Andrea Brambilla

PhD student

Publications

2016

    [Bibtex] 
    @MISC {moller2016winter,
author = "Moller, Torsten and Brambilla, Andrea and Hotz, Ingrid and Gordon, Kindlmann and Schulz, Hans Jorg and Hauser, Helwig and Brodtkorb, Andre",
title = "Geilo Winter School in eScience on Scientific Visualization",
year = "2016",
thumbnails = "images/winter.png",
note = "https://www.cs.ubc.ca/~tmm/talks.html",
journal = "Geilo Winter School of eSience"
}
    [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

    [DOI] [Bibtex] 
    @ARTICLE {Brambilla15Expressive,
author = "Andrea Brambilla and Helwig Hauser",
title = "Expressive Seeding of Multiple Stream Surfaces for Interactive Flow Exploration",
journal = "Computers \& Graphics",
year = "2015",
volume = "47",
pages = "123--134",
abstract = "Integral surfaces, such as stream and path surfaces, are highly effective in the context of the exploration and the analysis of the long-term behavior of three-dimensional flows. However, specifying the seeding curves that lead to an expressive set of integral surfaces is a challenging and cumbersome task. In this paper, we propose an algorithm for automatically seeding multiple stream surfaces around a user-specified location of interest. The process is guided by a streamline similarity measure. Within the resulting integral surfaces, adjacent streamlines are as similar as possible to each other. In addition, we aim at conveying different aspects of the flow behavior with each surface. This is achieved by maximizing the dissimilarity between streamlines from different stream surfaces. The capabilities of our technique are demonstrated on a number of application cases. We provide a qualitative comparison with two state-of-the-art approaches. We report from our detailed exchange with a domain expert concerning the expressiveness and usefulness of our approach. A thorough analysis of the few parameters involved is provided. ",
images = "images/Brambilla15Expressive01.png, images/Brambilla15Expressive02.png",
thumbnails = "images/Brambilla15Expressive01_thumb.png, images/Brambilla15Expressive02_thumb.png",
publisher = "Elsevier",
doi = "http://dx.doi.org/10.1016/j.cag.2015.01.002",
url = "http://www.sciencedirect.com/science/article/pii/S0097849315000035",
keywords = "Flow visualization; Stream surface selection; Visibility management"
}

2014

    [Bibtex] 
    @PHDTHESIS {brambilla14thesis,
author = "Andrea Brambilla",
title = "Visibility-oriented Visualization Design for Flow Illustration",
school = "Department of Informatics, University of Bergen, Norway",
year = "2014",
month = "December",
abstract = "Flow phenomena are ubiquitous in our world and they affect many aspects of our daily life. For this reason, they are the subject of extensive studies in several research fields. In medicine, the blood flow through our vessels can reveal important information about cardiovascular diseases. The air flow around a vehicle and the motion of fluids in a combustion engine are examples of relevant flow phenomena in engineering disciplines. Meteorologists, climatologists and oceanographers are instead concerned with winds and water currents. Thanks to the recent advancements in computational fluid dynamics and to the increasing power of modern hardware, accurate simulations of flow phenomena are feasible nowadays. The evolution of multiple flow attributes, such as velocity, temperature and pressure, can be simulated over large spatial and temporal domains (4D). The amount of data generated by this process is massive, therefore visualization techniques are often adopted in order to ease the analysis phase. The overall goal is to convey information about the phenomena of interest through a suitable representation of the data at hand. Due to the multivariate and multidimensional nature of the data, visibility issues (such as cluttering and occlusion), represent a significant challenge. Flow visualization can greatly benefit from studying and addressing visibility issues already in the design phase. In this thesis we investigate and demonstrate the effectiveness of taking visibility management into account early in the design process. We apply this principle to three characteristic flow visualization scenarios: (1) The simultaneous visualization of multiple flow attributes. (2) The visual inspection of single and multiple integral surfaces. (3) The selection of seeding curves for constructing families of integral surfaces. Our techniques result in clutter- and occlusion-free visualizations, which effectively illustrate the key aspects of the flow behavior. For demonstration purposes, we have applied our approaches to a number of application cases. Additionally, we have discussed our visualization designs with domain experts. They showed a genuine interest in our work and provided insightful suggestions for future research directions.",
images = "images/brambilla14thesis_0.png, images/brambilla14thesis_1.png,",
thumbnails = "images/brambilla14thesis_0_thumb.png, images/brambilla14thesis_1_thumb.png,",
isbn = "978-82-308-2753-6",
url = "http://hdl.handle.net/1956/8961"
}
    [Bibtex] 
    @MISC {Brambilla14Video,
author = "Andrea Brambilla",
title = "Video Visualization: An Overview",
howpublished = "Trial lecture, University of Bergen",
month = "November",
year = "2014",
abstract = "Videos are one of the most widespread media for collecting, communicating and archiving information. Nowadays, acquiring videos is a relatively straightforward process, and this explains their success in the context of entertainment, surveillance, sport events, and so on. On the other hand, watching and extracting information from a video stream is a lengthy process. Automatic techniques are only partially sucessful because of the intrinsic complexity of this kind of data. Video visualization is a growing research field which aims at easying the study of video data. It relies on both automatic techniques and user interaction, exploiting the best of both worlds. In this talk, I will introduce this field, focusing on its evolution from computer vision. I will discuss the main challenges and present an overview of the state-of-the-art. The talk will conclude with a discussion of the open problems and the expected future developments.",
images = "images/Brambilla14Video.png",
thumbnails = "images/Brambilla14Video.png",
location = "Bergen, Norway",
pres = "pdfs/Brambilla14Video.pptx"
}
    [Bibtex] 
    @MISC {Brambilla14Visualizing,
author = "Andrea Brambilla",
title = "Visualizing the Long-term Behavior of 3D Fluid Flows",
howpublished = "Presentation at the Konversatorium, Institute for Computer Graphics and Algorithm, TU Wien",
month = "April",
year = "2014",
abstract = "The study of the long-term behavior of 3D fluid flows can provide useful insights into transport phenomena, which are of central importance in many fields, such as medicine and engineering. Such a study is normally based on the integration of the flow field. The resulting integral structures are indeed highly expressive, but their direct visualization often suffers from cluttering and occlusion issues. In this talk I will present my recent (and future) work addressing this problem. Three projects will be covered: (1) A seeding strategy for families of integral surfaces, which captures the predominant aspects of the long-term flow behavior. (2) A technique for easing the investigation and comparison of surface families, based on a 2D reformation process. (3) The work I am carrying out here at the TU, aimed at quantifying transport phenomena and depicting them using Sankey diagrams.",
images = "images/Brambilla14Visualizing.png",
thumbnails = "images/Brambilla14Visualizing.png",
location = "Wien, Austria",
url = "http://www.cg.tuwien.ac.at/courses/konversatorium/2014-04-25",
pres = "pdfs/Brambilla14Visualizing.pdf"
}
    [Bibtex] 
    @MISC {Brambilla14Visibility,
author = "Andrea Brambilla",
title = "Visibility Management in Integration-based Flow Visualization",
howpublished = "Talk at the Department of Informatics, Systems and Communication, University of Milano - Bicocca",
month = "June",
year = "2014",
abstract = "The analysis of flow phenomena holds an important role in several fields, such as engineering and medicine. Flow visualization techniques aim at easing the investigation process by depicting the flow data through graphical entities. Specifically, integration-based methods employ lines and surfaces in order to visualize the long-term behavior of fluid particles. In this talk, I will give a brief introduction to integration-based flow visualization, present its advantages and discuss its main limitations, i.e., cluttering and occlusion. I will then present my recent work addressing these limitations. Two projects will be described: (1) A selection strategy for integral surfaces, which aims at detecting a small number of highly informative integral surfaces. (2) A technique for easing the investigation and comparison of surface families, based on a 2D reformation process.",
images = "images/Brambilla14Visualizing.png",
thumbnails = "images/Brambilla14Visualizing.png",
location = "Milan, Italy",
pres = "pdfs/Brambilla14Visibility.pdf"
}

2013

    [PDF] [DOI] [Bibtex] 
    @INPROCEEDINGS {Brambilla13Integrated,
author = "Andrea Brambilla and {\O }yvind Andreassen and Helwig Hauser",
title = "Integrated Multi-aspect visualization of 3D Fluid Flows",
booktitle = "Proc. of VMV 2013: Vision, Modeling \& Visualization",
year = "2013",
pages = "1--9",
month = "Sept.",
abstract = "The motion of a fluid is affected by several intertwined flow aspects. Analyzing one aspect at a time can only yield partial information about the flow behavior. More details can be revealed by studying their interactions. Our approach enables the investigation of these interactions by simultaneously visualizing meaningful flow aspects, such as swirling motion and shear strain. We adopt the notions of relevance and coherency. Relevance identifies locations where a certain flow aspect is deemed particularly important. The related piece of information is visualized by a specific visual entity, placed at the corresponding location. Coherency instead represents the homogeneity of a flow property in a local neighborhood. It is exploited in order to avoid visual redundancy and to reduce occlusion and cluttering. We have applied our approach to three CFD datasets, obtaining meaningful insights.",
pdf = "pdfs/Brambilla13Integrated.pdf",
images = "images/Brambilla13Integrated_00.png, images/Brambilla13Integrated_01.png",
thumbnails = "images/Brambilla13Integrated_thumb00.png, images/Brambilla13Integrated_thumb01.png",
proceedings = "Proc. of VMV 2013: Vision, Modeling \& Visualization",
url = "http://diglib.eg.org/EG/DL/PE/VMV/VMV13/001-009.pdf",
doi = "10.2312/PE.VMV.VMV13.001-009",
location = "Lugano, Switzerland",
pres = "pdfs/Brambilla13Integrated.pptx",
extra = "extra/Brambilla13Integrated_extra.pdf"
}
    [PDF] [Bibtex] 
    @ARTICLE {Parulek13Fast,
author = "Julius Parulek and Andrea Brambilla",
title = "Fast Blending Scheme for Molecular Surface Representation",
journal = "Visualization and Computer Graphics, IEEE Transactions on",
year = "2013",
pages = "2653--2662",
month = "Dec.",
abstract = "Representation of molecular surfaces is a well established way to study the interaction of molecules. The state-of-theart molecular representation is the SES model, which provides a detailed surface visualization. Nevertheless, it is computationally expensive, so the less accurate Gaussian model is traditionally preferred. We introduce a novel surface representation that resembles the SES and approaches the rendering performance of the Gaussian model. Our technique is based on the iterative blending of implicit functions and avoids any pre-computation. Additionally, we propose a GPU-based ray-casting algorithm that efficiently visualize our molecular representation. A qualitative and quantitative comparison of our model with respect to the Gaussian and SES models is presented. As showcased in the paper, our technique is a valid and appealing alternative to the Gaussian representation. This is especially relevant in all the applications where the cost of the SES is prohibitive.",
pdf = "pdfs/Parulek13Fast.pdf",
images = "images/Parulek13Fast01.png, images/Parulek13Fast02.png",
thumbnails = "images/Parulek13Fast01_thumb.png, images/Parulek13Fast02_thumb.png",
event = "Vis2013",
project = "physioillustration",
extra = "extra/Parulek13Fast_code.pdf"
}

2012

    [PDF] [DOI] [VID] [YT] [Bibtex] 
    @ARTICLE {Birkeland-2012-IMC,
author = "{\AA}smund Birkeland and Stefan Bruckner and Andrea Brambilla and Ivan Viola",
title = "Illustrative Membrane Clipping",
journal = "Computer Graphics Forum",
year = "2012",
volume = "31",
number = "3",
pages = "905--914",
month = "jun",
abstract = "Clipping is a fast, common technique for resolving occlusions. It  only requires simple interaction, is easily understandable, and thus  has been very popular for volume exploration. However, a drawback  of clipping is that the technique indiscriminately cuts through features.  Illustrators, for example, consider the structures in the vicinity  of the cut when visualizing complex spatial data and make sure that  smaller structures near the clipping plane are kept in the image  and not cut into fragments. In this paper we present a new technique,  which combines the simple clipping interaction with automated selective  feature preservation using an elastic membrane. In order to prevent  cutting objects near the clipping plane, the deformable membrane  uses underlying data properties to adjust itself to salient structures.  To achieve this behaviour, we translate data attributes into a potential  field which acts on the membrane, thus moving the problem of deformation  into the soft-body dynamics domain. This allows us to exploit existing  GPU-based physics libraries which achieve interactive frame rates.  For manual adjustment, the user can insert additional potential fields,  as well as pinning the membrane to interesting areas. We demonstrate  that our method can act as a flexible and non-invasive replacement  of traditional clipping planes.",
pdf = "pdfs/Birkeland-2012-IMC.pdf",
vid = "vids/Birkeland12Illustrative.avi",
images = "images/Birkeland12Illustrative01.png, images/Birkeland12Illustrative02.png, images/Birkeland12Illustrative03.png",
thumbnails = "images/Birkeland-2012-IMC.png",
youtube = "https://www.youtube.com/watch?v=I89_--zul6c",
note = "presented at EuroVis 2012",
doi = "10.1111/j.1467-8659.2012.03083.x",
event = "EuroVis 2012",
keywords = "clipping, volume rendering, illustrative visualization",
location = "Vienna, Austria",
project = "illustrasound,medviz,illvis",
url = "http://www.cg.tuwien.ac.at/research/publications/2012/Birkeland-2012-IMC/"
}
    [PDF] [DOI] [Bibtex] 
    @INPROCEEDINGS {Brambilla12Illustrative,
author = "Andrea Brambilla and Robert Carnecky and Ronald Peikert and Ivan Viola and Helwig Hauser",
title = "Illustrative Flow Visualization: State of the Art, Trends and Challenges",
booktitle = "EuroGraphics 2012 State of the Art Reports (STARs)",
year = "2012",
pages = "75--94",
abstract = "Flow visualization is a well established branch of scientific visualization and it currently represents an invaluable resource to many fields, like automotive design, meteorology and medical imaging. Thanks to the capabilities of modern hardware, flow datasets are increasing in size and complexity, and traditional flow visualization techniques need to be updated and improved in order to deal with the upcoming challenges. A fairly recent trend to enhance the expressiveness of scientific visualization is to produce depictions of physical phenomena taking inspiration from traditional handcrafted illustrations: this approach is known as illustrative visualization, and it is getting a foothold in flow visualization as well. In this state of the art report we give an overview of the existing illustrative techniques for flow visualization, we highlight which problems have been solved and which issues still need further investigation, and, finally, we provide remarks and insights on the current trends in illustrative flow visualization.",
pdf = "pdfs/Brambilla12Illustrative.pdf",
images = "images/Brambilla12Illustrative.png",
thumbnails = "images/Brambilla12Illustrative_thumb.png",
url = "http://diglib.eg.org/EG/DL/conf/EG2012/stars/075-094.pdf",
doi = "10.2312/conf/EG2012/stars/075-094",
location = "Cagliari, Italy",
pres = "pdfs/Brambilla12Illustrative.pptx",
project = "semseg"
}
    [PDF] [Bibtex] 
    @MISC {Brambilla12Geilo,
author = "Andrea Brambilla and Armin Pobitzer and Helwig Hauser",
title = "Flow Visualization and the SemSeg project",
howpublished = "Poster presented at the Sintef winter school 2012",
month = "January",
year = "2012",
pdf = "pdfs/Brambilla12Geilo.pdf",
images = "images/Brambilla12Geilo01.png",
thumbnails = "images/Brambilla12Geilo01_thumb.png",
location = "Geilo, Norway",
url = "http://www.sintef.no/Projectweb/eVITA/Winter-Schools/2012/"
}
    [PDF] [Bibtex] 
    @ARTICLE {Brambilla12AHierarchical,
author = "Andrea Brambilla and Ivan Viola and Helwig Hauser",
title = "A Hierarchical Splitting Scheme to Reveal Insight into Highly Self-Occluded Integral Surfaces",
journal = "Journal of WSCG",
year = "2012",
volume = "20",
number = "1",
pages = "57--64",
month = "July",
abstract = "In flow visualization, integral surfaces are of particular interest for their ability to describe trajectories of massless particles. In areas of swirling motion, integral surfaces can become very complex and difficult to understand. Taking inspiration from traditional illustration techniques, such as cut-aways and exploded views, we propose a surface analysis tool based on surface splitting and focus+context visualization. Our surface splitting scheme is hierarchical and at every level of the hierarchy the best cut is chosen according to a surface complexity metric. In order to make the interpretation of the resulting pieces straightforward, cuts are always made along isocurves of specific flow attributes. Moreover, a degree of interest can be specified, so that the splitting procedure attempts to unveil the occluded interesting areas. Through practical examples, we show that our approach is able to overcome the lack of understanding originating from structural occlusion.",
pdf = "pdfs/Brambilla12AHierarchical.pdf",
images = "images/Brambilla12AHierarchical01.png, images/Brambilla12AHierarchical02.png, images/Brambilla12AHierarchical03.png",
thumbnails = "images/Brambilla12AHierarchical01_thumb.png, images/Brambilla12AHierarchical02_thumb.png, images/Brambilla12AHierarchical03_thumb.png",
issn = "1213-6972",
publisher = "Union Agency",
url = "http://wscg.zcu.cz/JWSCG/",
event = "WSCG 2012 - 20th International Conference on Computer Graphics, Visualization and Computer Vision",
location = "Pilsen, Czech Republic",
pres = "pdfs/Brambilla12AHierarchical.pptx",
project = "semseg"
}
    [Bibtex] 
    @MISC {Brambilla12SemSegWorkshop,
author = "Andrea Brambilla and Robert Carnecky",
title = "Introduction to Illustrative Flow Visualization",
howpublished = "Presentation at the 3rd SemSeg User Forum Workshop",
month = "February",
year = "2012",
images = "images/Brambilla12Illustrative.png",
thumbnails = "images/Brambilla12Illustrative_thumb.png",
location = "Magdeburg, Germany",
url = "http://vc.cs.ovgu.de/index.php?article_id=232",
pres = "pdfs/Brambilla12SemSegWorkshop.pdf",
project = "semseg"
}