WSCG 2014
22nd WSCG International Conference on
Computer Graphics, Visualization and Computer Vision
2014
http://www.wscg.cz
Primavera Hotel & Congress Center
Plzen, Czech Republic
June 2 – 5, 2014
Conference Program
and
ABSTRACTS
Keynote speakers
Manuel M.Oliveira, Universidade Federal do Rio Grande do Sul
Porto Alegre, Brazil
Tino Weinkauf, Max-Planck-Institut für Informatik
Saarbrucken, Germany
Brian A. Barsky, University of California, Berkeley, USA
Conference Chair
Vaclav Skala, University of West Bohemia
Plzen, Czech Republic
Some links might not be valid; especially in the case of Additional files as they have not been submitted correctly or nit submitted.
Time schedule of sessions is available at the last page. Update 2014-05-27
Session: A1
Session: A2
Session: B1
Session: C1
Session: D1
Session: F1
Session: F2
Session: G2
Session: H1
Session: K1
Session: K2
Session: L1
Session: M1
Session: M2
Session: N1
POSTERS
Session: Posters A
Session: Poster B
Weinkauf,T.
Abstract:
The flow map has become a standard tool for the analysis and visualization of
unsteady flows. In simple terms, it maps the start point of a particle
integration to its end point. Flow maps are used to compute Finite Time
Lyapunov Exponents (FTLE), Streak Line Vector Fields, or to speed up other
methods in flow visualization. However, they are very costly in terms of both
computation time and storage. In this talk, I will give an overview of the
latest developments in flow visualization, review the theoretical and practical
benefits of flow maps, discuss issues of accuracy and complexity, and pose open
questions for future research in this area.
Oliveira,M.M.
Abstract:
High-dimensional filtering is a key component for many graphics, image, and
video processing applications. Edge-preserving filters (an important class of
high-dimensional ones), for instance, are essential for tasks like
global-illumination filtering, tone mapping, denoising, detail enhancement, and
non-photorealistic effects, among many others. Edge-preserving filtering can be
implemented as a convolution with a spatially-varying kernel in image space, or
with a spatially-invariant kernel in high-dimensional space. Performing the
operation either way is computationally expensive, preventing its use in
interactive and real-time scenarios. The talk will present two recent
techniques we have developed for efficiently performing edge-aware filtering.
The first one is based on a domain transform that allows high-dimensional
geodesic filtering to be performed in linear time as a sequence of 1-D
filtering steps using a spatially-invariant kernel. The second technique works
by sampling and filtering the input signal using a set of 2-D manifolds adapted
to the original data. Its cost is linear in the number of pixels and in the
dimensionality of the space in which the filter operates. These techniques are
significantly faster than previous approaches, supporting high-dimensional
filtering of images, videos, and global illumination effects in real time. In
the talk, I will present several examples illustrating their use in graphics,
image, and video processing applications.
Barsky,B.
Abstract:
This talk will present research on simulating human vision and on correcting
visual aberrations with computational light field displays . The simulation is
not an abstract model but incorporates real measurements of a particular
individual’s entire optical system. Using these measurements, synthetics images
are generated. This process modifies input images to simulate the appearance of
the scene for the individual. Recent work on vision-correcting displays will
also be briefly introduced. Given the measurements of the optical aberrations
of a user’s eye, a vision correcting display will present a transformed image
that when viewed by this individual will appear in sharp focus. This could
impact computer monitors, laptops, tablets, and mobile phones. Vision
correction could be provided in some cases where spectacles are ineffective.
Gain,J., Marais,P., Neeser,R.
Abstract:
Procedural methods offer an automated means of generating complex cityscapes,
incorporating the placement of park areas and the layout of roads, plots and
buildings. Unfortunately, existing interfaces to procedural city systems tend
to either focus on a single aspect of city layout (such as the road network)
ignoring interaction with other elements (such as building dimensions) or
expect numeric input with little visual feedback, short of the completed city,
which may take up to several minutes to generate. In this paper we present an
interface to procedural city generation, which, through a combination of
sketching and gestural input, enables users to specify different land usage
(parkland, commercial, residential and industrial), and control the geometric attributes
of roads, plots and buildings. Importantly, the inter-relationship of these
elements is pre-visualized so that their impact on the final city layout can be
predicted. Once generated, further editing, for instance shaping the city
skyline or redrawing individual roads, is supported. In general, City Sketching
provides a powerful and intuitive interface for designing complex urban
layouts.
Vaaraniemi,M., Görlich,M., Au,A.
Abstract:
The description of objects in navigation maps by textual annotations provides a
powerful means for orientation and visual data exploration. However, displaying
labels for all features leads to a cluttered map with unreadable labels and
occluded information. Therefore, the overall goal is to display the most
important and filter out the less important labels. In this paper, we present a
general approach for filtering labels. We use the navigation in automotive maps
as an application to test our approach. This involves the creation of a
priority metric for ranking labels in maps. Our flexible system allows runtime
configuration of the priority. Moreover, we keep the temporal coherency of
label filtering; hence, jittering of labels does not occur. The system is
predictable, modular, and can easily be adapted to new applications. On
medium-class hardware, our real-time system is capable of filtering on average
1000 labels within 12 ms. A concluding expert study validates our approach for
navigation purposes. All candidates approve the resulting clear labeling
layout.
Khan,S.D., Vizzari,G., Bandini,S., Basalamah,S.
Abstract:
Urbanisation is growingly generating crowding situations which generate
potential issues for planning and public safety. This paper proposes new
techniques of crowd analysis and precisely crowd flow segmentation and crowd
counting framework for estimating the number of people in each flow segment. We
use two foreground masks, one generated by Horn-Schunck optical flow, used by
crowd flow segmentation, and another by Gaussian background subtraction, used
by crowd counting framework. For crowd flow segmentation, we adopt $K$-means
clustering algorithm which segments the crowd in different flows. After
clustering, some small blobs can appear which are removed by blob absorption
method. After blob absorption, crowd flow is segmented into different dominant
flows. Finally, we estimate the number of people in each flow segment by using
blob analysis and blob size optimization methods. Our experimental results
demonstrate the effectiveness of the proposed method comparing to other
state-of-the-art approaches and our proposed crowd counting framework estimates
the number of people with about 90\% accuracy.
Kenwood,J., Gain,J., Marais,P.
Abstract:
Forested landscapes are an important component of many large virtual
environments in games and film. In order to reduce modelling time, procedural
methods are often used. Unfortunately, procedural tree generation tends to be
slow and resource-intensive for large forests. The main contribution of this
paper is the development of an efficient procedural generation system for the
creation of large forests. Our system uses L-systems, a grammar-based
procedural technique, to generate each tree. We algorithmically modify L-system
tree grammars to intelligently use an instance cache for tree branches. Our
instancing approach not only makes efficient use of memory but also reduces the
visual repetition artifacts which can arise due to the granularity of the
instances. Instances can represent a range of structures, from a single branch
to multiple branches or even an entire tree. Our system improves the speed and
memory requirements for forest generation by 3--4 orders of magnitude over
naive methods: we generate over $1,000,000$ trees in 4.5 seconds, while using
only 350MB of memory.
Reich,W., Kasten,J., Scheuermann,G.
Abstract:
Gauss' theorem, which relates the flow through a surface to the vector field
inside the surface, is an important tool in Flow Visualization. We are exploit
the fact that the theorem can be further refined on polygonal cells and
construct a process that encodes the particle movement through the boundary
facets of these cells using transition matrices. By pure power iteration of
transition matrices, various topological features, such as separation and
invariant sets, can be extracted without having to rely on the classical
techniques, e.g., interpolation, differentiation and numerical streamline
integration. We will apply our method to steady vector fields with a focus on
three dimensions.
Iwao,T., Kubo,H., Maejima,A., Morishima,S.
Abstract:
In this paper, we propose a novel method for animating CG characters that while
walking or running pay heed to obstacles. Here, our primary contribution is to
formulate a generic visuomotor coordination model for obstacle recognition with
whole body movements. In addition, our model easily generates gaze shifts,
which expresses the individuality of characters. Based on experimental
evidence, we also incorporate the coordination of eye movements in response to
obstacle recognition behavior via simple parameters related to the target
position and individuality of the characters's gaze shifts. Our overall model
can generate plausible visuomotor coordinated movements in various scenes by
manipulating parameters of our proposed functions.
Domaradzki,J., Martyn,T.
Abstract:
This paper presents an improved method for simulating melting of ice. The
melting process is implemented as a result of the heat transfer between ice
objects and fluids (water and air). Both the solids and the fluids, includ-ing
air, are modeled as a set of particles with specified temperatures, which can
vary locally during simulation. The proposed new particle-based air model
allows one to consider in simulation the influence of the natural air
convection on the ice melting process. Moreover, the model makes it possible to
melt the ice object in a controllable way by means of external heat sources.
The motion of air and water, originally described by the Navier-Stokes equations
for incompressible fluids, is computed using the Smoothed Particle
Hydrodynamics (SPH) algorithm, which we modify to properly handle our
particle-based air and its interactions with ice and water. Thanks to a
GPU-based implementation, the proposed method allows us to run the simulation
of ice melting at interactive speed on an average PC.
Melo,E., de Amo,S., Guliato,D.
Abstract:
A good accuracy in image retrieval across different visual domains, such as
photos taken over different seasons or lighting conditions, paintings,
drawings, hand-drawn sketches, still is a big challenge. This paper proposes
the use of visual attention to estimate the relative importance of some regions
in a given query image. Recently, researchers used different databases in
specific domains to validate their hypothesis. In this paper, we also propose a
database with multiple image domains, called UFU-DDD. We used the UFU-DDD
database to demonstrate the performance and accuracy gains from the association
of visual attention with orientation-based feature descriptors. The analysis of
the results showed that our approach outperforms all the standard descriptors
used in the experiments. We hope the UFU-DDD database constitutes a valuable
benchmark to the future research in cross-domain similarity searching.
Steinhausen,H.C., den Brok,D., Hullin,M.B., Klein,R.
Abstract:
Most current acquisition setups for bidirectional texture functions (BTFs) are
incapable of capturing large-scale material samples. We propose a method based
on controlled texture synthesis to produce BTFs of appealing visual quality for
such materials. Our approach uses as input data a complete measurement of a
small fraction of the sample, together with few images of the large-scale
structure controlling the synthesis process. We evaluate the applicability of
our approach by reconstructing sparsified ground truth data and investigate the
consequences of choosing different kinds and numbers of constraint images.
den Brok,D., Steinhausen,H. C., Hullin,M., Klein,R.
Abstract:
We propose a simple and efficient method to reconstruct materials' texture
functions (BTFs) from angularly sparse measurements. The key observation is
that materials of similar types exhibit both similar surface structure and
reflectance properties. We exploit this by manually clustering an existing
database of fully measured material BTFs and fitting a linear model to each of
the clusters. The models are computed not on per-texel data but on small
spatial BTF patches we call apparent BTFs. Sparse reconstruction can then be
performed by solving a linear least-squares problem without any regularization,
using a per-cluster sampling strategy derived from the models. We demonstrate
that our method is capable of faithfully reconstructing fully resolved BTFs
from sparse measurements for a wide range of materials.
Popov,E.V., Popova,T.P., Rotkov,S.I.
Abstract:
The paper describes the approximate method of the shortest path finding between
two points on a surface. This problem occurs when generating a cutting pattern
after the form of the fabric tensile surface is found. The shortest path
finding is reduced to the problem of finding the geodesic line on the surface.
However, the numerical problem solution of the form finding of fabric tensile
structure leads to the fact that the final surface is represented by an
arbitrary polyhedron. There is no analytical problem solution of finding
shortest paths in this case. The described method allows finding the shortest
path on a surface of any regular polyhedron form.
Zahradka,J., Barina,D., Zemcik,P.
Abstract:
A novel method for a representation of the optical system distortion using the
discrete wavelet transform is proposed in this paper. Using the presented
approach, virtually any complex distortion can be represented only with a small
number of wavelet coefficients. Moreover, one can represent the distortion up
to the resolution of one pixel or even finer. The experiments shown in the
paper suggest that the introduced wavelet interpolation reconstructs distorted
data very realistically. The proposed method was evaluated on two scenes
comprising a projector and irregular surfaces using dataset of images of
various type.
Cabiddu,D., Attene,M.
Abstract:
We propose a web-based system to remotely and distributedly process triangle
meshes. Users can implement complex geometric procedures by composing simpler
processing tools that, in their turn, can be provided by researchers who
publish them as appropriate Web services. We defined an efficient geometric
data transfer protocol in order to resolve the potential mesh delivery
bottleneck caused by the transfer of large models to the various servers on
typical long-distance connections with limited bandwidth. We have experimented
our system on several large models and on diverse processing scenarios, and we
have concluded that our transfer protocol significantly reduces the overall
time needed to produce the result.
Budak,V., Zheltov,V.
Abstract:
In this article we consider a local estimations of the Monte Carlo method for
solving the equation of the global illumination. The local estimations allow to
calculate directly the luminance at a predetermined point, in a given direction
for an arbitrary law of reflection. Thus, there is no need to construct the map
of the illumination. Thereby it is much more effective than direct modeling or
method of finite element . The usage in lighting calculations of the object
described by the spherical harmonics is also discussed in the article.
Lakshantha,E., Egerton,S.
Abstract:
With robots appearing frequently within our society, the cases will be higher
where people with little or no practical experience in robotics would have to
supervise robots. Future interfaces should make Human Robot Interactions (HRI)
intuitive for such less-experienced users. A key requirement to have an
intuitive interface is to improve the level of HRI performance. In this study
we try to improve the HRI performance by developing a system namely, SHRIMP
(Spatial Human Robot Interaction Marker Platform) based on Augmented Reality
(AR) technology. We present SHRIMP as a new type of middleware for HRI, that
can mediate high-level user intentions with robot-related action tasks. SHRIMP
enables users to embed user intentions in the form of AR diagrams inside the
robot's environment (as seen by the robot's camera view). These AR diagrams
translate into action tasks for robots to follow in that environment.
Furthermore, we report on the HRI performance induced by our SHRIMP framework
when compared to an alternative more common robot control interface, a joystick
controller.
Molchanov,V., Linsen,L.
Abstract:
Numerical simulations in the fields of science and engineering generate spatial
data of time-varying phenomena that frequently depend on various simulation and
input parameters. It is common to run hundreds of simulations to investigate
the dependence of the modeled process on the choice of the parameters. We
propose a comprehensive approach for the visual analysis of such multi-run data
to detect patterns and outliers. We use dimensionality reduction algorithms to
generate a visual representation that exhibits the distribution of the
simulation results under varying parameter settings. Each field (or even multi-field)
of every time step and every simulation run is represented as a point in a 2D
space, where the 2D layout conveys similarity of the scalar fields. Points
corresponding to consecutive time steps of one run are connected by line
segments, such that each simulation run is represented as a polyline.
Consequently, the multi-run data are visually encoded as a set of polylines.
Variations of hue, saturation, opacity, and shape allow for distinguishing
groups of simulations and depicting various characteristics of runs. The user
can interactively change these settings, while further interaction mechanisms
allow for selection, refinement, zooming, requesting textual information, and
brushing and linking to coordinated (or embedded) views of physical and attribute
space visualizations. We apply our approach to two common applications with
significantly different data structure. The first application is a multi-run
climate modeling simulation based on an Eulerian method over a 2D regular grid.
The second application is a multi-run binary star evolution simulation based on
a Lagrangian method (Smoothed Particle Hydrodynamics) with unstructured
particles changing 3D positions over time. We demonstrate the contribution and
impact of our visualization method for the interactive visual analysis of the
multi-run data by identifying meaningful groups of simulations, detecting
global patterns, and finding interesting outliers.
Hast,A., Marchetti,A.
Abstract:
Image features are obtained by using some kind of interest point detector,
which often is based on a symmetric matrix such as the structure tensor or the
Hessian matrix. These features need to be invariant to rotation and to some degree
also to scaling in order to be useful for feature matching in applications such
as image registration. Recently, the spinor tensor has been proposed for edge
detection. It was investigated herein how it also can be used for feature
matching and it will be proven that some simplifications, leading to variations
of the response function based on the tensor, will improve its characteristics.
The result is a set of different approaches that will be compared to the well
known methods using the Hessian and the structure tensor. Most importantly the
invariance when it comes to rotation and scaling will be compared.
Wasenmüller,O., Krolla,B., Michielin,F., Stricker,D.
Abstract:
Within the computer vision community, the reconstruction of rigid 3D objects is
a well known task in current research. Many existing algorithms provide a dense
3D reconstruction of a rigid object from sequences of 2D images. Commonly, an
iterative registration approach is applied for these images, relying on
pairwise dense matches between images, which are then triangulated. To minimize
redundant and imprecisely reconstructed 3D points, we present and evaluate a
new approach, called Correspondence Chaining, to fuse existing dense two-view
3D reconstruction algorithms to a multi-view reconstruction, where each 3D
point is estimated from multiple images. This leads to an enhanced precision
and reduced redundancy. The algorithm is evaluated with three different
representative datasets. With Correspondence Chaining the mean error of the
reconstructed pointclouds related to ground truth data, acquired with a laser
scanner, can be reduced by up to 40%, whereas the root mean square error is
even reduced by up to 56%. The reconstructed 3D models contain much less 3D
points, while keeping details like fine structures, the file size is reduced by
up to 78% and the computation time of the involved parts is decreased by up to
42%.
Liu, Damon Shing-Min Liu, Chang, Te-Li
Abstract:
Here we present an interactive guidance and navigation system that assists user
in acquiring pictures for image based 3D modeling. To reconstruct an object‘s
3D model, user follows our instruction to take a set of images for an object in
different angles, we calculate their relative viewing positions and spare point
cloud data using structure from motion technique. After we obtain sufficient
number of images, we use Patch-based Multi-View Stereo (PMVS) [1] software to
generate dense point cloud data. When displaying dense point cloud, we provide
user an interface to eliminate those noise data points yielded from background
construction or re-projection errors. Afterwards we reconstruct surface mesh as
output. Our system provides informative message for failures while calculating
camera poses and helps user how to resolve those problems. Furthermore, we
assess the quality of camera poses reconstruction and generated point cloud to
reveal the lack of angles for captured images and guide user to remedy those
information.
Zeller,N., Quint,F., Guan,L.
Abstract:
This paper presents a novel system for 3D scene reconstruction and obstacle
detection for visually impaired people, which is based on Microsoft Kinect.
From the depth image of Kinect a 3D point cloud is calculated. By using both,
the depth image and the point cloud a gradient and RANSAC based plane
segmentation algorithm is applied. After the segmentation the planes are
combined to objects based on their intersecting edges. For each object a cuboid
shaped bounding box is calculated. Based on experiments the accuracy of the
presented system is evaluated. The achieved accuracy is in the range of few
centimeters and thus sufficient for obstacle detection. Besides, the paper
gives an overview about already existing navigation aids for visually impaired
people and the presented system is compared to a state of the art system.
Shekow,M., Oppermann,L.
Abstract:
Depth sensor data is commonly used as the basis for Natural User Interfaces
(NUI). The recent availability of different camera systems at affordable prices
has caused a significant uptake in the research community, e.g. for building
hand-pose or gesture-based controls in various scenarios and with different
algorithms. The limited resolution and noise of the utilized cameras naturally
puts a constraint on the distance between camera and user at which a meaningful
interaction can still be designed for. We therefore conducted extensive
accuracy experiments to explore the maximum distance that allows for
recognizing finger-tips of an average-sized hand using three popular depth
cameras (SwissRanger SR4000, Microsoft Kinect for Windows and the Alpha
Development Kit of the Kinect for Windows 2), two geometric algorithms and a
manual image analysis. In our experiment, the palm faces the sensors with all
five fingers extended. It is moved at distances of 0.5 to 3.5 meters from the
sensor. Quantitative data is collected regarding the number of recognized
finger-tips for each sensor, using two algorithms. For qualitative analysis,
samples of the hand outline are also collected. The quantitative results proved
to be inconclusive due to false positives or negatives caused by noise. In turn
our qualitative analysis, achieved by inspecting the hand outline images
manually, provides conclusive understanding of the depth data quality. We find
that recognition works reliably up to 1.5 m (SR4000, Kinect) and 2.4 m (Kinect
2). These insights are generally applicable for designing NUIs that rely on
depth sensor data.
Xing,T., Yang,Y., Yu,Y., Zhou,Y., Xing,X., Du,S.
Abstract:
We introduce a 3D morphing method which generates a merged model given a series
of triangle meshes. Our morphing, based on a set of parameters between the
source and target shapes, can show the process of the transformation from the
source to the target smoothly. We choose a model as our reference mesh, and
obtain corresponding unified models from other models which may have different
number of vertices or facets. Given these unified models, parameters between
any two meshes can be computed integrally or separately for each rigid part.
Different forms of combination of the parameters can generate different merged
models. To address the collapsed situation happened occasionally, shape and
pose morphing are separated for some parts in our work. By merging different
parts of different models, we can get a merged shape, e.g. an animal with the
horse head and the cat body. As an application of our 3D morphing method,
quantifying the difference between any two models can be done efficiently,
represented by the distance between any two sets of low-dimensional parameters
reduced from the initial parameters using Principal Component Analysis (PCA).
Character replacement and model driven are another two applications. Characters
in two-dimensional images are used to guide our morphing work and depth image
sequence is used to drive our merged model to show the same pose as the
character in the sequence respectively.
Vergeest,J.S.M.
Abstract:
Microscopic car-following models are widely used to generate traffic flow
simulations. In some cases visualization on macroscopic scales (both spatial
and temporal) are required to provide relevant feedback to researchers. Recent
studies have indicated that the life time of highway traffic jams is severally
influenced by temporary deviations of the driving style of individual
motorists. The most influential parameters are the longitudinal acceleration
and the headway distance produced by car drivers soon after leaving a
congestion situation. To study the effects of acceleration profiles on the life
times of congestions it is crucial to generate traffic flow simulations which can
be viewed at highly varying spatial and temporal scales. The influence of
adaptive cruise control (ACC), for example, is one of the factors that can be
forecasted using traffic flow simulations. In this paper we present typical
results of such simulations and suitable graphical presentations, which support
the traffic flow research.
Shahabi Lotfabadi,M., Shiratuddin,M.F., Wong,K.W.
Abstract:
In this paper Fuzzy Rough Set is used for feature selection in the Content
Based Image Retrieval system. Noisy query images are fed to this Content Based
Image Retrieval system and the results are compared with four other feature
selection methods. The four other feature selection methods are Genetic
Algorithm, Information Gain, OneR and Principle Component Analysis. The main
objective of this paper is to evaluate the rules which are extracted from fuzzy
rough set and determine whether these rules which are used for training the
Support Vector Machine can deal with noisy query images as well as the original
queried images. To evaluate the Fuzzy Rough set feature selection, we use 10
sematic group images from COREL database which we have purposely placed some
defect by adding Gaussian, Poisson and Salt and Pepper noises of different
magnitudes. As a result, the proposed method performed better in term of
accuracies in most of the different types of noise when compared to the other
four feature selection methods.
Sablina,V.A., Novikov,A.I., Nikiforov,M.B., Loginov,A.A.
Abstract:
The problem of determining precisely the current location coordinates and
orientation of an aircraft in the space is formulated and considered in this
paper. The review of the existing approaches to the navigation tasks solutions
in the aviation is done. The advantages of the contour analysis and the
multiple view geometry mathematical apparatus application are revealed. The
general navigation parameters correction technique on the basis of the
multispectral computer vision system images analysis is suggested. For the main
stages of the suggested technique the used approaches are described and the experimental
results of the investigations are obtained, viz. the object detection and
comparison, the geometric interconnection finding between the images for the
subsequent navigation parameters correction. The obtained results also can be
used for the real and the synthetized images superimposition problem solution
in multispectral computer vision systems. The experiments show that using
multiple view geometry methods in combination with contour analysis methods is
promising for the aircraft navigation parameters correction problem solution in
the real time.
Ionescu,R.T., Popescu,A.L., Popescu,M.
Abstract:
Computer vision researchers have developed various learning methods based on
the bag of words model for image related tasks, including image categorization,
image retrieval and texture classification. In this model, images are
represented as histograms of visual words (or textons) from a vocabulary that
is obtained by clustering local image descriptors. Next, a classifier is
trained on the data. Most often, the learning method is a kernel-based one.
Various kernels can be plugged in to the kernel method. Popular choices,
besides the linear kernel, are the intersection, the Hellinger‘s, the
χ2 and the Jensen-Shannon kernels. Recent object recognition results
indicate that the novel PQ kernel seems to improve the accuracy over most of
the state of the art kernels. The PQ kernel is inspired from a set of rank
correlation statistics specific for ordinal data, that are based on counting
concordant and discordant pairs among two variables. In this paper, the PQ
kernel is used for the first time for the task of texture classification. The
PQ kernel is computed in O(nlogn) time using an efficient algorithm based on
merge sort. The algorithm leverages the use of the PQ kernel for large
vocabularies. Texture classification experiments are conducted to compare the
PQ kernel with other state of the art kernels on two benchmark data sets of
texture images. The PQ kernel has the best accuracy on both data sets. In terms
of time, the PQ kernel becomes comparable with the state of the art
Jensen-Shannon kernel. In conclusion, the PQ kernel can be used to obtain a
better pairwise similarity between histograms, which, in turn, improves the
texture classification accuracy.
Masmoudi,I., Wali,A., Alimi,A.
Abstract:
Intelligent systems for vacant parking spaces detection present an important
solution to facilitate finding an available place for the drivers. Many real
world challenges can face these vision based systems like weather conditions
and luminance variation. In this paper, we are interested in the problem of
inter spaces occlusion, where one or more place of a parking can be hidden by
another parked vehicle. In order to overcome this problem we propose a new
on-street surface based model for parking model extraction and we perform
vehicle tracking in order to detect the events of "Entering" and "Leaving"
of a car to a parking place.
Hutter,M., Knuth,M., Kuijper,A.
Abstract:
We present a method for partitioning meshes that allows a simple and efficient
parallel implementation of different simulation methods. It is based on a
generalization of the concept of independent sets from graph theory to sets of
simulation elements. The general description makes it versatile and flexibly
applicable in existing simulation systems. Every simulation method that formerly
worked by sequentially processing a set of simulation elements can now be
parallelized by partitioning the underlying set, without affecting the behavior
of the simulated model.
Velas,M., Spanel,M., Materna,Z., Herout,A.
Abstract:
Calibration of the LiDAR sensor with RGB camera finds its usage in many
application fields from enhancing image classification to the environment
perception and mapping. This paper presents a pipeline for mutual pose and orientation
estimation of the mentioned sensors using a coarse to fine approach. Previously
published methods use multiple views of a known chessboard marker for computing
the calibration parameters, or they are limited to the calibration of the
sensors with a small mutual displacement only. Our approach presents a novel
$3$D marker for coarse calibration which can be robustly detected in both the
camera image and the LiDAR scan. It also requires only a single pair of
camera-LiDAR frames for estimating large sensors displacement. Consequent
refinement step searches for more accurate calibration in small subspace of
calibration parameters. The paper also presents a novel way for evaluation of
the calibration precision using projection error.
Nanni,L., Costa,Y., Brahnam,S.
Abstract:
This paper presents a comparison among different texture descriptors and
ensembles of descriptors for music genre classification. The features are
extracted from the spectrogram calculated starting from the audio signal. The
best results are obtained by extracting features from subwindows taken from the
entire spectrogram by Mel scale zoning. To assess the performance of our
method, two different databases are used: the Latin Music Database (LMD) and
the ISMIR 2004 database. The best descriptors proposed in this work greatly
outperform previous results using texture descriptors on both databases: we
obtain 86.1% accuracy with LMD and 82.9% accuracy with ISMIR 2004. Our descriptors
and the MATLAB code for all experiments reported in this paper will be
available at https://www.dei.unipd.it/node/2357.
Krolla,B., Gava,C., Pagani,A., Stricker,D.
Abstract:
In this work, we discuss and evaluate the reliability of first order
uncertainty propagation in context of spherical Structure from Motion,
concluding that they are not valid without restrictions, but depend on the
choice of the objective function. We furthermore show that the choice of the
widely used geodesic error as objective function for a reprojection error
optimization leads to disproportional pose uncertainty results of spherical
cameras. This work identifies and outlines alternative objective functions to
bypass those obstacles by deducing Jacobian matrices according to the chosen
objective functions with subsequent conduction of first order uncertainty
propagation. We evaluate the performance of the different objective functions
in different optimization scenarios and show that best results for uncertainty
propagation are obtained using the Euclidean distance to measure deviations of
image points on the spherical image.
Trouvain,G., Gagnol,V., Duc,E., Sancho,J.F.
Abstract:
In computer graphics and in industrial context, Mass-Spring model is used to
obtain fast and visual results in physical simulations. A disadvantage of the
method is to obtain accurate result on account of the difficulty to define
parameters of a Mass-Spring Model. Different works and results are carried out
to define Mass-Spring parameters in other domains such as in cloth animation or
in soft tissue modeling. However the Mass-Spring model is not used in some
context where a real-time computation can be useful as in tire manufacturing
industry for example. In this paper, a method is presented to define the
geometric configuration of a Mass-Spring system and the tuning of the mass,
stiffness and damper parameters according to physical material behaviours.
Different load cases are studied and used to conduct a sensitivity study on the
network spring parameters. Then, results are compared to Finite Element Model
of same cases in order to evaluate the precision of the proposed approach.
Leach,C., Marais,P.
Abstract:
We describe a system that is able to efficiently render large-scale
particle-based granular terrains in real-time. This is achieved by integrating
a particle-based granular terrain simulation with a heightfield-based terrain
system, effectively creating a level of detail system. By quickly converting
areas of terrain from the heightfield-based representation to the
particle-based representation around dynamic objects which collide with the
terrain, we are able to create the appearance of a large-scale particle-based
granular terrain, whilst maintaining real-time frame rates.
Li,A., Kou,F., Niu,Q., Tian,H.
Abstract:
As a rule, an energy method is widely adopted for b-spline curve smoothing, but
this method has the disadvantages such as massive calculation, computation complexity
and low efficiency. Compared with the energy method, multi-resolution smoothing
approaches nicely overcome these obstacles. Presently, some researches have
been conducted on multi-resolution smoothing, but these efforts mainly aimed at
uniform or quasi-uniform b-spline curves. Uniform and quasi-uniform b-spline
curves are just exceptional cases of NURBS curves. Multi-resolution smoothing
for these types of curves mostly depend on uniform b-spline wavelets, so this
smoothing method can‘t be directly applied to NURBS curves. In this paper,
firstly, new non-uniform b-spline wavelets are created based on discrete
b-spline basis functions in the light of the particularities of NURBS curves,
the wavelet reconstruction and decomposition algorithms are provided. The
wavelets, obviously, have greater flexibility and applicability than uniform
b-spline wavelets because of its distance-independence of neighbor nodes in
knot vectors. Then, it presents the multi-resolution smoothing method for NURBS
curves based on the newly built wavelets. Lastly, an example is presented to
confirm effectiveness of this multi-resolution smoothing method. Furthermore,
the method can also be applied to NURBS surfaces if extended properly.
Pui, S.T., Minoi, JL., Terrin, L., Oliveira, J.F., Gillies, D.F
Abstract:
The standard starting point for the extraction of information from human face
image data is the detection of key anatomical landmarks, which is a vital
initial stage for several applications, such as face recognition, facial
analysis and synthesis. Locating facial landmarks in images is an important
task in image processing and detecting it automatically still remains
challenging. The appearance of facial landmarks may vary tremendously due to
facial variations. Detecting and extracting landmarks from raw face data is
usually done manually by trained and experienced scientists or clinicians, and
the landmarking is a laborious process. Hence, we aim to develop methods to
automate as much as possible the process of landmarking facial features. In
this paper, we present and discuss our new automatic landmarking method on face
data using 2.5-dimensional (2.5D) range images. We applied the Scale-invariant
Feature Transform (SIFT) method to extract feature vectors and the Otsu‘s
method to obtain a general threshold value for landmark localisation. We have
also developed an interactive tool to ease the visualisation of the overall
landmarking process. The interactive visualization tool has a function which
allows users to adjust and explore the threshold values for further analysis,
thus enabling one to determine the threshold values for the detection and
extraction of important keypoints or/and regions of facial features that are
suitable to be used later automatically with new datasets with the same
controlled lighting and pose restrictions. We measured the accuracy of the
automatic landmarking versus manual landmarking and found the differences to be
marginal. This paper describes our own implementation of the SIFT and Otsu‘s
algorithms, analyzes the results of the landmark detection, and highlights
future work.
Barbato, D.
Abstract:
More and more often the design engineers are in the necessity to realize
planning graphic arts loads of information in a very short time: on the one
hand the clients' request, on the other hand the decision-makers forced,
therefore, to considerable conceptual and executive efforts. The increase of
the representative quality and the time and price reduction are just a few of
the 'enemies' against which the stakeholders in the construction industry are
compelled to fight. The three-dimensional models, conceptual and
photo-realistic render, videos, etc., represent a part of the infographics
representations available and required by the market. Pursuant to the
sectorialization of the specific professional skills, the Building Information
Modeling, if properly implemented, deploys itself as 'ally' to face the
interdisciplinary inefficiencies in building projects and to reduce the
planning time without affecting its quality. It must pay attention to the
evolution of the information and data's exchange and management techniques that
constitute a complex project. With this contribution we are going to analyze
the level of interoperability between three BIM software ArchiCAD 16 by
Graphisoft, Revit Architecture 2013 and Robot Structural Analysis both by
Autodesk confirming the compatibility of data exchange and, if necessary, how
to proceed in the case of loss of information in the transition from one software
to another. In particular the Graphisoft program will be used for the
architectural modeling, Revit Architecture as control software of the BIM
management project and finally Robot Structural Analysis for the structural
analysis of the frames in the realized building.
Lawlor,O., Genetti,J.
Abstract:
Just as image data compression is designed to save space while preserving the
essence of an image, we present an adaptive pyramidal rendering scheme designed
to save rendering time while maintaining acceptable image quality. Our
coarse-to-fine scheme predicts when and where it is safe to take less than one
sample per output pixel, and exploits spatial redundancy to predict pixel colors
in the resulting gaps, both of which can be performed at framerate in realtime
on a modern GPU. As a lossy compression method, we present experimental data on
the rendering time versus image quality tradeoff for several example renderers.
Feng Yang, Kuang Fu, Ai Zhou
Abstract:
This paper suggests one method to process fMRI time series based on Bayesian
inference for group analysis. The method is based on Bayesian inference to
divide group into multilevel by session, subject and group levels. It compares
covariance to select prior to reinforce posterior probability in group
analysis. At the same time it combines classical statistics, i.e., t-statistics
to obtain voxel activation at subject level as prior for Bayesian inference at
group level. Through the method, it can effectively decrease computation
expensive and reduce complexity. Therefore the experimental results show robust
on Bayesian inference for group analysis.
Matveev, Yu., Kukharev, G., Shchegoleva, N.
Abstract:
In this paper we propose a simple method for generating standard type linear
barcodes from facial images. The method uses the difference in gradients of
image brightness. It involves averaging the gradients into a limited number of
intervals, quantization of the results into the range of decimal numbers from 0
to 9, and table conversion into the final barcode. The proposed solution is
computationally low-cost and does not require the use of any specialized image
processing software, which makes it possible to generate facial barcodes in
mobile systems. Results of tests conducted on the Face94 database and a
database of composite faces at different ages show that the proposed method is
a new solution for use in real-world practice. It ensures the stability of the
generated barcodes against changes of scale, pose and mirroring of facial
images, as well as changes of facial expressions and shadows on faces from
local lighting.
Wu,F., Dellinger,A.
Abstract:
A GPU-based visualization approach is presented to show the discrepancies
between the 3D model and the fabrication of that model. To show the
differences, a 3D scanner is constructed to scan the fabrication for comparison
with the 3D model. To compare the detailed differences, a high resolution
camera with a projector is used. To demonstrate its application, a sculpting
assistance system is implemented. The system can capture the three-dimensional
model iteratively and provide information by rendering different colors on the
surface to show the topological and geometric differences between the final
target model and the current model. Then the user can see how to modify the
current model to best approximate the final target model. The topological
difference is obtained by rendering on the screen the 3D data from both the
final target model and the current model. The user can manipulate and observe
their differences. The local geometry is compared in the GPU and rendered on
the real scene. Users can easily see the geometry directly on the fabrication.
To keep a fixed relationship between the 3D model and the fabrication, a
reference image is tracked at the bottom stage to recover the related
transformation.
Zhang,Z., McInerney,T., Zhang,N., Guan,L.
Abstract:
3D city models have greatly changed the way we interactive with geographic
information. However both the visualization and interaction are limited on
conventional 2D displays. This paper presents a system that visualizes 3D
cities and allows gesture interaction in the fully immersive Cave Automatic
Virtual Environment (CAVE). The proposed system enables navigation, selection,
and object manipulation, which will be basic functions in applications such as
urban planning, virtual tourism, etc. We propose the use of pattern recognition
methods for gesture recognition as new type of interactions in a Virtual
Reality (VR) environment. In this work, we apply the Hidden Markov Model, to
facilitate real time dynamic gesture recognition, and achieve good recognition
result. We also propose a novel selection method for selecting multiple objects
in VR. User study shows preference of the proposed system both for its
realistic immersive visualization and natural gesture interface.
De Martino,J. M., Angare,L.M.G.
Abstract:
Three-dimensional animation is an area in vast expansion due to, continuous
research in the field has enabled an increasing number of users access to
powerful tools with intuitive interfaces. We present our work-in-progress
methodology by which artists can manipulate existing animation segments using
intuitive characteristics instead of manually changing keyframes' values and
interpolations. To achieve this goal, motion capture is used to create a
database in which actors perform the same movement with different
characteristics; keyframes from those movements are analyzed and used to create
a transformation of animation curves that describe differences of values and
times in keyframes of neutral and a movement with a specific characteristic.
This transformation can be used to change a large set of keyframes, embedding a
desired characteristic into the segment. To test our methodology, we used as a
proof of concept a character performing a walk, represented by 59 joints with
172 degrees of freedom (DOF), and a set of 12 physical and emotional
characteristics. Using our methodology we embedded a neutral walk with these
desired characteristics and evaluated the results with a survey comparing our
modified animations with direct motion capture movements, with partial results.
With this methodology, one can decrease drastically the time needed to tweak
large sets of keyframes, embedding a desired characteristic in a fashion more
closely related to the artistic universe of animators than the mathematical
representations of angles, translations and interpolations in animation curves
commonly used in commercial softwares.
Hordemann,G., Lee,J.K., Smith,A.H.
Abstract:
This paper introduces the development of a new GPU-based database to accelerate
data retrieval. The main goal is to explore new ways of handling complex data
types and managing data and workloads in massively parallel databases. This
paper presents three novel innovations to create an efficient virtual database
engine that executes the majority of database operations directly on the GPU.
The GPU database executes a subset of SQLite‘s SELECT queries, which are
typically the most computationally expensive operations in a transactional
database. This database engine extends existing research by exploring methods
of table caching on the GPU, handling irregular and complex data types, and
executing multiple table joins and managing the resulting workload on the GPU.
The GPU database discussed in this paper is implemented on a consumer grade GPU
to demonstrate the high-performance computing benefits of relatively
inexpensive hardware. Advances are compared both to existing CPU standards and
to alternate implementations of the GPU database.
Gosseaume,J., Kpalma,K., Ronsin,J.
Abstract:
We propose original metrics for estimation of detection and identification of
an object in an image. SAMI, (SAliency based Metrics of Identification), allows
to compare the performance of detection and identification of a given Region Of
Interest (ROI) within a test image. The metrics give a saliency score and a
structural score, for the detection evaluation and the identification
evaluation, respectively, for this ROI. The identification evaluation requires
the ground truth edges of the test image. SAMI has initially been conceived to
estimate the performance of SCOTT, a "Synthesis COncealment Two-level
Texture" algorithm. However, a direct derived application of such metrics
could be the evaluation of saliency algorithms for object segmentation: given
the ground truth area of a salient object in the ROI, the best segmentation
would be the one with the highest SAMI saliency score in this ROI. Another
possible application could be the use of SAMI inside a saliency algorithm, to
compute a dense modified saliency map, in which each pixel has the SAMI score
corresponding to its neigborhood. Such a resulting map would be more robust to
saliency noise from small spots.
Iwaszenko S., Nurzyńska K.
Abstract:
This paper presents the aspects of 3D graphics utilization in the visualization
of underground coal gasification (UCG) process. Data gathered during the
process as well as achieved by the mathematical modelling describe a three
dimensional structure of the georeactor where the process takes place. Proper
visualization of this information is crucial for better understanding of the
process and further possibilities of its development and practical usage.
Therefore, a dedicated software tool was developed to support the visualization
of the data. This program enables visualization of the data in user friendly
environment which supports the monitoring of process during each stage. It is
developed with application of XNA technology in C#.NET. The system overview
with possible applications are presented.
Hwang,S., Choi,Y.
Abstract:
Study of robot that mimics the behavior of small animals such as lizards and
arthropods has been actively carried out. However, research on systematic
analysis of the gait behavior of small animals is not easy to find. Motion
analysis of most living creatures is using the optical motion capture system.
However, it is inapplicable to small animals because of it is difficult to
attach optical makers. To solve this problem, the markerless motion capture is
being researched, but many researches about markerless motion capture performed
with human subjects. Therefore, to apply markerless motion capture system for
insects which have many legs and high degree of freedom, the additional
researches are needed. The purpose of the study is to develop a system to
estimate continuous pose of small articulated animals using three-dimensional
skeleton model of the animal from multi-view video sequence. It includes
extraction of extremity and root of each leg and calculation of joint kinematics
using FABRIK(Forward And Backward Reaching Inverse Kinematics) algorithm with
extracted extremity and root. The method developed in this study will
contribute to better understand gait behavior of the small articulated animals.
Papapavlou,C., Moustakas,K.
Abstract:
In this paper we present a new approach in producing realistic saccade eye
movement animations by incorporating anatomical details of the oculomotor
system into the dynamics of the eye model. Unlike abstract models of the eye
motor behaviour, we make use of a biomedical framework to effectively model the
eye globe along with the three extraocular muscle pairs in efficient detail,
that the application of the corresponding muscle activation signals, naturally
results in realistic motions. That way, we avoid the need of explicitly
providing trajectory information, and therefore simplify the process of eye
animation. Regarding the calculations of the muscle activation signals needed
to drive the animation in a way that imitates a real human eye, we are based on
existing knowledge about the way that the nervous system utilizes the
extraocular muscles during saccades.
Kortelainen,J.M., Antila,K., Schmitt,A., Mougenot,C., Ehnholm,G., Chopra,R.
Abstract:
Semi-automatic segmentation of the prostate boundary is presented for the
pre-operational images of the MRI-guided ultrasonic thermal therapy of the
prostate cancer. The specific deformable surface method is based on firstly
fitting an ellipsoid on the given manual landmark points, then modifying the
shape of the initialization surface mesh by masking out the regions of the
separately segmented bladder and rectum, and finally adapting the surface mesh
by searching image for the edge boundaries in the direction of the surface
normal. The suggested segmentation method combines information from two types
of pre-operational MR-images showing different contrast for the tissue
structure. Dice similarity coefficient (DSC) between the semi-automatic
segmentation and the manual reference was on average 0.89 for a group of N=5
patients having the MRI guided ultrasound thermal treatment. The robustness of
the surface fitting method was tested by simulating 30 randomized
initialization sets of the landmark points for each patient, and the resulting
standard deviation of DSC was 0.01.
Son,J., Choi,Y., Lee,W.S., Kim,S.W.
Abstract:
In this paper, we proposed a new 3D blood vessel modeling method for
FSI(Fluid-Structure Interaction) analysis. Because of characteristics of
medical images, a 3D blood vessel model including intima and adventitia cannot
be reconstructed using a single medical image. For obtain detail intima and
adventitia information, many researchers use IVUS(Intravascular Ultrasound)
image and for calculate position and orientation of IVUS images, X-ray
angiogram images are used. Therefore, by combining these medical images, 3D
blood vessel model can be generated. However, when IVUS image is taken, a
catheter attached miniaturized ultrasound device is inserted into blood vessel,
so the shape of blood vessel is deformed. Accordingly, the 3D blood vessel
model combining IVUS and X-ray angiogram images is in deformed state by IVUS
catheter. For solve this problem, in this study, we proposed novel method for 3D
blood vessel model including undeformed intima and adventitia by IVUS catheter.
Peláez,G., García,F., Armingol,J. Escalera,A.
Abstract:
A solution for driver monitoring and event detection based on 3D information
from a range imaging camera is presented: The system combines 2D and 3D
algorithms to provide head pose estimation and regions of interest
identification. Starting with the captured cloud of 3D points from the sensor and
the detection of a face in the 2D projection of it, the points that correspond
to the head are determined and extracted for further analysis. Later the head
pose estimation with 3 degrees of freedom (Euler angles) is estimated using ICP
algorithm. As a final step, the important regions of the face are identified
and used for further experimentation, e.g. gaze orientation, behavior analysis
and more. The resulting application is a complete 3D driver monitoring
application, based on low cost sensor; it is described how to combine both 2D
and 3D computer vision algorithms for future human factors research enabling
the possibility to study specific factors like driver drowsiness, gaze
orientation or the head pose estimation itself. The experimental results shown
are compared with ground-truth head movements obtained using an IMU
Aristidou,K., Michael,D.
Abstract:
We present a prototype of a diving simulator system that can be used for
organizing dives in real conditions. Our simulator comprises of (a) an accurate
visualization of a real wreck site in Mediterranean sea, Zenobia Cyprus, one of
the most well-known wrecks worldwide and (b) visualization of marine life based
on the real types of species that are gathering near the wreck. Moreover, a
first attempt of integrating an existing diving computation algorithm has been
made. The simulator's purpose, in its complete framework, is to be used by
divers to organize their dives in advance at the specific wreck and moreover to
be used as a tool to promote diving tourism. The diving computation part of the
simulator has been validated according to the Professional Association of
Diving Instructor's data, while the complete prototype of the system has been
evaluated by expert users (divers) denoting the importance of the specific
simulator.
Mahiddine,A., Merad,D., Drap,P., Boi,J.-M.
Abstract:
The registration of two 3D point clouds is an essential step in many
applications. The objective of our work is to estimate the best geometric
transformation to merge two point clouds obtained from different sensors. In
this paper, we present a new approach for feature extraction which is
distinguished by the nature of the extracted signature of each point. The
descriptor we propose is invariant to rotation and overcomes the problem of
multi-resolution. To validate our approach, we have tested on synthetic data
and we have applied to heterogeneous real data.
Lebiedz,J., Mazikowski,A.
Abstract:
The paper presents results of the work concerning the technical specification
of Immersive 3D Visualization Laboratory to be opened in late summer 2014 at
the Faculty of Electronics, Telecommunications and Informatics at Gdańsk
University of Technology in Poland. The person immersed in VR space will be
placed in a transparent sphere with a diameter of over 10 feet, supported on
rollers and equipped with a motion tracking system. Walking motion of the
person will inflict the revolution of the sphere and trigger changes in the
computer generated images on screens surrounding the sphere (CAVE with six
walls) thus creating an illusion of motion. The projection system will be
equipped with a 3D visualization capability and supplemented with a spatial
sound generation system. The analysis prior to the specification was based on
extended studies including literature and site visits to selected installations
in Europe as well as consulting with companies which are leading European
manufacturers and 3D systems integrators.
Pulido,R., Paulano,F., Jiménez, Juan,J.
Abstract:
Visualization and interaction with 3D bone models reconstructed from medical
images are fundamental for bio-medical applications. They are useful for
surgeons in order to diagnose and plan surgical operations. Although
traditional reconstruction techniques based on isosurfacing are mainly used for
visualization, it is desirable to obtain labelled models without outliers in
order to improve the interaction. This paper presents the integration of
digital image processing and computer graphics techniques to enable not only
the reconstruction of simplified 3D bone models, but also the interaction with
them. To that end, the segmentation of CT images is performed in order to
obtain different bone regions and to label them. This approach is divided into
three main parts: segmentation, reconstruction and interaction. The goal of the
segmentation is to extract closed contours and to generate labelled regions
which represent the bone structures to be reconstructed. Then,
three-dimensional bone models are obtained from these regions by isosurfacing.
Finally, a detailed collision detection can be calculated between the 3D models
in the scene in order to provide visual aid when the user is interacting with
them. This interaction includes the calculation of distances, nearest points
and overlapping triangles. Moreover, an immersive experience is provided by
integrating the Leonar3Do stereo system.
Bernard,J., Sessler,D., Ruppert,T., Davey,J., Kuijper,A., Kohlhammer,J.
Abstract:
The definition of similarity between data objects plays a key role in many
analytical systems. The process of similarity definition comprises several
challenges as three main problems occur: different stakeholders, mixeddata, and
changing requirements. Firstly, in many applications the developers of the
analytical system (data scientists) model the similarity, while the users
(domain experts) have distinct (mental) similarity notions. Secondly, the
definition of similarity for mixed data types is challenging. Thirdly, many
systems use static similarity models that cannot adapt to changing data or user
needs. We present a concept for the visual-interactive definition of similarity
for mixed data objects emphasizing 15 crucial steps for the development of
appropriate systems. For each step different design considerations and
implementation variants are presented, revealing a tremendous design space.
Moreover, we present a first implementation of our concept, enabling domain
experts to express mental similarity notions through a visual-interactive
system. An additional system mode enables data scientists to monitor this
similarity-based expert feedback and thereby to validate our implementation.
The provided implementation tackles the different stakeholders problem, the
mixed data problem, and the changing requirements problem. We show the
applicability of our implementation in a case study where a mental similarity
notion is transfered into a functional similarity model.
Fens,P., Funk,M.
Abstract:
In this paper we focus on universal human values as defined by Schwartz
[Schw92] in the context of visualizing personal health data. Can data
visualizations convey human values? We have explored various modalities of
presenting health data and found that personal health visualizations indeed can
convey values. This is currently work in progress, an initial step towards
value-based design in the area of data visualization of personal health data.
Mohamed Alkalai
Abstract:
While much work has been done on table recognition this research has been
primarily concerned with tables in ordinary text. However, tables containing
mathematical structures can differ quite significantly from ordinary text
tables and therefore specialist treatment is often necessary. In fact, it is
even difficult to clearly distinguish table recognition in mathematics from
layout analysis of mathematical formulae. This blurring is often leading to a
number of possible, equally valid interpretations. However, a reliable
understanding of the layout of a formula is often a necessary prerequisite to
further semantic interpretation. In this paper, a new construction of table
representation method is introduced which, attempts to overcome the unsolved
issues mentioned in several published works. This encompasses the lack of sufficient
work that deals with tables with misaligned cells. I utilise multi spatial
relationships between cells to recognise tabular components. Experimental
evaluation on two different datasets shows a promising results.
Brener,N., Harhad,F., Karki,B., Benger,W., Acharya,S., Ritter,M., Iyengar,S.
Abstract:
We present a method to compute and visualize the curvature and torsion scalar
fields derived from a vector field defined on a multi-block curvilinear grid.
In order to compute the curvature and torsion fields, we define a uniform
Cartesian grid of points in the volume occupied by the curvilinear grid and
interpolate from the curvilinear grid to the Cartesian grid to get the vector
field at the Cartesian grid points. We can then use finite difference formulas
to numerically compute the derivatives needed in the curvature and torsion
formulas. Once the curvature and torsion have been computed at the Cartesian
grid points, we employ a multi scale color coding technique to visualize these
scalar fields in orthoslices of the Cartesian grid. This multi scale technique
allows one to observe the entire range of values of the scalar field, including
small, medium and large values. In contrast, if uniform color coding is used to
visualize curvature and torsion fields, it sometimes shows most of the values
in a single predominant color, which makes it impossible to distinguish between
the small, medium and large values. As an example of this multi-scale
technique, we displayed the curvature and torsion fields in a computational
fluid dynamics (CFD) simulation of an industrial stirred tank and used these
images to identify regions of low, medium and high fluid mixing in the tank.
Walha,R., Drira,F., Lebourgeois,F., Garcia,C., Alimi,A.M.
Abstract:
Pattern clustering is an important data analysis process useful in a wide
spectrum of computer vision applications. In addition to choosing the
appropriate clustering methods, particular attention should be paid to the
choice of the features describing patterns in order to improve the clustering
performance. This paper presents a novel feature descriptor, referred as
Histogram of Structure Tensors (HoST), allowing to capture the local
information of an image. The basic idea is that a local pattern could be
described by the distribution of the structure tensors orientations and shapes.
The proposed HoST descriptor has two major advantages. On the first hand, it
captures the dominant orientations in a local spatial region taking into
account of the local shape of the edges structure. In fact, it is based on the
structure tensor that represents a very interesting concept for characterizing
the local shape. On the other hand, the use of the histogram concept makes the
proposed descriptor so effective and useful when a reduced feature
representation is required. In this paper, the proposed HoST descriptor is addressed
to the pattern clustering task. An extensive experimental validation
demonstrates its performance when compared to other existing feature
descriptors such as Local Binary Patterns and Histogram of Oriented Gradients.
In addition, the proposed descriptor succeeds in improving the performance of
clustering based resolution enhancement approaches.
Lange,P., Weller,R., Zachmann,G.
Abstract:
A central part of virtual reality systems and game engines is the generation,
management and distribution of all relevant world states. In modern interactive
graphic software systems usually many independent software components need to
communicate and exchange data. Standard approaches suffer the $n^2$ problem
because the number of interfaces grows quadratically with the number of
component functionalities. Such many-to-many architectures quickly become
unmaintainable, not to mention latencies of standard concurrency control
mechanisms. We present a novel method to manage concurrent multithreaded access
to shared data in virtual environments. Our highly efficient low-latency and
lightweight architecture is based on a new wait-free hash map using key-value pairs.
This allows us to reduce the traditional many-to-many problem to a simple
many-to-1 approach. Our results show that our framework outperforms by an order
of magnitude standard lock-based but also modern lock-free methods
significantly.
Ulrich,Ch., Grund,N., Derzapf,E., Lobachev,O., Guthe,M.
Abstract:
When extracting iso-surfaces from large volume data sets, long processing times
are required and a high number of polygons is generated. We propose a massively
parallel iso-surface extraction and simplification algorithm. The extraction is
based on the marching cubes algorithm. In order to process large volume data
sets, we perform the extraction with an interleaved simplification step using
parallel edge collapses and the quadric error metrics.
Interleaving extraction and simplification is based on locally postponing
collapse operations close to the processing front. In contrast to previous
methods, we do not need an explicit simplification error fall-off close to the
front. Thus we can produce meshes with the same quality as if we would simplify
the complete mesh after extraction. By implementing both extraction and
simplification on the GPU, we can reconstruct high quality iso-surfaces from
large data sets within a few seconds.
Jeon,S.-H., Chung,Y.-K., Yoon,H.-S
Abstract:
In this paper, we propose an algorithm estimating the vanishing point(VP) of a
sidewalk in a man-made environment from a single image. For finding the VP, the
lines in an image are efficiently exploited as a clue because the projections
of parallel lines in an image intersect at a VP. However, there are too many
noises disturbing line detection in natural scene images, for example trees,
pedestrian and shadows. Thus, we suggest a noise reduction technique called
orientation consistency pass filtering(OCPF) for improving line detection
performance. An edge orientation at the window center of OCPF is compared to
its neighbor edge orientations for calculating orientation difference. The
center pixel is removed if the difference of edge orientations greater than a
threshold, and preserved otherwise. In addition, we suggest a novel vanishing
point detection method using edge orientation voting(EOV), which predict VP
position accurately. The lines filtered by OCPF can generate the VP candidates
using bottom-up extended lines. The VP candidates receive supports from all
edges below the currently inspected VP candidate. The most supported VP
candidate is selected as dominant VP. This proposed method was implemented and
tested on 600 sidewalk image database that has 640x320 resolutions. 81% of the
test sidewalk images are in range from 0 pixels to 30 pixels from manually
marked VP.
Zhang,F., Tourre,V., Moreau,G.
Abstract:
Information visualization is widely involved in our daily life. It develops
rapidly in both 2D and 3D environments. In the 3D case, evaluation is a
critical problem. Existent evaluation metrics are firstly introduced in this
paper. We chose to focus on mathematical metrics only and several metrics
referring existent ones are designed to evaluate a text-based information
visualization in 3D urban environment. Afterwards, some modifications of the
visualization are gained by constructing processing functions which take into
account the object space distance and the screen space distance. A
re-evaluation process for the new results is conducted to see if the
visualization result is improved or not. Results show that screen space
functions have better performance in improving visualization performance, which
can provide references for visualization designers to diversify and
characterize their visualizations.
Tian,L.
Abstract:
For the application of ocean wave, a new height-field simulation method is
proposed by the mix of FFT and Perlin Noise, and OpenSceneGraph (OSG) and VC++
2008 are used to simulate realistic ocean wave. The method takes wind effects
into consideration, and uses Philips model and Gauss random numbers to produce
ocean wave spectrum, which is then transformed to wave height-field by FFT.
Perlin Noise is overlaid to disturb the wave height to generate a vivid and
random sea surface. Simulation results show the effectiveness of the proposed
method.
Antemijczuk,P., Magiera,M., Lehmann,S., Cuttone,A., Larsen,J.
Abstract:
In this paper, we propose a visualization to illustrate social interactions,
built from multiple distinct channels of communication. The visualization
displays a summary of dense personal information in a compact graphical
notation. The starting point is an abstract drawing of a spider‘s web. Below,
we describe the meaning of each data dimension along with the background and
motivation for their inclusion. Finally, we present feedback provided by the
users (31 individuals) of the visualization.
Benziane,S., Merouane,A.
Abstract:
This paper presents a new approach to authenticate individuals using hand vein
images. The proposed method is fully automated and employs palm dorsal hand
vein images acquired from a low cost, near infrared contactless imaging; the
aim of our work. In order to evaluate the system performance, a prototype was
designed and a dataset of 34 persons from different ages above 20 and different
gender, in each step 10 images per person was acquired at different intervals,
5 images for left hand and 5 images for right hand. The vein detection process
consists of an easy to implement a device that takes a snapshot of the subject‘s
veins under a source of infrared radiation at a specific wavelength. The system
is able to detect veins but not arteries due to the specific absorption of
infrared radiation in blood vessels. Almost any part of the body could be
analyzed in order to extract an image of the vascular pattern but the hand and
the fingers are preferred.
Bezuglov,D.A., Bezuglov,Yu.D., Shvidchenko,S.A.
Abstract:
Currently known algorithms suppose preliminary image filtering with consecutive
solving of edges extraction problem. In the process of development of image
filtering algorithms the a priori knowledge of distortion interference
characteristics is also required. In practice in most of the cases such
information is not available or is approximate. A new method of objects‘ edges
extraction in the images was developed, in the presence of distortion, by
applying direct and inverse wavelet transformation. The results of mathematical
modeling are provided. The proposed approach may be used in the course of
development of digital picture processing systems, self-contained robots
engineering, and under the surveillance conditions which complicate the
registration process in the absence of a priori data about the background noise
type.
Gdawiec,K., Kotarski,W., Lisowska,A.
Abstract:
In the paper visualizations of some modifications based on the Newton's root
finding of complex polynomials are presented. Instead of the standard Picard
iteration several different iterative processes described in the literature,
that we call as non-standard ones, are used. Following Kalantari such
visualizations are called polynomiographs. Polynomiographs are interesting from
scientific, educational and artistic points of view. By the usage of different
kinds of iterations we obtain quite new, comparing to the standard Picard
iteration, polynomiographs that look aesthetically pleasing. As examples we
present some polynomiographs for complex polynomial equation z^3 - 1 = 0.
Polynomiographs graphically present dynamical behaviour of different iterative
processes. But we are not interested in it. We are focused on polynomiographs
from the artistic point of view. We believe that the new polynomiographs can be
interesting as a source of aesthetic patterns created automatically. They also
can be used to increase functionality of the existing polynomiography software.
Lahdenoja,O., Säntti,T., Laiho,M., Poikonen,J.
Abstract:
This paper presents methods for automated visual tracking of spatters in laser-
and manual arc welding. Imaging of the welding process is challenging due to
extreme conditions of high radiated light intensity variation. The formation
and the number of spatters ejected in the welding process are dependent on the
parameters of the welding process, and can potentially be used to tune the
process towards better quality (either on-line of off-line). In our case, the
spatter segmentation is based either on test on object elongatedness or Hough
transform, which are applied on pre-processed image sequences captured by a
high-speed smart camera. Part of the segmentation process (adaptive image
capture and edge extraction) is performed on the camera, while the other parts
of the algorithm are performed off-line in Matlab. However, our intention is to
move the computation towards the camera or an attached FPGA.
Milet,T., Kobrtek,J., Zemčík,P., Pečiva,J.
Abstract:
This paper presents a new simple, fast and robust approach in computation of
per-sample precise shadows. The method uses tessellation shaders for
computation of silhouettes on arbitrary triangle soup. We were able to reach
robustness by our previously published algorithm using deterministic shadow
volume computation. We also propose a new simplification of the silhouette
computation by introducing reference edge testing. Our new method was compared
with other methods and evaluated on multiple hardware platforms and different
scenes, providing better performance than current state-of-the art algorithms.
Finally, conclusions are drawn and the future work is outlined.
Akagi,Y., Kawasaki,H.
Abstract:
In this paper, we propose a method for recognizing a micro expression which is
a small motion appearing on a face by using the high density and high
frame-rate 3D reconstruction method. Some studies report that the micro expressions
are caused by the change of mental state. If we can recognize the micro
expressions, this information could be useful for machines to understand the
mental state of a human. With advancements of 3D reconstruction methods,
methods have been proposed to reconstruct dynamic objects such as motions of a
human's body in high accuracy with high frame rate. Based on the data obtained
from the high quality shape reconstruction method, the proposed method
recognizes the micro expressions. To detect a part of the face where the
micro-expressions are appeared, we propose an experimental estimation of the
part. We also report a recognition rate of the change of the mental state using
the experimental system.
Endler,M., Lobachev,O., Guthe,M.
Abstract:
We present a detector cascade for robust real-time tracking of hand movements
on consumer-level hardware. We adapt existing detectors to our setting: Haar,
CAMSHIFT, shape detector, skin detector. We use all these detectors at once.
Our main contributions are: first, utilization of bootstrapping: Haar
bootstraps itself, then its results are used to bootstrap the other filters;
second, the usage of temporal filtering for more robust detection and to remove
outliers; third, we adapted the detectors for more robust hand detection. The
resulting system produces very robust results in real time. We evaluate both
the robustness and the real-time capability.
Warszawski,K.K., Nikiel,S.S.
Abstract:
This paper proposes a method that applies particle systems to simulate results
of hydrological erosion caused by spout, like riverbeds. The terrain model is
divided into two layers. The first one stores heights data (typical
height-field) while the second is reserved for hardness data. This data
structure enables fast and simple implementation of terrain deformation. We
present the construction of a particle system terrain modifier, its main
attributes and how they influence the final product of the modelling process.
The proposed technique behaves like in classical particle systems. It uses
emitter as element that control starting location, direction and quantity of
particles in a given simulation environment. We choose parameters for particles
such as: the current position, directional angle, linear velocity, rotation
angle, rotation velocity and the size which define its zone of influence for
landscape modification processes. Each emitted particle is moving (rolling)
over the surface of terrain structure making deformations at its current
position. Scale of the modifications depends on particle parameters and
landscape structure susceptibility for modifications process under the particle
influence zone. The proposed method is not intended to simulate physically
erosion process, but focuses on its results for exploitation in virtual
environments in real-time simulations and rapid prototyping of virtual
terrains.
Dundas,J., Wagner,M.
Abstract:
Interactive digital public displays that track viewer's position are currently
inaccessible to the average consumer. Many tracking systems available on the
market are prohibitively expensive and are out of scope for small business
owners to purchase. This research tests various consumer level tracking
technologies to ascertain whether a system can be developed in a low cost and
accessible manner. Microsoft's Kinect in tandem with Unity3D offers a system
that is straightforward to use and allows for ease of implementation. The
resulting technique can be quickly carried out to create an interactive digital
public display.
Giang,K., Funk,M.
Abstract:
In our current society, open data streams are more and more available through
the Internet. This data can have an increasing impact on everyday life. Its
full potential can, however, only reached through better integration and new
interfaces. The goal of this project is to explore the possibilities of
repurposing public information in an developing area of a large city in the
Netherlands. Can we create a tangible interaction with use of physical visualization
of these data streams? A series of prototypes have been made to develop a
physical visualization through the method of research through design. Users
were involved in expert panels and interviews to fine-tune and create a final
prototype, Connect-S. The concept shows the opportunities of using physical
visualization in connection with physical interaction for browsing and
navigation.
Zyuzin,V., Porshnev,S., Bobkova,A.
Abstract:
The article presents the study result of signature of left ventricle (LV)
contours which are built by experts.The result is a part of a task of automatic
contouring area of LV on an ultrasound frames with apical four-chamber view.
Signature is LV contour curve, built in polar coordinates. The study was found
the optimal point in the center of the LV base. The resulting signature is
approximated by three polynomials second and third degree: right side, left
side and top. The result of such approximation has been qualitatively and
quantitatively better than the whole curve.
Kovačić,K., Ivanjko,E., Gold,H.
Abstract:
Development of computing power and cheap video cameras enabled today's traffic
management systems to include more cameras and computer vision applications for
transportation system monitoring and control. Combined with image processing
algorithms cameras are used as sensors to measure road traffic parameters like
flow, origin-destination matrices, classify vehicles, etc. In this paper
development of a system capable to measure traffic flow and estimate vehicle
trajectories on multiple lanes using one static camera is described. Vehicles
are detected as moving objects using foreground and background image
segmentation. Adjacent pixels in the moving objects image are grouped together
and a weight factor based on cluster area, cluster overlapping area and distance
between multiple clusters is computed to enable multiple moving object
tracking. To ensure real-time capabilities, image processing algorithm
parallelization is applied. Described system is tested using real traffic video
footage obtained from Croatian highways.
Nowinski,K.S., Borucki,B.
Abstract:
A new, dataflow driven, modular visual data analysis platform with extensive
data processing and visualization capabilities is presented. VisNow is written
in Java, easily extendable to incorporate new modules and module libraries.
Dataflow networks built with the help of interactive network editor can be
wrapped into stand-alone application for the end users
Simons,A., Prakash,E., Wood,J.
Abstract:
These are Preliminary Results: Generating images on computer systems has been
done with the same technology for several decades now. Bitmap or pixel
technology is used for the representation of rich color images. Simple graphics
like line drawings and logos usually use vector graphics. As known both have
their disadvantages and advantages. In recent years a lot of research has been
done to combine the advantages of both techniques in a comprehensive solution.
However all these research started from one of these two technologies as base,
so new technologies were built on top of existing technologies. There was no
development from scratch and that's exactly what this paper wants to propose,
an algorithm to invent the pixel again. By always applying new developments on
existing technologies generating images became a mix of various techniques and
a rather complex matter. A latest contribution to this, for instance, is the
use of Diffusion Curves. As said before, all research has been fixed on
improving existing pixel or vector based graphics. With the use of VectorPixel
(VP) the concept of a pixel will be redefined. In contrast with a pixel
(Picture Element) a VectorPixel will be defined by a mathematically description
and resolution independent. Instead of using a classical grid, which is
resolution depended, to position a VectorPixel a reference point will be
defined and the position of other VectorPixels will refer to that reference
point. Classical pixels make use of a grid which is resolution depended.
VectorPixels instead can for example overlap each other to present a smooth
curve. When the image is enlarged VectorPixels are also increased
proportionately.
Jang,H.J., Baek,S.-H., Park,S.-Y.
Abstract:
Robustly extracting the features of lane markings under different lighting and
weather conditions such as shadows, glows, sunset and night is the a key
technology of the lane departure warning system (LDWS). In this paper, we
propose a robust lane marking feature extraction method. By useing the
characteristics of the lane marking to detect candidate areas. The final lane
marking features are extracted by first finding the center points of the lane
marking in the candidate area then these center point pixels are labeled
according to the intensity similarity along the direction of the vanishing
point. The performance of the proposed method is evaluated by experiment at
results using real world lane data.
Kim,J.-W., Kang,K.-K., Lee,J.-H.
Abstract:
LEGO has been very popular toy in the world because it is attractive and fun to
play with and stimulates one's creativity by providing means to conveniently
assemble a variety of interesting shapes using the limited types of given
bricks. However, it is hard for the beginners to design and assemble complex
models they desire to make without instructions. Building a LEGO assembly
manually usually requires a significant amount of trial-and-error. LEGO company
therefore presented the LEGO construction problem in 1998 and in 2001. The
problem statement is "Given any 3D body, how can it be built from LEGO
bricks?" In this paper we will investigate the current research efforts to
address the LEGO construction problem. We will review the problem definition,
formulation, and a variety of approaches to solve the problem. We will discuss
the data representations for input 3D polygonal models and the LEGO assembly
structures, cost functions that will guide the search for the optimal solution,
and various solution methods.
Bukatov,A.A., Gridchina,E.E., Zastavnoy,D.A.
Abstract:
Modeling plausible deformation of the objects has been an important task in
computer animation and game design industry. The approach proposed in the paper
deals with polygonal mesh deformation splitting the vertices of the mesh into
two types: cluster vertices and free vertices. With the user defining the shape
of the mesh key areas with the help of cluster vertices, the algorithm takes
advantage of non-linear geometric deformation for calculating free vertices
position. The approach could be used both for creating a sequence of altered
model shapes to produce a character animation (with the help of user-created
control cluster data) and for visualizing some ecological processes.
City Tour
Thursday June 5, 2014
The afternoon City tour schedule is
expected as follows [read the NOTE at the registration desk
– MIGHT CHANGE]:
14:30 - Start at the Slovan hotel, State Technical Library,
the Municipal Gardens - Smetana sady [Smetana'sPark]
14:45 - Great Theatre, Great Synagogue
15:00 - Stara sladovna - a medival pub [Old Malt-House], beer tasting
15:30 - the longest bridge in the world :-)
15:45 - Brewery Museum [http://www.prazdrojvisit.cz/cz/pivovarske-muzeum/],
Parkan Pub, The Watter Tower, Prague's bridge
16:00 - Gallery "Mastne kramy" [Butcher's market], the Municipal Gardens
- Kopeckeho sady [Kopecky's park]
16:30 - Museum of West Bohemia, Mestanska beseda [Municipal Meeting
House], Franciscan Monastery and Church of the Assumption
17:00 - The Republic Square, Good luck cherub – the place, where your
wishes will become true
17:30 - Town Hall and the Plzen city model, Imperial House, Plague column
17:45 - St.Bartholomew's Cathedral, Cathedral Tower
18:00 – TOUR END (the St.Bartholomew's Cathedral should be open for a
service and open for public as well)
You can join me and have a dinner and beer(s), beer(s).......... at the most
world famous Plzen brewery - Prazdroj - Pilsner Urquell
18:30 - Brewery - Spilka Restaurant [http://www.naspilce.com/en]
Dinner (approx. 8 EUR) and beer 0.5L (approx.1.5 EUR)
WSCG 2014 Conference Schedule
Registration Monday, June 2 17:30 - 20:30 Conference office is open during breaks, only
Tuesday, June 3, 2014
|
8:30 - 10:00 |
30' |
10:30 - 12:00 |
20' |
12:20 |
13:30 - 14:30 |
60' |
15:30 - 17:30 |
16:30 -17:30 |
|||||||
|
Session A1 |
Break |
Session B1 |
Welcome |
Lunch |
C1 |
Break & |
Session D1 |
Late |
|||||||
|
Room A |
Room A |
Room A |
|||||||||||||
|
Session A2 |
Session B2 |
Session D2 |
|||||||||||||
|
Room B |
Room B |
Room B |
|||||||||||||
|
Wednesday, June 4, 2014 |
|||||||||||||||
|
8:30 -10:00 |
30' |
10:30 -12:00 |
20' |
12:20 |
13:30 -14:30 |
60' |
15:30 -17:30 |
|
18:59* |
||||||
|
Session F1 |
Break & |
Session G1 |
Common |
Lunch |
H1 |
Break & |
Session K1 |
FREE |
DINNER |
||||||
|
Room A |
Room A |
Room A |
|||||||||||||
|
Session F2 |
Session G2 |
Session K2 |
|||||||||||||
|
Room B |
Room B |
Room B |
|||||||||||||
|
Thursday, June 5, 2014 |
|||||||||||||||
|
8:30 - 9:30 |
30' |
10:00 - 11:30 |
30' |
10' |
14:30 -???? |
||||||||||
|
Session L1 |
Break |
Session M1 |
N1 |
Closing Session |
FREE |
Plzen City Sightseeing Tour
** |
|||||||||
|
Room A |
Room A |
||||||||||||||
|
Session L2 |
Session M2 |
||||||||||||||
|
Room B |
Room B |
||||||||||||||
* Expected ** NOT ORGANIZED – JOIN US AND PASS THE CITY CENTER
Conference Dinner: Wednesday, June 4 –
buy a ticket [at a symbolic price 10 EUR] at the registration – offer
limited.
Place and time to be announced. We recommend to
buy 24 hour/1 day ticket for public transport
We recommend visiting (not organized tours):
|
· Explore Plzen City http://web.zcu.cz/plzen/ |
· Techmania Science Center http://www.techmania.cz |
|
·
ZOO and Botanical Garden |
·
Stara Sladovna – Medieval Pub – city center (40 mins.) |
|
·
Purkmister Brewery |
·
Pilsner Urquell Brewery and Brewery Museum - |
`