Category Archives: News

CGV Colloquium – Tuesday March 15th

You are cordially invited to attend our next Computer Graphics and Visualization (CGV) Colloquium, which will be held on Tuesday March 15, 2016, 14:00-15:00, in the Vassiliadis zaal (HB10.230).

  • Dr. Amir Vaxman, Utrecht University
      • Title – Directional Field Synthesis, Design, and Processing

    amir_lowRes

    • Abstract – Directional fields on discrete surfaces and in volumes are key components of geometry processing. Many applications make use of such fields, among which are remeshing, surface parametrization (texture mapping), texture synthesis, fluid simulation, and many more. I will present the challenges and the limitations in the design and the analysis of such fields, and focus on novel ways to compute them.

CGV Colloquium – Thursday July 16th

You are cordially invited to attend our next Computer Graphics and Visualization (CGV) Colloquium, which will be held on Thursday July 16, 2015, 15.45-17.20, in the Vassiliadis zaal (HB10.230). The program this month features the following speakers:

  • Panchamy Krishnan
    • Title – Supervised learning for measuring hip joint distance in digital X-ray images
    • Abstract – Osteoarthritis is a degenerative joint disease which is hard to measure objectively as the diagnosis differs from surgeon to surgeon.  Hip X-rays are used to diagnose this disease by measuring several characteristic features of the image, mainly the joint distance between the femoral head and acetabular cup.  Joint distance reduction is a clear sign of OA (it is a symptom of cartilage disappearance). This metric involves segmentation of the femur and acetabulum in x-rays, a challenging task because of contrast variations as well as external factors like anatomical and pose-variation. A multi-scale approach based on Machine Learning is proposed here providing a robust segmentation by detecting landmarks along the edges of the bone. The labelled landmarks are then used to determine the joint distance in several locations along the hip joint. The learning is supervised using manually annotated landmarks. The impact of landmark selection is studied in detail in this paper. The landmark detection is further refined using Active Shape Model (ASM) and gradient profiling.
  • Bas Dado
    • Title Compression of voxelized scenes using colored DAGs
    • Abstract – Voxels are great alternative for triangle-meshes. No texture and bump-mapping techniques are necessary to capture fine details, and rendering by means of raycasting is relatively cheap. However, a big dowside of voxels is the large memory footprint, even when a Sparse Voxel Octree (SVO) is used. Directional Acyclic Graphs can be used to reduce this problem but don’t allow for storing materials. We present a technique, based on the DAG compression, to efficiently store the voxel data. The presented technique is smaller than a standard SVO for all tested scenes in high resolution.
  • Kevin Allain
    • Title – Enhancing document triage process using multi layer visualization tool
    • Abstract The European Patent Office is an international organisation that is charged with granting patents for applications sent to their offices. To do so, the examiners have to verify if the claims of the application are indeed new or not, and thus perform a state of the art review. The tools currently used at the EPO return a list of patents that might match the keywords entered by the examiner, but it provides a very poor visualization of the results and document triage is a very cumbersome process. We work on a visualization of all the results from a search query to increase the document triage process, by showing data of all the results at once, offering several levels of details for the examiner to determine the patents that might not be relevant.

As a reminder, all CGV MSc students (both seminar and thesis project) are expected to attend our monthly colloquium series. All other interested colleagues are more than welcome, so feel free to disseminate this announcement.

CGV Colloquium – Thursday June 18th

You are cordially invited to attend our next Computer Graphics and Visualization (CGV) Colloquium, which will be held on Thursday June 18, 2015, 15.45-17.20, in the Vassiliadis zaal (HB10.230).

The program this month features the following speakers:

  • Hongjie Li
    • Title – Automated Expansion of Statistical Shape Model Library for femur
    • Abstract – Currently Clinical Graphics has a Statistical Shape Model (SSM) trained from 275 3D meshes. The SSM can be used to segment MRI data of femur and hip. They also have 2000 partial femur meshes and want to incorporate the partial femur to the SSM training set, so that more reasonable variance can be introduced. My task it set one criteria to decide whether accept and reject the partial femur. Then incorporate the partial bone to the training set, and evaluate whether the new SSM improve the fit accuracy.
  • Fieke Taal
    • Title – Procedural Generation of Traffic Signs
    • Abstract – Designing realistic 3D content in virtual simulations is a hot topic and a challenge, especially in the context of virtual traffic situations considering several users, objects and traffic rules.  Manually generating these virtual environments is not efficient, so procedural methods are needed to create these complex traffic models. The goal of this project is to come up with a procedural method to generate automatically the right traffic signs in a road network.
  • Bas in het Veld
    • Title – Procedural generation of populations for storytelling
    • Abstract – Procedural world generation is often limited to creating worlds devoid of people and any background. Because of this, creating a vibrant, living world is still a problem that requires a skilled designer. We present a method that generates a socially connected population in any virtual terrain, using a mixed-initiative simulation of settlements that adapt to the world and to a designer’s input. Using this simulation, we develop a number of sample worlds that convey the expressive potential of the approach.

As a reminder, all CGV MSc students (both seminar and thesis project) are expected to attend our monthly colloquium series. The next Colloquium is planned on Thursday the 16th of July. All other interested colleagues are more than welcome, so feel free to disseminate this announcement.

CGV Colloquium – Thursday May 21st

You are cordially invited to attend our next Computer Graphics and Visualization (CGV) Colloquium, which will be held on Thursday May 21, 2015, 15.45-17.20, in the Vassiliadis zaal (HB10.230).

The program this month features the following speakers:

  • Kai Lawonn
    • Title – Illustrative Visualization of Medical Data Sets
    • Abstract – The aim of an illustrative visualization method is to provide a simplified representation of a complex scene or object. Concave and convex regions are emphasized and the surface complexity is reduced by omitting unnecessary information. This abstraction is often preferred over fully illuminated scenes in a multitude of applications. This talk presents an overview of the state-of-the-art for feature lines. Additionally, an evaluation is shown to assess the quality of feature lines on anatomical data sets. Based on the evaluation, two conclusions in the field for medical applications were derived. From this point, this talk presents two solutions in the field of illustrative visualization for medical data sets. A novel line drawing technique will be presented to illustrate surfaces. According to different requirements, this technique will be extended for molecular surfaces. In the field of vessel visualization with embedded blood flow, an adaptive visualization method will be introduced. This technique will also be extended to animated blood flow. Finally, this talk shows different illustrative visualization concepts, which can be applied in various fields for depicting surface information.
  • Renata Raidou
    • Title – Test Talk EuroVis2015: Visual Analytics for the Exploration of Tumor Tissue Characteristics
    • Abstract – Tumors are heterogeneous tissues consisting of multiple regions with distinct characteristics. Characterization of these intra-tumor regions, using medical imaging data, can improve patient diagnosis and enable a better targeted treatment. However, the high dimensionality and complexity of the imaging-derived feature space of tumor tissue characteristics is prohibiting for easy exploration and analysis. We propose a visual tool for: (1) easy exploration and visual analysis of the feature space of imaging-derived tissue characteristics and (2) knowledge discovery and hypothesis generation and confirmation, with respect to reference data used in clinical research. We employ, as central view, a 2D embedding of the imaging-derived features. Multiple linked interactive views provide functionality for the exploration and analysis of the local structure of the feature space, enabling linking to patient anatomy and clinical reference data.
  • Kristinn Rúnarsson
    • Title – Animated Photomosaics
    • Abstract – A photomosaic is an image that has been divided into a grid of tiles, each of which is then replaced with another image that matches the tile section best. Animated photomosaics extend the previous photomosaic techniques to support video clips as input. The goal of the project is to come up with image descriptor suitable to generate photomosaics, and an application to efficiently create visually pleasing and coherent animated photomosaics.

As a reminder, all CGV MSc students (both seminar and thesis project) are expected to attend our monthly colloquium series. The next Colloquium is planned on Thursday 18 June. All other interested colleagues are more than welcome, so feel free to disseminate this announcement.

CGV Colloquium – Thursday April 9th

You are cordially invited to attend our next Computer Graphics and Visualization (CGV) Colloquium, which will be held on Thursday April 9, 2015, 15.45-17.20, in the Dijkstraroom (HB09.150). The program this month features the following speakers:

  • Mattijs van Driel:
    • Title – Real time intersections on  Space Scale Cube data
    • Abstract – The space scale cube (SSC) model offers a new way of encoding 2D geographic data with continuous level of abstraction on the Z axis. It lacks a flexible way of visualizing intersections, which is what this work offers at its core. A SSC based dataset is preprocessed into a simple octree structure, which is then used as input for an interactive rendering system that provides a user controllable intersection surface. The system uses the octree structure to cull unnecessary chunks, and OpenGL to render the intersections themselves. In addition to rendering intersections, the approach allows for a number of enhancements on the final image, such as antialiasing and transition colorization.
  • Rob Coorens:
    • Title – Quantification of deformation and sliding of orbital fat during rotation of the eye Short
    • Abstract – When the eye rotates, the muscles contract and move through the orbital fat. This movement is a combination of sliding through the fat and deformation of the fat. The goal of the project is to quantify both types of movement from MRI data of the orbit using registration and segmentation techniques.

As a reminder, all CGV MSc students (both seminar and thesis project) are expected to attend our monthly colloquium series. All other interested colleagues are more than welcome, so feel free to disseminate this announcement. Looking forward to see you all at the colloquium!

Recent PhD defenses

Two new doctors graduated from our group at the end of 2014 in the field of medical visualization:

  • Dr. Peter Kok successfully defended his PhD. In his thesis, ‘Integrative Visualization of Whole Body Molecular Imaging Data‘, Dr. Kok present methods to map molecular imaging data to a common reference frame, to combine multiple modalities and to compare scans taken at different timepoints. The full text of the thesis is available here.
Dr. Kok with his paranymphs and the thesis committee members.
Dr. Kok with his paranymphs and the thesis committee members. tblr: Jos Roerdink, Elmar Eisemann, Charl Botha, Erik Jansen, Boudewijn Lelieveldt, beadle Rina Abbriata, Louise van der Weerd, Bernhard Preim, Noeska Smit, Peter Kok, Thomas Kroes and the head of the committee.
  • On the same day, Dr. Stef Busking also successfully defended his PhD. His thesis, ‘Visualization of Variation and Variability‘ deals with comparative visualization as a means to analyze variation or variability based on two or more specific instances of the data. The full text of the thesis is available here.

We would like to congratulate to both doctors with their accomplishments.

CGV Colloquium – Thursday February 19th

You are cordially invited to attend our next Computer Graphics and Visualization (CGV) Colloquium, which will be held on Thursday February 19, 2015, 15.45-17.20, in the Vassiliadis room (HB10.230).

The program this month features the following speakers:

  • Kevin Allain: Visualizing dynamic networks with matrix cubes
  • Hongjie Lee: Active shape model for facial detection and medical image analysis
  • Panchamy Krishnan: Random forests in X-ray segmentation
  • Jean-Baptiste Doyon: Refinement of lung nodule candidates based on local geometric shape analysis and Laplacian of Gaussian kernels

As a reminder, all CGV MSc students (both seminar and thesis project) are expected to attend our monthly colloquium series. All other interested colleagues are more than welcome, so feel free to disseminate this announcement. Looking forward to see you all at the colloquium!

CGV Colloquium – Wednesday December 16th

You are cordially invited to attend our next Computer Graphics and Visualization (CGV) Colloquium, which will be held *tomorrow* Tuesday, December 16th, 2014, 15.45-17.00, in the Dijkstra room (HB9.150).

The program this month features the following speakers:

  • Vincent Hogendoorn: Image-based façade modeling
  • Antony Löbker: Image completion using large image collections

All interested colleagues are more than welcome, so feel free to disseminate this announcement. As a reminder, all CGV MSc students (both seminar and thesis project) are expected to attend our monthly colloquium series. Looking forward to see you at the colloquium!

CGV Colloquium – Thursday December 11th

We would like to invite you to a special CGV colloquium on the 11th of December at 15:45 – 17:15 (see details below). The colloquium will be held in the Dijkstrazaal (HB 09.150) and will feature two invited talks by guest speakers: 

image003Prof. Dr.-Ing. Bernhard Preim

Title: Visual Analytics in Cohort Study Data

Abstract: Epidemiology aims at understanding relations between life style, genetics, environmental factors and the outbreak of diseases.

Recent large scale cohort studies involving a wealth of sociodemographic data and medical image data bear a great potential to identify complex interactions between different factors and non-linear relations between risk factors and the likelihood and severity of diseases. A combination of data analysis (dimensionality reduction and clustering), image analysis (segmentation and quantification of target structures) and interactive visualization supports the generation of new hypothesis.

As case study, we discuss back pain and its relation to socio-demographic and medical image data. The epidemiological data is part of the SHIP ( http://www.medizin.uni-greifswald.de/cm/fv/english/ship_en.html). 

image005

Prof.dr. Jos Roerdink

Title: Brain Patterns: Prediction of Neurodegenerative Diseases

Abstract: In this talk, I will discuss some recent work on the visualization and analysis of brain patterns obtained from neuroimaging data, and their use in the understanding of brain (mal)functioning.

The recently GLIMPS (“GLucose IMaging in ParkinsonismS”) project at the University of Groningen concerns the creation of a national database of FDG-PET scans which reflect the glucose consumption of the brain in patients with neuro-degenerative diseases. The goal is to identify distinctive structural and functional brain patterns and derived quantities like network patterns of brain activity, which display statistically significant differences in healthy subjects and patients with certain types of neuro-degenerative disease. The database will be used for clinical practice as well as for research purposes. Pattern classification and visualization methods will be developed to associate brain patterns to various types and stages of neuro-degenerative disease. First results will be shown and discussed.

CGV Colloquium – Thursday November 27nd

You are cordially invited to attend our next  Computer Graphics and Visualization (CGV) Colloquium, which will be held on Thursday, November 27, 2014, 15.45-17.00,
in the Vassiliadis room (HB10.230).

The program this month features the following speakers:

  • Kristinn Rúnarsson:  Animosaics
  • Bas Dado:  Sparse voxel directional acyclic graphs for geometry
  • Stefan Ohrhallinger and Mohamed Radwan:  Surface reconstruction from sparsely sampled point clouds

All interested colleagues are more than welcome, so feel free to disseminate this announcement. As a reminder, all CGV MSc students (both seminar and thesis project) are expected to attend our monthly colloquium series. Looking forward to see you all at the colloquium!