing for Biology and Medicine (VCBM)",
year = "2010",
pages = "125--132",
abstract = "Ultrasonography allows informative and expressive real time examinations of patients. Findings are usually reported as printouts, screen shots and video sequences. However, in certain scenarios, the amount of imaged ultrasound data is considerable or it is challenging to detect the anatomical features of interest. Post-examination access to the information present in the data is, therefore, cumbersome. The examiner must, in fact, review entire videosequences or risk to lose relevant information by reducing the examination to single screen shot and printouts. In this paper we propose a novel post-processing pipeline for guided visual exploration of ultrasound video sequences, to allow easier and richer exploration and analysis of the data. We demonstrate the usefulness of this approach by applying it to a liver examination case, showing easier and quicker ultrasound image selection and data exploration.",
pdf = "pdfs/angelelli2010usvideovis.pdf",
vid = "vids/angelelli10DOISound.mp4",
images = "images/angelelli10guided0.jpg, images/angelelli10guided3.jpg, images/angelelli10guided2.jpg, images/angelelli10guided4.jpg",
thumbnails = "images/angelelli10guided0_thumb.jpg, images/angelelli10guided3_thumb.jpg, images/angelelli10guided2_thumb.jpg, images/angelelli10guided4_thumb.jpg",
location = "Leipzig, Germany",
project = "illustrasound,medviz,illvis"
}