2020-10-30T11:30:32Zhttp://edoc.mpg.de/ac_ft_oai.ploai:edoc.mpg.de:2017952012-09-1987:934
A Framework for Dynamic Connectivity Meshes
Vorsatz, Jens
Seidel, Hans-Peter
Reiners, D.
Implementing algorithms that are based on dynamic triangle meshes
often requires updating internal data-structures as soon as the
connectivity of the mesh changes. The design of a class hierarchy
that is able to deal with such changes is particularly challenging if the
system reaches a certain complexity.
The paper proposes a software design that enables the users to
efficiently implement algorithms that can handle these dynamic
changes while still maintaining a certain encapsulation of the
single components.
Our design is based on a callback mechanism. A client can register at some {\tt
Info}-object and gets informed whenever a change of the connectivity occurs.
This way the client is able to keep internal data up-to-date. Our framework
enables us to write small client classes that cover just a small dedicated
aspect of necessary updates related to the changing connectivity. These small
components can be combined to more complex modules and can often easily be
reused. Moreover, we do not have to store related 'dynamic data' in one central
place, e.g. the mesh, which could lead to a significant memory overhead if an
application uses some modules just for a short time.
We have used and tested this class design extensively for
implementing 'Dynamic Connectivity Meshes and
Applications~\cite{Vorsatz:2003:DRA}'. Additionally, as a
feasibility study, we have implemented and integrated our concept in the
\OM-framework.
ACM
2003
Conference-Paper
http://edoc.mpg.de/201795
OpenSG Symposium 2003, ACM, 49-55 (2003)
en
oai:edoc.mpg.de:2018392012-09-1987:934
Visualization of Volume Data with Quadratic Super Splines
Rössl, Christian
Zeilfelder, Frank
Nürnberger, Günther
Seidel, Hans-Peter
Turk, Greg
van Wijk, Jarke
Moorhead, Robert
We develop a new approach to reconstruct non-discrete models from
gridded volume samples. As a model, we use quadratic trivariate super
splines on a uniform tetrahedral partition . The approximating splines
are determined in a natural and completely symmetric way by averaging
local data samples, such that appropriate smoothness conditions are
automatically satisfied. On each tetrahedron of , the
quasi-interpolating spline is a polynomial of total degree two which
provides several advantages including efficient computation,
evaluation and visualization of the model. We apply Bernstein-B´ezier
techniques well-known in CAGD to compute and evaluate the trivariate
spline and its gradient. With this approach the volume data can be
visualized efficiently e.g. with isosurface raycasting. Along an
arbitrary ray the splines are univariate, piecewise quadratics and
thus the exact intersection for a prescribed isovalue can be easily
determined in an analytic and exact way. Our results confirm the
efficiency of the quasi-interpolating method and demonstrate high
visual quality for rendered isosurfaces.
IEEE
2003
Conference-Paper
http://edoc.mpg.de/201839
IEEE Visualization 2003 (VIS-03), IEEE, 393-400 (2003)
en
oai:edoc.mpg.de:2018432012-09-1987:934
Dynamic Remeshing and Applications
Vorsatz, Jens
Rössl, Christian
Seidel, Hans-Peter
Elber, Gershon
Shapiro, Vadim
Triangle meshes are a flexible and generally accepted boundary
representation for complex geometric shapes. In addition to their
geometric qualities and topological simplicity, \emph{intrinsic}
qualities such as the shape of the triangles, their distribution on
the surface and the connectivity are essential for many algorithms
working on them. In this paper we present a flexible and efficient
remeshing framework that improves these intrinsic properties while
keeping the mesh geometrically close to the original surface. We
use a particle system approach and combine it with an incremental
connectivity optimization process to trim the mesh towards the
requirements imposed by the user. The particle system uniformly
distributes the vertices on the mesh, whereas the connectivity
optimization is done by means of \emph{Dynamic Connectivity Meshes},
a combination of local topological operators that lead to a fairly
regular connectivity. A dynamic skeleton ensures that our approach
is able to preserve surface features, which are particularly
important for the visual quality of the mesh. None of the
algorithms requires a global parameterization or patch layouting in
a preprocessing step but uses local parameterizations only. We also
show how this general framework can be put into practice and sketch
several application scenarios. In particular we will show how the
users can adapt the involved algorithms in a way that the resulting
remesh meets their personal requirements.
ACM
2003
Conference-Paper
http://edoc.mpg.de/201843
Proceedings: 8th ACM Symposium on Solid Modeling and Applications (SM-03), ACM, 167-175 (2003)
en
oai:edoc.mpg.de:2018722012-09-1987:934
Accuracy of 3D Range Scanners by Measurement of the Slanted Edge Modulation Transfer Function
Goesele, Michael
Fuchs, Christian
Seidel, Hans-Peter
Rioux, Marc
Godin, Guy
Boulanger, Pierre
We estimate the accuracy of a 3D~range scanner in terms of its
spatial frequency response. We determine a scanner's modulation
transfer function (MTF) in order to measure its frequency response.
A slanted edge is scanned from which we derive a superresolution
edge profile. Its Fourier transform is compared to the Fourier
transform of an ideal edge in order to determine the MTF of the
device. This allows us to determine how well small details can be
acquired by the 3D~scanner. We report the results of several
measurements with two scanners under various conditions.
IEEE
2003
Conference-Paper
http://edoc.mpg.de/201872
4th International Conference on 3-D Digital Imaging and Modeling, IEEE, 37-44 (2003)
en
oai:edoc.mpg.de:2019492012-09-1987:934
Using Feature Flow Fields for Topological Comparison of Vector Fields
Theisel, Holger
Rössl, Christian
Seidel, Hans-Peter
Ertl, Thomas
Girod, Bernd
Greiner, Günther
Niemann, Heinrich
Seidel, Hans-Peter
Steinbach, Eckehard
Westermann, Rüdiger
In this paper we propose a new topology based metric for 2D vector
fields. This metric is based on the concept of feature flow
fields. We show that it incorporates both the characteristics and
the local distribution of the critical points while keeping the
computing time reasonably small even for topologically complex
vector fields. Finally, we apply the metric to track the
topological behavior in a time-dependent vector field, and to
evaluate a smoothing procedure on a noisy steady vector field.
Akademische Verlagsgesellschaft Aka
2003
Conference-Paper
http://edoc.mpg.de/201949
urn:ISBN:3-89838-048-3
Vision, Modeling and Visualization 2003 (VMV-03) : proceedings, Akademische Verlagsgesellschaft Aka, 521-528 (2003)
en
oai:edoc.mpg.de:2019522012-09-1987:934
Tree-based Triangle Mesh Connectivity Encoding
Rössl, Christian
Ivrissimtzis, Ioannis
Seidel, Hans-Peter
Cohen, Albert
Merrien, Jean-Louis
Schumaker, Larry L.
We present a divide and conquer algorithm for triangle mesh
connectivity encoding. As the algorithm traverses the mesh it
constructs a weighted binary tree that holds all information required for
reconstruction. This representation can be used for compression.We derive a new
iterative single-pass decoding algorithm, and we show how to exploit the tree
data structure
for generating stripifications for efficient rendering that come with a
guaranteed cost saving.
Nashboro Press
2003
Conference-Paper
http://edoc.mpg.de/201952
urn:ISBN:0-9728482-1-5
Curve and Surface Fitting: Saint-Malo 2002, Nashboro Press, 345-354 (2003)
en
oai:edoc.mpg.de:2019702012-09-1987:934
Image-Based Reconstruction of Spatial Appearance and Geometric Detail
Lensch, Hendrik P. A.
Kautz, Jan
Goesele, Michael
Heidrich, Wolfgang
Seidel, Hans-Peter
Real-world objects are usually composed of a number of different materials that
often show subtle changes even within a single material. Photorealistic
rendering of such objects requires accurate measurements of the reflection
properties of each material, as well as the spatially varying effects. We
present an image-based measuring method that robustly detects the different
materials of real objects and fits an average bidirectional reflectance
distribution function (BRDF) to each of them. In order to model local changes
as well, we project the measured data for each surface point into a basis
formed by the recovered BRDFs leading to a truly spatially varying BRDF
representation. Real-world objects often also have fine geometric detail that
is not represented in an acquired mesh. To increase the detail, we derive
normal maps even for non-Lambertian surfaces using our measured BRDFs. A high
quality model of a real object can be generated with relatively little input
data. The generated model allows for rendering under arbitrary viewing and
lighting conditions and realistically reproduces the appearance of the original
object.
Permission to make digital or hard copies of part or all of this work for
personal or classroom use is granted without fee provided that copies are not
made or distributed for profit or commercial advantage and that copies bear
this notice and the full citation on the first page. Copyrights for components
of this work owned by others than ACM must be honored. Abstracting with credit
is permitted. To copy otherwise, to republish, to post on servers or to
redistribute to lists, requires prior specific permission and/or a fee.
2003
Article
http://edoc.mpg.de/201970
ACM Transactions on Graphics, v.22, 234-257 (2003)
en
oai:edoc.mpg.de:2019732012-09-1987:934
Combining Topological Simplification and Topology Preserving Compression for 2D Vector Fields
Theisel, Holger
Rössl, Christian
Seidel, Hans-Peter
Rokne, Jon
Klein, Reinhard
Wang, Wenping
Topological simplification techniques and topology preserving
compression approaches for 2D vector fields have
been developed quite independently of each other. In this
paper we propose a combination of both approaches: a vector
field should be compressed in such a way that its important
topological features (both critical points and separatrices)
are preserved while its unimportant features are allowed
to collapse and disappear. To do so, a number of new
solutions and modifications of pre-existing algorithms are
presented. We apply the approach to a flow data set which,
is both large and topologically complex, and achieve significant
compression ratios there.
IEEE
2003
Conference-Paper
http://edoc.mpg.de/201973
11th Pacific Conference on Computer Graphics and Applications (PG-03), IEEE, 419-423 (2003)
en
oai:edoc.mpg.de:2019752012-09-1987:934
Accurate Light Source Acquisition and Rendering
Goesele, Michael
Granier, Xavier
Heidrich, Wolfgang
Seidel, Hans-Peter
Hodgins, Jessica K.
Realistic image synthesis requires both complex and realistic models
of real-world light sources and efficient rendering algorithms to deal
with them. In this paper, we describe a processing pipeline for
dealing with complex light sources from acquisition to global
illumination rendering. We carefully design optical filters to
guarantee high precision measurements of real-world light sources. We
discuss two practically feasible setups that allow us to measure light
sources with different characteristics.
Finally, we introduce an efficient importance sampling
algorithm for our representation that can be used, for example, in
conjunction with Photon Maps.
ACM
2003
Conference-Paper
http://edoc.mpg.de/201975
Proceedings of ACM SIGGRAPH 2003 (SIGGRAPH-03), ACM, 621-630 (2003)
en
oai:edoc.mpg.de:2019792012-09-1987:934
Interactive Visualization of Complex Real-World Light Sources
Granier, Xavier
Goesele, Michael
Heidrich, Wolfgang
Seidel, Hans-Peter
Rokne, Jon
Klein, Reinhard
Wang, Wenping
Interactive visualization of complex, real-world light
sources has so far not been feasible. In this paper, we
present an hardware accelerated direct lighting algorithm
based on a recent high quality light source acquisition technique.
By introducing an approximate reconstruction of the
exact model, a multi-pass rendering approach, and a compact
data representation, we are able to achieve interactive
frame rates. The method is part of the processing pipeline
from light source acquisition to high quality lighting of a
virtual world.
IEEE
2003
Conference-Paper
http://edoc.mpg.de/201979
11th Pacific Conference on Computer Graphics and Applications (PG-03), IEEE, 59-66 (2003)
en
oai:edoc.mpg.de:2019852012-09-1987:934
Virtualizing Real-World Objects
Lensch, Hendrik P. A.
Kautz, Jan
Goesele, Michael
Lang, Jochen
Seidel, Hans-Peter
IEEE Computer Society
2003
Conference-Paper
http://edoc.mpg.de/201985
Computer Graphics International (CGI 2003), IEEE Computer Society, 134-141 (2003)
en
oai:edoc.mpg.de:2020462012-09-1987:934
Compression of 2D vector fields under guaranteed topology preservation
Theisel, Holger
Rössl, Christian
Seidel, Hans-Peter
Brunet, Pere
Fellner, Dieter W.
In this paper we introduce a new compression technique for 2D vector fields
which preserves the complete topology, i.e., the critical points and the
connectivity of the separatrices. As the theoretical foundation of the
algorithm, we show in a theorem that for local modifications of a vector field,
it is possible to decide entirely by a local analysis whether or not the global
topology is preserved. This result is applied in a compression algorithm which
is based on a repeated local modification of the vector field - namely a
repeated edge collapse of the underlying piecewise linear domain. We apply the
compression technique to a number of data sets with a complex topology and
obtain significantly improved compression ratios in comparison to pre-existing
topology-preserving techniques.
Blackwell
2003
Conference-Paper
http://edoc.mpg.de/202046
EUROGRAPHICS 2003 (EUROGRAPHICS-03) : the European Association for Computer Graphics, 24th Annual Conference, Blackwell, 333-342 (2003)
en
oai:edoc.mpg.de:2313092012-09-1987:934
Interactive {Ray} {Tracing} of {Free-Form} {Surfaces}
Benthin, Carsten
Wald, Ingo
Slusallek, Philipp
van Zijl, Lynette
Marais, Patrick
Even though the speed of software ray tracing has recently been
increased to interactive performance even on standard PCs, these
systems usually only supported triangles as geometric primitives.
Directly handling free-form surfaces such as spline or subdivision
surfaces instead of first tessellating them offers many advantages
such as higher precision results, reduced memory requirements, and
faster preprocessing due to less primitives. However, existing
algorithms for ray tracing free-form surfaces are much too slow for
interactive use.
In this paper we present a simple and generic approach for ray
tracing free-form surfaces together with specific implementations
for cubic B\'ezier and Loop subdivision surfaces. We show that our
approach allows to increase the performance by more than an order of
magnitude, requires only constant memory, and is largely independent
on the total number of free-form primitives in a scene. Examples
demonstrate that even scene with over one hundred thousand free-form
surfaces can be rendered interactively on a single processor at
video resolution.
ACM
2004
Conference-Paper
http://edoc.mpg.de/231309
urn:ISBN:1-58113-863-6
Proceedings AFRIGRAPH 2004 : 3rd International Conference on Virtual Reality, Computer Graphics, Visualisation and Interaction in Africa, ACM, 99-106 (2004)
en
oai:edoc.mpg.de:2313212012-09-1987:934
DISCO - Acquisition of Translucent Objects
Goesele, Michael
Lensch, Hendrik P. A.
Lang, Jochen
Fuchs, Christian
Seidel, Hans-Peter
Marks, Joe
Translucent objects are characterized by diffuse light scattering
beneath the object's surface. Light enters and leaves an object at
possibly distinct surface locations. This paper presents the first
method to acquire this transport behavior for arbitrary
inhomogeneous objects. Individual surface points are illuminated in
our DISCO measurement facility and the object's impulse response is
recorded with a high-dynamic range video camera. The acquired data
is resampled into a hierarchical model of the object's light
scattering properties. Missing values are consistently interpolated
resulting in measurement-based, complete and accurate
representations of real translucent objects which can be rendered
with various algorithms.
2004
Article
http://edoc.mpg.de/231321
urn:ISSN:0730-0301
ACM Transactions on Graphics, v.23, 835-844 (2004)
en
oai:edoc.mpg.de:2313242012-09-1987:934
Realtime Caustics using Distributed Photon Mapping
Günther, Johannes
Wald, Ingo
Slusallek, Philipp
Keller, Alexander
Jensen, Henrik Wann
With the advancements in realtime ray tracing and new global illumination
algorithms we are now able to render the most important illumination effects at
interactive rates. One of the major remaining issues is the fast and efficient
simulation of caustic illumination, such as e.g. the illumination from a car
headlight. The photon mapping algorithm is a simple and robust approach that
generates high-quality results and is the preferred algorithm for computing
caustic illumination. However, photon mapping has a number of properties that
make it rather slow on today s processors. Photon mapping has also been
notoriously difficult to parallelize efficiently.
In this paper, we present a detailed analysis of the performance issues of
photon mapping together with signifi- cant performance improvements for all
aspects of the photon mapping technique. The solution forms a complete
framework for realtime photon mapping that efficiently combines realtime ray
tracing, optimized and improved photon mapping algorithms, and efficient
parallelization across commodity PCs. The presented system achieves realtime
photon mapping performance of up to 22 frames per second on non-trivial scenes,
while still allowing for interactively updating all aspects of the scene,
including lighting, material properties, and geometry.
Eurographics
2004
Conference-Paper
http://edoc.mpg.de/231324
urn:ISBN:3-905673-12-6
Rendering Techniques 2004 : Eurographics Symposium on Rendering, Eurographics, 111-121 (2004)
en
oai:edoc.mpg.de:2313382012-09-1987:934
Differential Coordinates for Interactive Mesh Editing
Lipman, Yaron
Sorkine, Olga
Cohen-Or, Daniel
Levin, David
Rössl, Christian
Seidel, Hans-Peter
Giannini, Franca
Pasko, Alexander
One of the main challenges in editing a mesh is to retain the visual appearance
of the surface after applying various modifications. In this paper we advocate
the use of linear differential coordinates as means to preserve the
high-frequency detail of the surface. The differential coordinates represent
the details and are defined by a linear transformation of the mesh vertices.
This allows the reconstruction of the edited surface by solving a linear system
that satisfies the reconstruction of the local details in least squares sense.
Since the differential coordinates are defined in a global coordinate system
they are not rotation-invariant. To compensate for that, we rotate them to
agree with the rotation of an approximated local frame. We show that the linear
least squares system can be solved fast enough to guarantee interactive
response time thanks to a precomputed factorization of the coefficient matrix.
We demonstrate that our approach enables to edit complex detailed meshes while
keeping the shape of the details in their natural orientation.
IEEE
2004
Conference-Paper
http://edoc.mpg.de/231338
urn:ISBN:0-7695-1909-1
Shape Modeling International 2004 (SMI 2004), IEEE, 181-190 (2004)
en
oai:edoc.mpg.de:2313402012-09-1987:934
A Hybrid Hardware-Accelerated Algorithm for High Quality Rendering of Visual Hulls
Li, Ming
Magnor, Marcus
Seidel, Hans-Peter
Heidrich, Wolfgang
Balakrishnan, Ravin
In this paper, a novel hybrid algorithm is presented for the fast construction
and high-quality rendering of visual hulls. We combine the strengths of two
complementary hardware-accelerated approaches: direct constructive solid
geometry (CSG) rendering and texture mapping-based visual cone trimming. The
former approach completely eliminates the aliasing artifacts inherent in the
latter, whereas the rapid speed of the latter approach compensates for the
performance deficiency of the former. Additionally, a new view-dependent
texture mapping method is proposed. This method makes efficient use of graphics
hardware to perform per-fragment blending weight computation, which yields
better rendering quality. Our rendering algorithm is integrated in a
distributed system that is capable of acquiring synchronized video streams and
rendering visual hulls in real time or at interactive frame rates from up to
eight reference views.
Canadian Information Processing Society
2004
Conference-Paper
http://edoc.mpg.de/231340
urn:ISBN:1-56881-227-2
Graphics Interface 2004, Canadian Information Processing Society, 41-48 (2004)
en
oai:edoc.mpg.de:2313422012-09-1987:934
Perception-motivated High Dynamic Range Video Encoding
Mantiuk, Rafal
Krawczyk, Grzegorz
Myszkowski, Karol
Seidel, Hans-Peter
Marks, Joe
Due to rapid technological progress in high dynamic range (HDR)
video capture and display, the efficient storage and
transmission of such data is crucial for the completeness of any HDR
imaging pipeline. We propose a new approach for
inter-frame encoding of HDR video, which is embedded in the
well-established MPEG-4 video compression standard. The key
component of our technique is luminance quantization
that is optimized for the contrast threshold perception in the
human visual system. The quantization
scheme requires only 10--11 bits to encode 12 orders of magnitude of
visible luminance range and does not lead to perceivable contouring
artifacts. Besides video encoding, the proposed quantization
provides perceptually-optimized luminance sampling for fast
implementation of any
global tone mapping operator using a lookup table.
To improve the quality of synthetic video sequences, we introduce
a coding scheme for discrete cosine transform (DCT) blocks with
high contrast. We demonstrate the capabilities of HDR video in
a player, which enables decoding, tone mapping, and applying
post-processing effects in real-time. The tone mapping algorithm as well
as its parameters can be changed interactively while the video is playing.
We can simulate post-processing
effects such as glare, night vision, and motion blur, which appear
very realistic due to the usage of HDR data.
2004
Article
http://edoc.mpg.de/231342
urn:ISSN:0730-0301
ACM Transactions on Graphics, v.23, 733-741 (2004)
en
oai:edoc.mpg.de:2313432012-09-1987:934
Visible Difference Predictor for High Dynamic Range Images
Mantiuk, Rafal
Myszkowski, Karol
Seidel, Hans-Peter
Thissen, Wil
Wieringa, Peter
Pantic, Maja
Ludema, Marcel
Since new imaging and rendering systems commonly use physically
accurate lighting information in the form of High-Dynamic Range
data, there is a need for an automatic visual quality assessment of the
resulting images. In this work we extend the Visual Difference Predictor (VDP)
developed by Daly to handle HDR data. This let us predict if a human observer
is able to perceive differences for a pair of HDR images under the adaptation
conditions corresponding to the real scene observation.
IEEE
2004
Conference-Paper
http://edoc.mpg.de/231343
urn:ISBN:0-7803-8567-5
2004 IEEE International Conference on Systems, Man & Cybernetics, IEEE, 2763-2769 (2004)
en
oai:edoc.mpg.de:2313442012-09-1987:934
Fast and {Accurate} {Ray-Voxel} {Intersection} {Techniques} for {Iso-Surface} {Ray} {Tracing}
Marmitt, Gerd
Kleer, Andreas
Friedrich, Heiko
Wald, Ingo
Slusallek, Philipp
Girod, Bernd
Magnor, Marcus
Seidel, Hans-Peter
Visualizing iso-surfaces of volumetric data sets is becoming
increasingly important for many practical applications. One crucial
task in iso-surface ray tracing is to find the correct intersection
of a ray with the trilinear-interpolated implicit surface defined by
the data values at the vertices of a given voxel. Currently
available solutions are either accurate but slow or they provide
fast but only approximate solutions.
In this paper, we analyze the available techniques and present a new
intersection algorithm. We compare and evaluate the new algorithm
against previous approaches using both synthetic test cases and real
world data sets.
The new algorithm is roughly three times faster but provides the
same image quality and better numerical stability as previous
accurate solutions.
Akademische Verlagsgesellschaft Aka
2004
Conference-Paper
http://edoc.mpg.de/231344
urn:ISBN:3-89838-058-0
Vision, modeling, and visualization 2004 (VMV-04), Akademische Verlagsgesellschaft Aka, 429-435 (2004)
en
oai:edoc.mpg.de:2313472012-09-1987:934
Reconstruction of Volume Data with Quadratic Super Splines
Rössl, Christian
Zeilfelder, Frank
Nürnberger, Günther
Seidel, Hans-Peter
We propose a new approach to reconstruct nondiscrete models from gridded volume
samples. As a model, we use quadratic trivariate super splines on a uniform
tetrahedral partition. We discuss the smoothness and approximation properties
of our model and compare to alternative piecewise polynomial constructions. We
observe as a non-standard phenomenon that the derivatives of our splines yield
optimal approximation order for smooth data, while the theoretical error of the
values is nearly optimal due to the averaging rules. Our approach enables
efficient reconstruction and visualization of the data. As the piecewise
polynomials are of the lowest possible total degree two, we can efficiently
determine exact ray intersections with an iso-surface for ray-casting.
Moreover, the optimal approximation properties of the derivatives allow to
simply sample the necessary gradients directly from the polynomial pieces of
the splines. Our results confirm the efficiency of the quasi-interpolating
method and demonstrate high visual quality for rendered isosurfaces.
2004
Article
http://edoc.mpg.de/231347
IEEE Transactions on Visualization and Computer Graphics, v.10, 397-409 (2004)
en
oai:edoc.mpg.de:2313482012-09-1987:934
Spline Approximation of General Volumetric Data
Rössl, Christian
Zeilfelder, Frank
Nürnberger, Günther
Seidel, Hans-Peter
Elber, Gershon
Patrikalakis, Nick
Brunet, Pere
We present an efficient algorithm for approximating huge general
volumetric data sets, i.e.~the data is given over arbitrarily shaped
volumes and consists of up to millions of samples. The method is based
on cubic trivariate splines, i.e.~piecewise polynomials of total
degree three defined w.r.t. uniform type-6 tetrahedral partitions of
the volumetric domain. Similar as in the recent bivariate
approximation approaches, the splines in three variables
are automatically determined from the discrete data as a result of a
two-step method, where local discrete least
squares polynomial approximations of varying degrees are extended by
using natural conditions, i.e.the continuity and smoothness properties
which determine the underlying spline space. The main advantages of
this approach with linear algorithmic complexity are as follows: no
tetrahedral partition of the volume data is needed, only small
linear systems have to be solved, the local variation and
distribution of the data is automatically adapted,
Bernstein-B{\'e}zier techniques well-known in Computer Aided
Geometric Design (CAGD) can be fully exploited, noisy data are
automatically smoothed. Our numerical examples with huge data sets
for synthetic data as well as some real-world data confirm the
efficiency of the methods, show the high quality of the spline
approximation, and illustrate that the rendered iso-surfaces inherit
a visual smooth appearance from the volume approximating splines.
Eurographics
2004
Conference-Paper
http://edoc.mpg.de/231348
urn:ISBN:3-905673-55-X
Proceedings of the 9th ACM Symposium on Solid Modeling and Applications (SM 2004), Eurographics, 71-82 (2004)
en
oai:edoc.mpg.de:2313502012-09-1987:934
Laplacian Surface Editing
Sorkine, Olga
Lipman, Yaron
Cohen-Or, Daniel
Alexa, Marc
Rössl, Christian
Seidel, Hans-Peter
Scopigno, Roberto
Zorin, Denis
Fellner, Dieter
Spencer, Stephen
Surface editing operations commonly require geometric details of the surface to
be preserved as much as possible. We argue that geometric detail is an
intrinsic property of a surface and that, consequently, surface editing is best
performed by operating over an intrinsic surface representation. We provide
such a representation of a surface, based on the Laplacian of the mesh, by
encoding each vertex relative to its neighborhood. The Laplacian of the mesh is
enhanced to be invariant to locally linearized rigid transformations and
scaling. Based on this Laplacian representation, we develop useful editing
operations: interactive free-form deformation in a region of interest based on
the transformation of a handle, transfer and mixing of geometric details
between two surfaces, and transplanting of a partial surface mesh onto another
surface. The main computation involved in all operations is the solution of a
sparse linear system, which can be done at interactive rates. We demonstrate
the effectiveness of our approach in several examples, showing that the editing
operations change the shape while respecting the structural geometric detail.
Eurographics
2004
Conference-Paper
http://edoc.mpg.de/231350
urn:ISBN:3-905673-13-4/1727-8384
SGP 2004 (SGP-04) : Symposium on Geometry Processing, Eurographics, 179-188,274 (2004)
en
oai:edoc.mpg.de:2313542012-09-1987:934
Topology Preserving Thinning of Vector Fields on Triangular Meshes
Theisel, Holger
Rössl, Christian
Seidel, Hans-Peter
Dodgson, Neil A.
Floater, Michael S.
Sabin, Malcom A.
We consider the topology of piecewise linear vector fields whose domain is a
piecewise linear 2-manifold, i.e. a triangular mesh. Such vector fields can
describe simulated 2-dimensional flows, or they may reflect geometric
properties of the underlying mesh. We introduce a thinning technique which
preserves the complete topology of the vector field, i.e. the critical points
and separatrices. As the theoretical foundation, we have shown in an earlier
paper that for local modiØcations of a vector field, it is possible to decide
entirely by a local analysis whether or not the global topology is preserved.
This result is applied in a number of compression algorithms which are based on
a repeated local modification of the vector field, namely a repeated
edge-collapse of the underlying piecewise linear domain.
Springer
2004
InBook
http://edoc.mpg.de/231354
urn:ISBN:3-540-21462-3
Advances in Multiresolution for Geometric Modelling, 353-366 (2004)
en
oai:edoc.mpg.de:2313552012-09-1987:934
Normal Based Estimation of the Curvature Tensor for Triangular Meshes
Theisel, Holger
Rössl, Christian
Zayer, Rhaleb
Seidel, Hans-Peter
Cohen-Or, Daniel
Ko, Hyeong-Seok
Terzopoulos, Demetri
Warren, Joe
We introduce a new technique for estimating the curvature tensor of a
triangular mesh. The input of the algorithm is only a single triangle equipped
with its (exact or estimated) vertex normals. This way we get a smooth function
of the curvature tensor inside each triangle of the mesh. We show that the
error of the new method is comparable with the error of a cubic fitting
approach if the incorporated normals are estimated. If the exact normals of the
underlying surface are available at the vertices, the error drops signifi-
cantly. We demonstrate the applicability of the new estimation at a rather
complex data set.
IEEE
2004
Conference-Paper
http://edoc.mpg.de/231355
urn:ISBN:0-7695-2234-3
12th Pacific Conference on Computer Graphics and Applications, PG 2004, IEEE, 288-297 (2004)
en
oai:edoc.mpg.de:2313642012-09-1987:934
An Interactive Out-of-Core Rendering Framework for Visualizing Massively Complex Models
Wald, Ingo
Dietrich, Andreas
Slusallek, Philipp
Keller, Alexander
Jensen, Henrik Wann
With the tremendous advances in both hardware capabilities and
rendering algorithms, rendering performance is steadily increasing.
Even consumer graphics hardware can render many million
triangles per second. However, scene complexity seems to be rising
even faster than rendering performance, with no end to even more
complex models in sight.
In this paper, we are targeting the interactive visualization of the
``Boeing 777'' model, a highly complex model of 350 \emph{million}
individual triangles, which -- due to its sheer size and complex
internal structure -- simply cannot be handled satisfactorily by
today's techniques. To render this model, we use a combination of
real-time ray tracing, a low-level out of core caching and demand
loading strategy, and a hierarchical, hybrid
volumetric/lightfield-like approximation scheme for representing
not-yet-loaded geometry.
%
With this approach, we are able to render the full
777 model at several frames per second even on a single
commodity desktop PC.
Eurographics
2004
Conference-Paper
http://edoc.mpg.de/231364
urn:ISBN:3-905673-12-6
Rendering Techniques 2004 : Eurographics Symposium on Rendering, Eurographics, 81-92 (2004)
en
oai:edoc.mpg.de:2313722012-09-1987:934
Multi-Video Compression in Texture Space
Ziegler, Gernot
Lensch, Hendrik P. A.
Ahmed, Naveed
Magnor, Marcus
Seidel, Hans-Peter
We present a model-based approach to encode multiple synchronized
video streams depicting a dynamic scene from different viewpoints.
With approximate 3D scene geometry available, we compensate for
motion as well as disparity by transforming all video images
to object textures prior to compression.
A two-level hierarchical coding strategy is employed to efficiently
exploit inter-texture coherence as well as to ensure quick random
access during decoding.
Experimental validation shows that attainable compression ratios
range up to 50:1 without subsampling.
The proposed coding scheme is intended for use in conjunction with
Free-Viewpoint Video and 3D-TV applications.
IEEE
2004
Conference-Paper
http://edoc.mpg.de/231372
urn:ISBN:0-7803-8555-1
11th IEEE International Conference on Image Processing (ICIP 2004), IEEE, 2467-2470 (2004)
en
oai:edoc.mpg.de:2318132012-09-1987:934
A flexible framework for learning-based Surface Reconstruction
Saleem, Waqar
The problem of Surface Reconstruction arises in many real world situations. We
introduce in detail the problem itself and then take a brief look into its
applications and existing techniques, particularly learning based techniques,
developed for its solution. Having presented the context, we closely examine
one such learning based technique – the Neural Mesh algorithm for Surface
Reconstruction.
Despite being relatively recent, the Neural Mesh algorithm has already
undergone several revisions, thus giving rise to several variants of the
original algorithm. We study the algorithm and each of its variants in detail.
All variants rely in varying
degrees on a specific aspect of the algorithm – a signal counter. We observe
that algorithmic reliance on the signal counter impedes performance and propose
an alternate way of performing the same functionalities – using a list.
Additionally, on the practical side, we identify areas where inhouse
implementations of the algorithms were wanting in efficiency and revise those
areas.
Changing over from the signal counter to the list represents a change in
approach from the exact learning of the original algorithms to a comparative
learning framework. We show empirically that this change in approach does not
produce any significant difference in the quality of the algorithms’ output,
while performance, in terms of running time, increases dramatically.
Universität des Saarlandes
2004
Thesis
http://edoc.mpg.de/231813
en
oai:edoc.mpg.de:2318612012-09-1987:934
Reconstruction of Volume Data with Quadratic Super Splines
Rössl, Christian
Zeilfelder, Frank
Nürnberger, Günther
Seidel, Hans-Peter
We propose a new approach to reconstruct nondiscrete models from gridded volume
samples. As a model, we use quadratic trivariate super splines on a uniform
tetrahedral partition. We discuss the smoothness and approximation properties
of our model and compare to alternative piecewise polynomial constructions. We
observe as a non-standard phenomenon that the derivatives of our splines yield
optimal approximation order for smooth data, while the theoretical error of the
values is nearly optimal due to the averaging rules. Our approach enables
efficient reconstruction and visualization of the data. As the piecewise
polynomials are of the lowest possible total degree two, we can efficiently
determine exact ray intersections with an iso-surface for ray-casting.
Moreover, the optimal approximation properties of the derivatives allow to
simply sample the necessary gradients directly from the polynomial pieces of
the splines. Our results confirm the efficiency of the quasi-interpolating
method and demonstrate high visual quality for rendered isosurfaces.
2004
Article
http://edoc.mpg.de/231861
IEEE Transactions on Visualization and Computer Graphics, v.10, 397-409 (2004)
en
oai:edoc.mpg.de:2318802012-09-1987:934
Realtime Ray Tracing and Interactive Global Illumination
Wald, Ingo
Universität des Saarlandes
2004
PhD-Thesis
http://edoc.mpg.de/231880
en
oai:edoc.mpg.de:2318812012-09-1987:934
Towards Real-Time Novel View Synthesis Using Visual Hulls
Li, Ming
This thesis discusses fast novel view synthesis from multiple images taken
from different viewpoints. We propose several new algorithms that take advantage
of modern graphics hardware to create novel views. Although different approaches
are explored, one geometry representation, the visual hull, is employed
throughout our work.
First the visual hull plays an auxiliary role and assists in reconstruction of
depth maps that are utilized for novel view synthesis. Then we treat the visual
hull as the principal geometry representation of scene objects. A
hardwareaccelerated
approach is presented to reconstruct and render visual hulls directly
from a set of silhouette images. The reconstruction is embedded in the rendering
process and accomplished with an alpha map trimming technique. We go on by
combining this technique with hardware-accelerated CSG reconstruction to improve
the rendering quality of visual hulls. Finally, photometric information is
exploited to overcome an inherent limitation of the visual hull. All algorithms
are implemented on a distributed system. Novel views are generated at
interactive
or real-time frame rates.
Universität des Saarlandes
2005
PhD-Thesis
http://edoc.mpg.de/231881
en
oai:edoc.mpg.de:2318922012-09-1987:934
DISCO - Acquisition of Translucent Objects
Goesele, Michael
Lensch, Hendrik P. A.
Lang, Jochen
Fuchs, Christian
Seidel, Hans-Peter
Marks, Joe
Translucent objects are characterized by diffuse light scattering
beneath the object's surface. Light enters and leaves an object at
possibly distinct surface locations. This paper presents the first
method to acquire this transport behavior for arbitrary
inhomogeneous objects. Individual surface points are illuminated in
our DISCO measurement facility and the object's impulse response is
recorded with a high-dynamic range video camera. The acquired data
is resampled into a hierarchical model of the object's light
scattering properties. Missing values are consistently interpolated
resulting in measurement-based, complete and accurate
representations of real translucent objects which can be rendered
with various algorithms.
2004
Article
http://edoc.mpg.de/231892
urn:ISSN:0730-0301
ACM Transactions on Graphics, v.23, 835-844 (2004)
en
oai:edoc.mpg.de:2318982012-09-1987:934
Topology Preserving Thinning of Vector Fields on Triangular Meshes
Theisel, Holger
Rössl, Christian
Seidel, Hans-Peter
Dodgson, Neil A.
Floater, Michael S.
Sabin, Malcom A.
We consider the topology of piecewise linear vector fields whose domain is a
piecewise linear 2-manifold, i.e. a triangular mesh. Such vector fields can
describe simulated 2-dimensional flows, or they may reflect geometric
properties of the underlying mesh. We introduce a thinning technique which
preserves the complete topology of the vector field, i.e. the critical points
and separatrices. As the theoretical foundation, we have shown in an earlier
paper that for local modiØcations of a vector field, it is possible to decide
entirely by a local analysis whether or not the global topology is preserved.
This result is applied in a number of compression algorithms which are based on
a repeated local modification of the vector field, namely a repeated
edge-collapse of the underlying piecewise linear domain.
Springer
2004
InBook
http://edoc.mpg.de/231898
urn:ISBN:3-540-21462-3
Advances in Multiresolution for Geometric Modelling, 353-366 (2004)
en
oai:edoc.mpg.de:2319032012-09-1987:934
An Interactive Out-of-Core Rendering Framework for Visualizing Massively Complex Models
Wald, Ingo
Dietrich, Andreas
Slusallek, Philipp
Keller, Alexander
Jensen, Henrik Wann
With the tremendous advances in both hardware capabilities and
rendering algorithms, rendering performance is steadily increasing.
Even consumer graphics hardware can render many million
triangles per second. However, scene complexity seems to be rising
even faster than rendering performance, with no end to even more
complex models in sight.
In this paper, we are targeting the interactive visualization of the
``Boeing 777'' model, a highly complex model of 350 \emph{million}
individual triangles, which -- due to its sheer size and complex
internal structure -- simply cannot be handled satisfactorily by
today's techniques. To render this model, we use a combination of
real-time ray tracing, a low-level out of core caching and demand
loading strategy, and a hierarchical, hybrid
volumetric/lightfield-like approximation scheme for representing
not-yet-loaded geometry.
%
With this approach, we are able to render the full
777 model at several frames per second even on a single
commodity desktop PC.
Eurographics
2004
Conference-Paper
http://edoc.mpg.de/231903
urn:ISBN:3-905673-12-6
Rendering Techniques 2004 : Eurographics Symposium on Rendering, Eurographics, 81-92 (2004)
en
oai:edoc.mpg.de:2319102012-09-1987:934
New Acquisition Techniques for Real Objects and Light Sources in Computer Graphics
Goesele, Michael
Accurate representations of objects and light sources in a scene model are a
crucial prerequisite for realistic image synthesis using computer graphics
techniques. This thesis presents techniques for the efficient acquisition of
real world objects and real world light sources, as well as an assessment of
the quality of the acquired
models.
Making use of color management techniques, we setup an appearance reproduction
pipeline that ensures best-possible reproduction of local light reflection with
the available input and output devices. We introduce a hierarchical model for
the subsurface light transport in translucent objects, derive an acquisition
methodology, and acquire models of several translucent objects that can be
rendered interactively. Since geometry models of real world objects are often
acquired using 3D range scanners, we also present a method based on the concept
of modulation transfer functions to evaluate their accuracy.
In order to illuminate a scene with realistic light sources, we propose a
method to acquire a model of the near-field emission pattern of a light source
with optical prefiltering. We apply this method to several light sources with
different emission characteristics and demonstrate the integration of the
acquired models into both, global illumination as well as hardware-accelerated
rendering systems.
Universität des Saarlandes
2004
PhD-Thesis
http://edoc.mpg.de/231910
en
oai:edoc.mpg.de:2319132012-09-1987:934
Importance Sampling in Photon Tracing
Yu, Hang
All global illumination algorithms are based on rendering equation. The
rendering equation is solved in different ways in every algorithm. Most of
algorithms solve the equation by using Monte Carlo method. In this process many
samples are produced. These samples have different contribution to generated
image. If one hopes to get acceptable result with fewer samples, important
samples, which have more contribution for the nal image, must be considered in
the rst place. For example, in ordinary Light Tracing, millions of photons
have to be traced in order to obtain the distribution of illumination in the
whole scene. Actually only a part of scene can be observed most of the time,
and just photons hitting visible surfaces will contribute to the generated
image. If only a small part of entire scene is visible, we will spend most of
the time tracing and storing unimportant photons that have no any contribution
to the nal image. Even considering only visible photons, one can see that
their contribution to image is very different. Surfaces that are located closer
to viewpoint have larger image plane projected area and thus require more
photons to achieve the same noise level as surfaces located further away.
Orientation of surface in respect to view direction also affects viewdependent
photons importance. Depending on the application and used Monte Carlo algorithm
one can come up with many other different criteria to compute this importance,
which may dramatically affect the quality of produced images and computation
speed. Algorithm presented in the thesis takes only useful (visible) photons
into account, concentrating computation only on the surfaces visible by
currently active camera, balancing the distribution of photons on the image
plane, greatly improving the image quality. Using this concept, we can get
better result with fewer photons. In this way it is possible to save not only
rendering time, but also storage space because less photons need to be stored.
This idea also can be applied in other algorithms where millions of samples
have to be generated. Once the difference among these samples is found out, we
can pay more attention to the important samples that have more contribution to
the result image, while ignoring less important ones, thus using fewer samples
to get better result.
Universität des Saarlandes
2004
Thesis
http://edoc.mpg.de/231913
en
oai:edoc.mpg.de:2319302012-09-1987:934
Normal Based Estimation of the Curvature Tensor for Triangular Meshes
Theisel, Holger
Rössl, Christian
Zayer, Rhaleb
Seidel, Hans-Peter
Cohen-Or, Daniel
Ko, Hyeong-Seok
Terzopoulos, Demetri
Warren, Joe
We introduce a new technique for estimating the curvature tensor of a
triangular mesh. The input of the algorithm is only a single triangle equipped
with its (exact or estimated) vertex normals. This way we get a smooth function
of the curvature tensor inside each triangle of the mesh. We show that the
error of the new method is comparable with the error of a cubic fitting
approach if the incorporated normals are estimated. If the exact normals of the
underlying surface are available at the vertices, the error drops signifi-
cantly. We demonstrate the applicability of the new estimation at a rather
complex data set.
IEEE
2004
Conference-Paper
http://edoc.mpg.de/231930
urn:ISBN:0-7695-2234-3
12th Pacific Conference on Computer Graphics and Applications, PG 2004, IEEE, 288-297 (2004)
en
oai:edoc.mpg.de:2319322012-09-1987:934
Laplacian Surface Editing
Sorkine, Olga
Lipman, Yaron
Cohen-Or, Daniel
Alexa, Marc
Rössl, Christian
Seidel, Hans-Peter
Scopigno, Roberto
Zorin, Denis
Fellner, Dieter
Spencer, Stephen
Surface editing operations commonly require geometric details of the surface to
be preserved as much as possible. We argue that geometric detail is an
intrinsic property of a surface and that, consequently, surface editing is best
performed by operating over an intrinsic surface representation. We provide
such a representation of a surface, based on the Laplacian of the mesh, by
encoding each vertex relative to its neighborhood. The Laplacian of the mesh is
enhanced to be invariant to locally linearized rigid transformations and
scaling. Based on this Laplacian representation, we develop useful editing
operations: interactive free-form deformation in a region of interest based on
the transformation of a handle, transfer and mixing of geometric details
between two surfaces, and transplanting of a partial surface mesh onto another
surface. The main computation involved in all operations is the solution of a
sparse linear system, which can be done at interactive rates. We demonstrate
the effectiveness of our approach in several examples, showing that the editing
operations change the shape while respecting the structural geometric detail.
Eurographics
2004
Conference-Paper
http://edoc.mpg.de/231932
urn:ISBN:3-905673-13-4/1727-8384
SGP 2004 (SGP-04) : Symposium on Geometry Processing, Eurographics, 179-188,274 (2004)
en
oai:edoc.mpg.de:2319352012-09-1987:934
Realtime Caustics using Distributed Photon Mapping
Günther, Johannes
Wald, Ingo
Slusallek, Philipp
Keller, Alexander
Jensen, Henrik Wann
With the advancements in realtime ray tracing and new global illumination
algorithms we are now able to render the most important illumination effects at
interactive rates. One of the major remaining issues is the fast and efficient
simulation of caustic illumination, such as e.g. the illumination from a car
headlight. The photon mapping algorithm is a simple and robust approach that
generates high-quality results and is the preferred algorithm for computing
caustic illumination. However, photon mapping has a number of properties that
make it rather slow on today s processors. Photon mapping has also been
notoriously difficult to parallelize efficiently.
In this paper, we present a detailed analysis of the performance issues of
photon mapping together with signifi- cant performance improvements for all
aspects of the photon mapping technique. The solution forms a complete
framework for realtime photon mapping that efficiently combines realtime ray
tracing, optimized and improved photon mapping algorithms, and efficient
parallelization across commodity PCs. The presented system achieves realtime
photon mapping performance of up to 22 frames per second on non-trivial scenes,
while still allowing for interactively updating all aspects of the scene,
including lighting, material properties, and geometry.
Eurographics
2004
Conference-Paper
http://edoc.mpg.de/231935
urn:ISBN:3-905673-12-6
Rendering Techniques 2004 : Eurographics Symposium on Rendering, Eurographics, 111-121 (2004)
en
oai:edoc.mpg.de:2319362012-09-1987:934
Spline Approximation of General Volumetric Data
Rössl, Christian
Zeilfelder, Frank
Nürnberger, Günther
Seidel, Hans-Peter
Elber, Gershon
Patrikalakis, Nick
Brunet, Pere
We present an efficient algorithm for approximating huge general
volumetric data sets, i.e.~the data is given over arbitrarily shaped
volumes and consists of up to millions of samples. The method is based
on cubic trivariate splines, i.e.~piecewise polynomials of total
degree three defined w.r.t. uniform type-6 tetrahedral partitions of
the volumetric domain. Similar as in the recent bivariate
approximation approaches, the splines in three variables
are automatically determined from the discrete data as a result of a
two-step method, where local discrete least
squares polynomial approximations of varying degrees are extended by
using natural conditions, i.e.the continuity and smoothness properties
which determine the underlying spline space. The main advantages of
this approach with linear algorithmic complexity are as follows: no
tetrahedral partition of the volume data is needed, only small
linear systems have to be solved, the local variation and
distribution of the data is automatically adapted,
Bernstein-B{\'e}zier techniques well-known in Computer Aided
Geometric Design (CAGD) can be fully exploited, noisy data are
automatically smoothed. Our numerical examples with huge data sets
for synthetic data as well as some real-world data confirm the
efficiency of the methods, show the high quality of the spline
approximation, and illustrate that the rendered iso-surfaces inherit
a visual smooth appearance from the volume approximating splines.
Eurographics
2004
Conference-Paper
http://edoc.mpg.de/231936
urn:ISBN:3-905673-55-X
Proceedings of the 9th ACM Symposium on Solid Modeling and Applications (SM 2004), Eurographics, 71-82 (2004)
en
oai:edoc.mpg.de:2319382012-09-1987:934
Visible Difference Predictor for High Dynamic Range Images
Mantiuk, Rafal
Myszkowski, Karol
Seidel, Hans-Peter
Thissen, Wil
Wieringa, Peter
Pantic, Maja
Ludema, Marcel
Since new imaging and rendering systems commonly use physically
accurate lighting information in the form of High-Dynamic Range
data, there is a need for an automatic visual quality assessment of the
resulting images. In this work we extend the Visual Difference Predictor (VDP)
developed by Daly to handle HDR data. This let us predict if a human observer
is able to perceive differences for a pair of HDR images under the adaptation
conditions corresponding to the real scene observation.
IEEE
2004
Conference-Paper
http://edoc.mpg.de/231938
urn:ISBN:0-7803-8567-5
2004 IEEE International Conference on Systems, Man & Cybernetics, IEEE, 2763-2769 (2004)
en
oai:edoc.mpg.de:2319482012-09-1987:934
Perception-motivated High Dynamic Range Video Encoding
Mantiuk, Rafal
Krawczyk, Grzegorz
Myszkowski, Karol
Seidel, Hans-Peter
Marks, Joe
Due to rapid technological progress in high dynamic range (HDR)
video capture and display, the efficient storage and
transmission of such data is crucial for the completeness of any HDR
imaging pipeline. We propose a new approach for
inter-frame encoding of HDR video, which is embedded in the
well-established MPEG-4 video compression standard. The key
component of our technique is luminance quantization
that is optimized for the contrast threshold perception in the
human visual system. The quantization
scheme requires only 10--11 bits to encode 12 orders of magnitude of
visible luminance range and does not lead to perceivable contouring
artifacts. Besides video encoding, the proposed quantization
provides perceptually-optimized luminance sampling for fast
implementation of any
global tone mapping operator using a lookup table.
To improve the quality of synthetic video sequences, we introduce
a coding scheme for discrete cosine transform (DCT) blocks with
high contrast. We demonstrate the capabilities of HDR video in
a player, which enables decoding, tone mapping, and applying
post-processing effects in real-time. The tone mapping algorithm as well
as its parameters can be changed interactively while the video is playing.
We can simulate post-processing
effects such as glare, night vision, and motion blur, which appear
very realistic due to the usage of HDR data.
2004
Article
http://edoc.mpg.de/231948
urn:ISSN:0730-0301
ACM Transactions on Graphics, v.23, 733-741 (2004)
en
oai:edoc.mpg.de:2319512012-09-1987:934
Differential Coordinates for Interactive Mesh Editing
Lipman, Yaron
Sorkine, Olga
Cohen-Or, Daniel
Levin, David
Rössl, Christian
Seidel, Hans-Peter
Giannini, Franca
Pasko, Alexander
One of the main challenges in editing a mesh is to retain the visual appearance
of the surface after applying various modifications. In this paper we advocate
the use of linear differential coordinates as means to preserve the
high-frequency detail of the surface. The differential coordinates represent
the details and are defined by a linear transformation of the mesh vertices.
This allows the reconstruction of the edited surface by solving a linear system
that satisfies the reconstruction of the local details in least squares sense.
Since the differential coordinates are defined in a global coordinate system
they are not rotation-invariant. To compensate for that, we rotate them to
agree with the rotation of an approximated local frame. We show that the linear
least squares system can be solved fast enough to guarantee interactive
response time thanks to a precomputed factorization of the coefficient matrix.
We demonstrate that our approach enables to edit complex detailed meshes while
keeping the shape of the details in their natural orientation.
IEEE
2004
Conference-Paper
http://edoc.mpg.de/231951
urn:ISBN:0-7695-1909-1
Shape Modeling International 2004 (SMI 2004), IEEE, 181-190 (2004)
en
oai:edoc.mpg.de:2378602012-09-1987:934
Faster ray tracing with SIMD shaft culling
Dmitriev, Kirill
Havran, Vlastimil
Seidel, Hans-Peter
Max-Planck-Institut für Informatik
2004
Report
http://edoc.mpg.de/237860
en
oai:edoc.mpg.de:2378622012-09-1987:934
Neural meshes : surface reconstruction with a learning algorithm
Ivrissimtzis, Ioannis
Jeong, Won-Ki
Lee, Seungyong
Lee, Yunjin
Seidel, Hans-Peter
Max-Planck-Institut für Informatik
2004
Report
http://edoc.mpg.de/237862
en
oai:edoc.mpg.de:2378632012-09-1987:934
r-Adaptive parameterization of surfaces
Zayer, Rhaleb
Rössl, Christian
Seidel, Hans-Peter
Max-Planck-Institut für Informatik
2004
Report
http://edoc.mpg.de/237863
en
oai:edoc.mpg.de:2378642012-09-1987:934
Modeling hair using a wisp hair model
Haber, Jörg
Schmitt, Carina
Koster, Martin
Seidel, Hans-Peter
Max-Planck-Institut für Informatik
2004
Report
http://edoc.mpg.de/237864
en
oai:edoc.mpg.de:2789512012-09-1987:934
Discrete Tensorial Quasi-Harmonic Maps
Zayer, Rhaleb
Rössl, Christian
Seidel, Hans-Peter
Spagnuolo, Michaela
Pasko, Alexander
Belyaev, Alexander
We introduce new linear operators for surface parameterization.
Given an initial mapping from the parametric plane onto a surface mesh, we
establish a secondary map of the plane onto itself that mimics the initial
one.
The resulting low-distortion parameterization is smooth as it stems from
solving a quasi-harmonic equation.
Our parameterization method is robust and independent of (the quality of) the
initial map.
In fact, for most cases the methods converges from a simple projection on the
least squares plane even for complex models.
IEEE
2005
Conference-Paper
http://edoc.mpg.de/278951
Shape Modeling International 2005 (SMI 2005), IEEE, 276-285 (2005)
en
oai:edoc.mpg.de:2789532012-09-1987:934
Setting the Boundary Free: A Composite Approach to Surface Parameterization
Zayer, Rhaleb
Rössl, Christian
Seidel, Hans-Peter
Desbrun, Mathieu
Pottmann, Helmut
In the last decade, surface mesh parameterization has emerged as a standard
technique in computer graphics. The ever increasing need for processing large
and highly detailed data sets fosters the development of ef cient
parameterization techniques that can capture the geometry of the input meshes
and produce low distortion planar maps. We present a set of novel techniques
allowing for low distortion parameterization. In particular, we address one of
the major shortcomings of linear methods by allowing the parametric
representation to evolve freely on the plane without any fixed boundary
vertices. Our method consists of several simple steps, each solving a linear
problem. Our results exhibit a fair balance between high-quality and
computational ef ciency.
Eurographics/ACM
2005
Conference-Paper
http://edoc.mpg.de/278953
Symposium on Geometry Processing, Eurographics/ACM, 91-100 (2005)
en
oai:edoc.mpg.de:2789542012-09-1987:934
Harmonic Guidance for Surface Deformation
Zayer, Rhaleb
Rössl, Christian
Karni, Zachi
Seidel, Hans-Peter
Alexa, Marc
Marks, Joe
We present an interactive method for applying deformations to a
surface mesh while preserving its global shape and local properties.
Two surface editing scenarios are discussed, which conceptually
differ in the specification of deformations:
Either interpolation constraints are imposed explicitly, e.g., by
dragging a subset of vertices, or, deformation of a reference
surface is mimicked.
The contribution of this paper is a novel approach for interpolation
of local deformations over the manifold and for efficiently
establishing correspondence to a reference surface from only few
pairs of markers.
As a general tool for both scenarios, a harmonic field is
constructed to guide the interpolation of constraints and to find
correspondence required for deformation transfer.
We show that our approach fits nicely in a unified mathematical
framework, where the same type of linear operator is applied in all
phases, and how this approach can be used to create an intuitive and
interactive editing tool.
Blackwell
2005
Conference-Paper
http://edoc.mpg.de/278954
The European Association for Computer Graphics 26th Annual Conference : EUROGRAPHICS 2005, Blackwell, 601-609 (2005)
en
oai:edoc.mpg.de:2789612012-09-1987:934
Feature Sensitive Mesh Segmentation with Mean Shift
Yamauchi, Hitoshi
Lee, Seungyong
Lee, Yunjin
Ohtake, Yutaka
Belyaev, Alexander
Seidel, Hans-Peter
Spagnuolo, Michaela
Pasko, Alexander
Belyaev, Alexander
Feature sensitive mesh segmentation is important for many
computer graphics and geometric modeling applications. In this
paper, we develop a mesh segmentation method which is capable of
producing high-quality shape partitioning. It respects fine shape
features and works well on various types of shapes, including
natural shapes and mechanical parts.
The method combines a procedure for clustering mesh normals
with a modification of the mesh chartification technique \cite{Sander_sig03}.
For clustering of mesh normals, we adapt Mean Shift,
a powerful general purpose technique for clustering scattered data.
We demonstrate advantages of our method by comparing it with two
state-of-the-art mesh segmentation techniques.
IEEE
2005
Conference-Paper
http://edoc.mpg.de/278961
urn:ISBN:0-7695-2379-X
Shape Modeling International 2005 (SMI 2005), IEEE, 236-243 (2005)
en
oai:edoc.mpg.de:2789652012-09-1987:934
Extracting higher order critical points and topological simplification of 3D vector fields
Weinkauf, Tino
Theisel, Holger
Shi, Kuangyu
Hege, Hans-Christian
Seidel, Hans-Peter
Silva, Cláudio T.
Gröller, Eduard
Rushmeier, Holly
IEEE
2005
Conference-Paper
http://edoc.mpg.de/278965
IEEE Visualization 2005 (VIS 2005), IEEE, 559-566 (2005)
en
oai:edoc.mpg.de:2789682012-09-1987:934
Topological Methods for 2D Time-Dependent Vector Fields Based on Stream Lines and Path Lines
Theisel, Holger
Weinkauf, Tino
Hege, Hans-Christian
Seidel, Hans-Peter
2005
Article
http://edoc.mpg.de/278968
urn:ISSN:1077-2626
IEEE Transactions on Visualization and Computer Graphics, v.11, 383-394 (2005)
en
oai:edoc.mpg.de:2789692012-09-1987:934
Extraction of parallel vector surfaces in 3D time-dependent fields and applications to vortex core line tracking
Theisel, Holger
Sahner, Jan
Weinkauf, Tino
Hege, Hans-Christian
Seidel, Hans-Peter
Silva, Cláudio T.
Gröller, Eduard
Rushmeier, Holly
IEEE
2005
Conference-Paper
http://edoc.mpg.de/278969
IEEE Visualization 2005 (VIS 2005), IEEE, 631-638 (2005)
en
oai:edoc.mpg.de:2789722012-09-1987:934
Visualization with Stylized Line Primitives
Stoll, Carsten
Gumhold, Stefan
Seidel, Hans-Peter
Silva, Cláudio T.
Gröller, Eduard
Rushmeier, Holly
Line primitives are a very powerful visual attribute used for scientific
visualization and in particular for 3D vector-field visualization.
We extend the basic line primitives with additional visual attributes
including color, line width, texture and orientation. To implement
the visual attributes we represent the stylized line primitives as generalized
cylinders. One important contribution of our work is an efficient
rendering algorithm for stylized lines, which is hybrid in the
sense that it uses both CPU and GPU based rendering. We improve
the depth perception with a shadow algorithm. We present several
applications for the visualization with stylized lines among which
are the visualizations of 3D vector fields and molecular structures.
IEEE
2005
Conference-Paper
http://edoc.mpg.de/278972
IEEE Visualization 2005 (VIS 2005), IEEE, 695-702 (2005)
en
oai:edoc.mpg.de:2789752012-09-1987:934
Animosaics
Smith, Kaleigh
Liu, Yunjun
Klein, Allison
Anjyo, Ken
Faloutsos, Petros
Animated mosaics are a traditional form of stop-motion animation created by
arranging and rearranging small objects or tiles from frame to frame. While
this animation style is uniquely compelling, the traditional process of
manually placing and then moving tiles in each frame is time-consuming and
labourious. Recent work has proposed algorithms for static mosaics, but
generating temporally coherent mosaic animations has remained open. In
addition, previous techniques for temporal coherence allow non-photorealistic
primitives to layer, blend, deform, or scale, techniques that are unsuitable
for mosaic animations. This paper presents
a new approach to temporal coherence and applies this to build a method for
creating mosaic animations. Specifically, we characterize temporal coherence as
the
coordinated movement of groups of primitives. We describe a system for
achieving this coordinated movement to create temporally coherent geometric
packings of 2D shapes over time. We also show how to create static mosaics
comprised of different tile shapes using area-based centroidal Voronoi
diagrams.
ACM
2005
Conference-Paper
http://edoc.mpg.de/278975
urn:ISBN:1-7695-2270-X
Computer Animation 2005 : ACM SIGGRAPH / Eurographics Symposium on Computer Animation, ACM, 201-208 (2005)
en
oai:edoc.mpg.de:2789762012-09-1987:934
Fast Visualization by Shear-Warp on Quadratic Super-Spline Models Using Wavelet Data Decompositions
Schlosser, Gregor
Hesser, Jürgen
Zeilfelder, Frank
Rössl, Christian
Männer, Reinhard
Nürnberger, Günther
Seidel, Hans-Peter
Silva, Cláudio T.
Gröller, Eduard
Rushmeier, Holly
IEEE
2005
Conference-Paper
http://edoc.mpg.de/278976
urn:ISBN:0-7803-9462-3
16th IEEE Visualization Conference (VIS 2005), IEEE, 351-358 (2005)
en
oai:edoc.mpg.de:2789782012-09-1987:934
Surface from Scattered Points: A Brief Survey of Recent Developments
Schall, Oliver
Samozino, Marie
Falcidieno, Bianca
Magnenat-Thalmann, Nadia
The paper delivers a brief overview of recent developments in
the field of surface reconstruction from scattered point data.
The focus is on computational geometry methods, implicit surface
interpolation techniques, and shape learning approaches.
MIRALab
2005
Conference-Paper
http://edoc.mpg.de/278978
1st International Workshop towards Semantic Virtual Environments, MIRALab, 138-147 (2005)
en
oai:edoc.mpg.de:2789792012-09-1987:934
Robust Filtering of Noisy Scattered Point Data
Schall, Oliver
Belyaev, Alexander
Seidel, Hans-Peter
Pauly, Mark
Zwicker, Matthias
In this paper, we develop a method for robust filtering of a
noisy set of points sampled from a smooth surface. The main idea
of the method consists of using a kernel density estimation
technique for point clustering. Specifically, we use a
mean-shift based clustering procedure. With every point of the
input data we associate a local likelihood measure capturing the
probability that a 3D point is located on the sampled surface.
The likelihood measure takes into account the normal directions
estimated at the scattered points. Our filtering procedure
suppresses noise of different amplitudes and allows for an easy
detection of outliers which are then automatically removed by
simple thresholding. The remaining set of maximum likelihood
points delivers an accurate point-based approximation of the
surface. We also show that while some established meshing
techniques often fail to reconstruct the surface from original
noisy point scattered data, they work well in conjunction with
our filtering method.
Eurographics Association
2005
Conference-Paper
http://edoc.mpg.de/278979
IEEE/Eurographics Symposium on Point-Based Graphics, Eurographics Association, 71-77 (2005)
en
oai:edoc.mpg.de:2789822012-09-1987:934
Pose Estimation of Free-form Contours
Rosenhahn, Bodo
Perwass, Christian
Sommer, Gerald
In this article we discuss the 2D-3D pose estimation problem of 3D free-form
contours. In our scenario we observe objects of any 3D shape in an image of a
calibrated camera. Pose estimation means to estimate the relative position and
orientation (containing a rotation and translation) of the 3D object to the
reference camera system. The fusion of modeling free-form contours within the
pose estimation problem is achieved by using the conformal geometric algebra.
The conformal geometric algebra is a geometric algebra which models entities as
stereographically projected entities in a homogeneous model. This leads to a
linear description of kinematics on the one hand and projective geometry on the
other hand. To model free-form contours in the conformal framework we use
twists to model cycloidal curves as twist-depending functions and interpret
n-times nested twist generated curves as functions generated by 3D Fourier
descriptors. This means, we use the twist concept to apply a spectral domain
representation of 3D contours within the pose estimation problem. We will show
that twist representations of objects can be numerically efficient and easily
be applied to the pose estimation problem. The pose problem itself is
formalized as implicit problem and we gain constraint equations, which have to
be fulfilled with respect to the unknown rigid body motion. Several experiments
visualize the robustness and real-time performance of our algorithms.
Springer
2005
Article
http://edoc.mpg.de/278982
urn:ISSN:0920-5691
International Journal of Computer Vision, v.62, 267-289 (2005)
en
oai:edoc.mpg.de:2789832012-09-1987:934
A system for marker-less human motion estimation
Rosenhahn, Bodo
Kersting, Uwe
Smith, Andrew
Gurney, Jason
Brox, Thomas
Klette, Reinhard
Kropatsch, Walter
Sablatnig, Robert
Hanbury, Allan
In this contribution we present a silhouette based human
motion estimation system. The system components contain silhouette
extraction based on level sets, a correspondence module, which relates
image data to model data and a pose estimation module. Experiments are
done in a four camera setup and we estimate the model components with
21 degrees of freedom in two frames per second.
Finally, we perform a comparison of the
motion estimation system with a marker based tracking
system to perform a quantitative error analysis. The results show the
applicability of the system for marker-less sports movement analysis.
Springer
Springer
2005
Conference-Paper
http://edoc.mpg.de/278983
urn:ISBN:3-540-28703-5
Pattern recognition : 27th DAGM Symposium, Springer, 230-237 (2005)
en
oai:edoc.mpg.de:2789862012-09-1987:934
New Techniques for the Modeling, Processing and Visualization of Surfaces and Volumes
Rössl, Christian
Universität des Saarlandes
2005
PhD-Thesis
http://edoc.mpg.de/278986
en
oai:edoc.mpg.de:2789872012-09-1987:934
Faces and Hands: Modeling and Animating Anatomical and Photorealistic Models with Regard to the Communicative Competence of Virtual Humans
Albrecht, Irene
In order to be believable, virtual human characters must be able to
communicate in a human-like fashion realistically. This dissertation
contributes to improving and automating several aspects of virtual
conversations.
We have proposed techniques to add non-verbal speech-related facial
expressions to audiovisual speech, such as head nods for of emphasis.
During conversation, humans experience shades of emotions much more frequently
than the strong Ekmanian basic emotions. This prompted us to develop a method
that interpolates between facial expressions of emotions to create new ones
based on an emotion model.
In the area of facial modeling, we have presented a system to generate
plausible 3D face models from vague mental images. It makes use of a morphable
model of faces and exploits correlations among facial features.
The hands also play a major role in human communication. Since the basis for
every realistic animation of gestures must be a convincing model of the hand,
we devised a physics-based anatomical hand model, where a hybrid muscle model
drives the animations. The model was used to visualize complex hand movement
captured using multi-exposure photography.
Universität des Saarlandes
2005
PhD-Thesis
http://edoc.mpg.de/278987
en
oai:edoc.mpg.de:2789902012-09-1987:934
Texture driven pose estimation
Rosenhahn, Bodo
Ho, Harvey
Klette, Reinhard
Sarfraz, M
Wand, Y
Banissi, E
This article presents a 2D-3D pose estimation algorithm which relies on
texture information on the surface mesh of an object model. The textured
surface mesh is rendered in a virtual image
and a modified block matching algorithm is applied to determine correspondences
between midpoints of
surface patches to points in an image. This is used in a point-based 2D-3D pose
estimation algorithm
to determine the pose and orientation of a 3D object with respect to given
image data.
We present experiments on various image sequences and show
advantages of the chosen approach (e.g., in the context of varying
backgrounds, noise or partial occlusions).
IEEE
2005
Conference-Paper
http://edoc.mpg.de/278990
urn:ISBN:0-7695-2392-7
Computer Graphics, Imaging and Visualization : New Trends (CGIV 05), IEEE, 271-277 (2005)
en
oai:edoc.mpg.de:2789912012-09-1987:934
Automatic human model generation
Rosenhahn, Bodo
He, Lei
Klette, Reinhard
Gagalowicz, Andre
Philips, Wilfried
The contribution presents an integrated system for automatic
acquisition of a human torso model, using different input images.
The output model consists of two free-form surface patches (with
texture maps) for the
torso and the arms. Also, the positions for the neck joint on the
torso, and six joint positions on the arms (for the wrist, elbow
and shoulder) are determined automatically. We present reconstruction
results, and, as application, a simple tracking system for arm movements.
Springer
Springer
2005
Conference-Paper
http://edoc.mpg.de/278991
urn:ISBN:3-540-28969-0
Computer analysis of images and patterns : 11th International Conference, CAIP 2005, Versailles, France, September 5-8, 2005
Computer Analysis of Images and Patterns 11th Int. Conference, Springer, 41-48 (2005)
en
oai:edoc.mpg.de:2789922012-09-1987:934
Three-Dimensional Shape Knowledge for Joint Image Segmentation and Pose Estimation.
Rosenhahn, Bodo
Brox, Thomas
Weickert, Joachim
Kropatsch, Walter
Sablatnig, Robert
Hanbury, Allan
This paper presents the integration of 3D shape knowledge into a
variational model for level set based image segmentation and tracking.
Having a 3D surface model of an object that is visible in the image of a
calibrated camera, the object contour stemming from the segmentation is
applied to estimate the 3D pose parameters, whereas the object model
projected to the image plane helps in a top-down manner to improve the
extraction of the contour and the region statistics. The present approach
clearly states all model assumptions in a single energy functional. This
keeps the model manageable and allows further extensions for the future.
While common alternative segmentation approaches that integrate 2D shape
knowledge face the problem that an object can look very different from
various viewpoints, a 3D free form model ensures that for each view the
model can perfectly fit the data in the image. Moreover, one solves the
higher level problem of determining the object pose including its distance
to the camera. Experiments demonstrate the performance of the method.
Springer
Springer
2005
Conference-Paper
http://edoc.mpg.de/278992
urn:ISBN:3-540-28703-5
Pattern recognition : 27th DAGM Symposium, Springer, 109-116 (2005)
en
oai:edoc.mpg.de:2789982012-09-1987:934
A perceptual framework for contrast processing of high dynamic range images
Mantiuk, Rafal
Myszkowski, Karol
Seidel, Hans-Peter
Malik, Jitendra
Koenderink, Jan J.
In this work we propose a framework for image processing in a visual
response space, in which contrast values directly correlate with
their visibility in an image. Our framework involves a
transformation of an image from luminance space to a pyramid of
low-pass contrast images and then to the visual response space.
After modifying response values, the transformation can be reversed
to produce the resulting image. To predict the visibility of
suprathreshold contrast, we derive a transducer function for the
full range of contrast levels that can be found in High Dynamic
Range images. We show that a complex contrast compression operation,
which preserves textures of small contrast, is reduced to a linear
scaling in the proposed visual response space.
ACM
2005
Conference-Paper
http://edoc.mpg.de/278998
urn:ISBN:1-59593-139-2
APGV '05: Proceedings of the 2nd symposium on Appied perception in graphics and visualization, ACM, 87-94 (2005)
en
oai:edoc.mpg.de:2790032012-09-1987:934
Asymptotic Analysis of Discrete Normals and Curvatures of Polylines
Langer, Torsten
Belyaev, Alexander
Seidel, Hans-Peter
Jüttler, Bert
Accurate estimations of geometric properties of a smooth curve from
its discrete approximation are important for many computer graphics and
computer vision applications.
To assess and improve the quality of such an approximation, we assume that the
curve is known in general form. Then we can represent the
curve by a Taylor series expansion
and compare its geometric properties with the corresponding discrete
approximations. In turn
we can either prove convergence of these approximations towards the true
properties
as the edge lengths tend to zero, or we can get hints on how
to eliminate the error.
In this paper, we propose and study discrete schemes for estimating tangent and
normal vectors as well as
for estimating curvature and torsion of a smooth 3D curve approximated by a
polyline.
Thereby we make some interesting findings about connections between (smooth)
classical curves
and certain estimation schemes for polylines.
Comenius University
2005
Conference-Paper
http://edoc.mpg.de/279003
urn:ISBN:80-223-2057-9
21st Spring Conference on Computer Graphics (SCCG 2005), Comenius University, 221-224 (2005)
en
oai:edoc.mpg.de:2790042012-09-1987:934
Exact and Approximate Quadratures for Curvature Tensor Estimation
Langer, Torsten
Belyaev, Alexander
Seidel, Hans-Peter
Greiner, Günther
Hornegger, Joachim
Niemann, Heinrich
Stamminger, Marc
Accurate estimations of geometric properties of a surface from
its discrete approximation are important for many computer graphics and
geometric modeling applications.
In this paper,
we derive exact quadrature formulae for mean curvature,
Gaussian curvature, and the Taubin integral representation of the curvature
tensor.
The exact quadratures are then used to obtain reliable estimates
of the curvature tensor of a smooth surface approximated by a dense triangle
mesh. The proposed method is fast and
easy to implement. It is highly competitive with
conventional curvature tensor estimation approaches.
Additionally, we show that the curvature tensor approximated as proposed by us
converges towards the true curvature tensor as the edge lengths tend to zero.
Aka
Copyright: the editors of Vision, Modeling, and Visualization 2005
2005
Conference-Paper
http://edoc.mpg.de/279004
urn:ISBN:3-89838-068-8
Vision, Modeling, and Visualization 2005 (VMV'05), Aka, 421-428 (2005)
en
oai:edoc.mpg.de:2790052012-09-1987:934
Exact and Approximate Quadratures for Curvature Tensor Estimation
Langer, Torsten
Belyaev, Alexander
Seidel, Hans-Peter
Desbrun, Mathieu
Pottmann, Helmut
This is an electronic version of an Article published in the Poster Proceedings
of the Third Eurographics Symposium on Geometry Processing, Vienna, Austria,
July 4-6, 2005.
2006
Poster
http://edoc.mpg.de/279005
urn:ISBN:3-905673-24-X/1727-8384
en
oai:edoc.mpg.de:2790062012-09-1987:934
Asymptotic Analysis of Discrete Normals and Curvatures of Polylines
Langer, Torsten
Belyaev, Alexander
Seidel, Hans-Peter
Accurate estimations of geometric properties of a smooth curve from its
discrete approximation are important for many computer graphics and computer
vision applications. To assess and improve the quality of such an
approximation, we assume that the curve is known in general form. Then we can
represent the curve by a Taylor series expansion and compare its geometric
properties with the corresponding discrete approximations. In turn we can
either prove convergence of these approximations towards the true properties as
the edge lengths tend to zero, or we can get hints on how to eliminate the
error. In this paper, we propose and study discrete schemes for estimating
tangent and normal vectors as well as for estimating curvature and torsion of a
smooth 3D curve approximated by a polyline. Thereby we make some interesting
findings about connections between (smooth) classical curves and certain
estimation schemes for polylines.
ACM
2005
Conference-Paper
http://edoc.mpg.de/279006
urn:ISBN:80-223-2057-9
SCCG '05: Proceedings of the 21st spring conference on Computer graphics, ACM, 229-232 (2005)
en
oai:edoc.mpg.de:2790132012-09-1987:934
Clustering for Surface Reconstruction
Isgro, Francesco
Odone, Francesca
Saleem, Waqar
Schall, Oliver
Falcidieno, Bianca
Magnenat-Thalmann, Nadia
We consider applications of clustering techniques, Mean Shift and
Self-Organizing Maps, to surface reconstruction (meshing) from
scattered point data and review a novel kernel-based clustering
method.
MIRALab
2005
Conference-Paper
http://edoc.mpg.de/279013
1st International Workshop towards Semantic Virtual Environments, MIRALab, 156-162 (2005)
en
oai:edoc.mpg.de:2790272012-09-1987:934
Visualization of White Matter Tracts with Wrapped Streamlines
Enders, Frank
Sauber, Natascha
Merhof, Dorit
Hastreiter, Peter
Nimsky, Christopher
Stamminger, Marc
Silva, Cláudio T.
Gröller, Eduard
Rushmeier, Holly
Diffusion tensor imaging is a magnetic resonance imaging method
which has gained increasing importance in neuroscience and especially in
neurosurgery. It acquires diffusion properties represented by a symmetric 2nd
order tensor for each voxel in the gathered dataset. From the medical point of
view, the data is of special
interest due to different diffusion characteristics of varying brain tissue
allowing conclusions about the underlying structures such as white matter
tracts. An obvious way to visualize this data is
to focus on the anisotropic areas using the major eigenvector for
tractography and rendering lines for visualization of the simulation results.
Our approach extends this technique to avoid line representation since lines
lead to very complex illustrations and furthermore
are mistakable. Instead, we generate surfaces wrapping bundles of
lines. Thereby, a more intuitive representation of different tracts is
achieved.
IEEE
2005
Conference-Paper
http://edoc.mpg.de/279027
urn:ISBN:0-7803-9462-3
IEEE Visualization 2005 (VIS 2005), IEEE, 51-58 (2005)
en
oai:edoc.mpg.de:2790552012-09-1987:934
Bayesian Relighting
Fuchs, Martin
Blanz, Volker
Seidel, Hans-Peter
Deussen, Oliver
Keller, Alexander
Bala, Kavita
Dutré, Philip
Fellner, Dieter W.
Spencer, Stephen N.
We present a simple method for relighting real objects viewed from a
fixed camera position. Instead of setting up a calibrated
measurement device, such as a light stage, we manually sweep a spotlight
over the walls of a white room, illuminating the object indirectly.
In contrast
to previous methods, we use arbitrary and unknown angular distributions of
incoming light. Neither the incident light nor the reflectance function
need to be represented explicitly in our approach.\\
%
The new method relies on images of a probe object, for instance a black
snooker ball, placed near the target object. Pictures of the probe in a novel
illumination are decomposed into a linear combination of measured images of
the probe. Then, a linear combination of images of the target object with the
same coefficients produces a synthetic image with the new illumination. We
use a simple Bayesian approach to find the most plausible output image, given
the picture of the probe and the statistics
observed in the dataset of samples.\\
%
Our results for a variety of novel illuminations, including synthetic lighting
by relatively narrow light sources as well as natural illuminations,
demonstrate that the new technique is a
useful, low cost alternative to existing techniques for a broad range of
objects and materials.
Eurographics Association
(c) The Eurographics Association 2005
2005
Conference-Paper
http://edoc.mpg.de/279055
urn:ISBN:3-905673-23-1
Rendering Techniques 2005: Eurographics Symposium on Rendering, Eurographics Association, 157-164 (2005)
en
oai:edoc.mpg.de:3143722012-09-1987:934
Towards Stable and Salient Multi-View Representation of 3D Shapes
Yamauchi, Hitoshi
Saleem, Waqar
Yoshizawa, Shin
Karni, Zachi
Belyaev, Alexander
Seidel, Hans-Peter
Spagnuolo, M.
Belyaev, A.
Suzuki, H.
An approach to automatically select stable and salient representative views of
a given 3D object is proposed. Initially, a set of viewpoints are uniformly
sampled from the surface of a bounding sphere. The sampled viewpoints are
connected to their closest points to form a spherical graph in which each edge
is weighted by a similarity measure between the two views from its incident
vertices. Partitions of similar views are obtained using a graph partitioning
procedure and their ``centroids'' are considered to be their representative
views. Finally, the views are ranked based on a saliency measure to form the
object's representative views. This leads to a compact, human-oriented 2D
description of a 3D object, and as such, is useful both for traditional
applications like presentation and analysis of 3D
shapes, and for emerging ones like indexing and retrieval in large shape
repositories.
IEEE
2006
Conference-Paper
http://edoc.mpg.de/314372
urn:ISBN:0-7695-2591-1
IEEE International Conference on Shape Modeling and Applications 2006 (SMI 2006), IEEE, 265-270 (2006)
en
oai:edoc.mpg.de:3143742012-09-1987:934
Curvilinear Spherical Parameterization
Zayer, Rhaleb
Rössl, Christian
Seidel, Hans-Peter
We present an efficient approach for solving the spherical parameterization
problem. The essence of the approach is to look for a solution in the
curvilinear coordinate system, without requiring the additional spherical
constraints usually needed in cartesian formulations. This setup allows us to
take full advantage of some existing techniques originally developed for planar
parameterization. Our results substantiate the efficiency of the method and
confirm its robustness. Meshes of non-trivial geometry with tens of thousands
of triangles are processed in a few seconds, always yielding bijective maps.
This computational achievement bridges a so far wide gap in performance between
spherical and planar parameterization.
IEEE
2006
Conference-Paper
http://edoc.mpg.de/314374
urn:ISBN:0-7695-2591-1
Shape Modeling International (SMI), IEEE, 57-64 (2006)
en
oai:edoc.mpg.de:3143822012-09-1987:934
A Perceptual Framework for Contrast Processing of High Dynamic Range Images
Mantiuk, Rafał
Myszkowski, Karol
Seidel, Hans-Peter
Image processing often involves an image transformation into a
domain that is better correlated with visual perception, such as the
wavelet domain, image pyramids, multi-scale contrast
representations, contrast in retinex algorithms, and chroma,
lightness and colorfulness predictors in color appearance models.
Many of these transformations are not ideally suited for image
processing that significantly modifies an image. For example, the
modification of a single band in a multi-scale model leads to an
unrealistic image with severe halo artifacts. Inspired by gradient
domain methods we derive a framework that imposes constraints on the
entire set of contrasts in an image for a full range of spatial
frequencies. This way, even severe image modifications do not
reverse the polarity of contrast. The strengths of the framework are
demonstrated by aggressive contrast enhancement and a visually
appealing tone mapping which does not introduce artifacts.
Additionally, we perceptually linearize contrast magnitudes using a
custom transducer function. The transducer function has been derived
especially for the purpose of HDR images, based on the contrast
discrimination measurements for high contrast stimuli.
2006
Article
http://edoc.mpg.de/314382
ACM Transactions on Applied Perception, v.3, 286-308 (2006)
en
oai:edoc.mpg.de:3143852012-09-1987:934
BSP Shapes
Stoll, Carsten
Seidel, Hans-Peter
Alexa, Marc
We discuss a shape representation based on a set of disconnected
(planar) polygons. The polygons are computed
by creating a BSP that contains approximately linear surface
patches in each cell. This is achieved by employing two
heuristics for finding appropriate split planes in each cell.
Leaf nodes in the BSP tree represent either polygonal surface
approximations or empty (clip) cells rather than split
planes. We show that the resulting set of disconnected primitives
typically leads to a better two-sided Hausdorff error
for a given number of primitives than meshes. The BSP
cells can be coded with few bits and, consequently, the tree
is a compact shape representation. The special properties
of BSPs are very useful in applications that need to perform
spatial queries on the primitives, such as for occlusion and
view frustum culling, and proximity or collision tests.
IEEE
2006
Conference-Paper
http://edoc.mpg.de/314385
urn:ISBN:0-7695-2591-1
2006 International Conference on Shape Modeling and Applications (SMI 2006), IEEE, 42-47 (2006)
en
oai:edoc.mpg.de:3143942012-09-1987:934
Feature-preserving Denoising of Time-varying Range Data
Schall, Oliver
Belyaev, Alexander
Seidel, Hans-Peter
Pfister, Hanspeter
We present a technique for accurate denoising of time-varying
range data. It is inspired by the idea of similarity-based
non-local image filtering and spatio-temporal bilateral filtering
for video processing. We build upon both ideas and are to our
knowledge the first method which extends them to time-varying
geometric data. Our proposed algorithm is easy to implement,
preserves fine shape features and produces an accurate and
homogeneous smoothing result in the spatial and along the time
domains.
ACM
2006
Conference-Paper
http://edoc.mpg.de/314394
urn:ISBN:1-59593-364-6
SIGGRAPH 2006 Sketches and Applications, ACM (2006)
en
oai:edoc.mpg.de:3144382012-09-1987:934
Distributed Rendering for Multiview Parallax Displays
Annen, Thomas
Matusik, Wojciech
Zwicker, Matthias
Pfister, Hanspeter
Seidel, Hans-Peter
Woods, Andrew J.
Dodgson, Neil A.
Merritt, John O.
Bolas, Mark T.
McDowall, Ian E.
3D display technology holds great promise for the future of television, virtual
reality, entertainment, and visualization.
Multiview parallax displays deliver stereoscopic views without glasses to
arbitrary positions within the
viewing zone. These systems must include a high-performance and scalable 3D
rendering subsystem in order
to generate multiple views at real-time frame rates. This paper describes a
distributed rendering system for
large-scale multiview parallax displays built with a network of PCs, commodity
graphics accelerators, multiple
projectors, and multiview screens. The main challenge is to render various
perspective views of the scene and
assign rendering tasks effectively. In this paper we investigate two different
approaches: Optical multiplexing for
lenticular screens and software multiplexing for parallax-barrier displays. We
describe the construction of largescale
multi-projector 3D display systems using lenticular and parallax-barrier
technology. We have developed
different distributed rendering algorithms using the Chromium stream-processing
framework and evaluate the
trade-offs and performance bottlenecks. Our results show that Chromium is well
suited for interactive rendering
on multiview parallax displays.
SPIE
2006
Conference-Paper
http://edoc.mpg.de/314438
urn:ISBN:0-8194-6095-8
Proceedings of Stereoscopic Displays and Virtual Reality Systems XIII, SPIE, 231-240 (2006)
en
oai:edoc.mpg.de:3144472012-09-1987:934
Dynamic Remeshing and Applications
Vorsatz, Jens
Universität des Saarlandes
2006
PhD-Thesis
http://edoc.mpg.de/314447
en
oai:edoc.mpg.de:3144622012-09-1987:934
Analysis of Reproducing Real-World Appearance on Displays of Varying Dynamic Range
Yoshida, Akiko
Mantiuk, Rafał
Myszkowski, Karol
Seidel, Hans-Peter
We conduct a series of experiments to investigate the desired properties of a
tone mapping operator (TMO) and to design such an operator based on subjective
data. We propose a novel approach to the tone mapping problem, in which the
tone mapping parameters are determined based on the data from subjective
experiments, rather than an image processing algorithm or a visual model. To
collect this data, a series of experiments are conducted in which the subjects
adjust three generic TMO parameters: brightness, contrast and color saturation.
In two experiments, the subjects are to find a) the most preferred image
without a reference image (preference task) and b) the closest image to the
real-world scene which the subjects are confronted with (fidelity task). We
analyze subjects' choice of parameters to provide more intuitive control over
the parameters of a tone mapping operator. Unlike most of the researched TMOs
that focus on rendering for standard low dynamic range monitors, we consider a
broad range of potential displays, each offering different dynamic range and
brightness. We simulate capabilities of such displays on a high dynamic range
(HDR) display. This allows us to address the question of how tone mapping needs
to be adjusted to accommodate displays with drastically different dynamic
ranges.
2006
Article
http://edoc.mpg.de/314462
urn:ISSN:0167-7055
Computer Graphics Forum, v.25, 415-426 (2006)
en
oai:edoc.mpg.de:3144662012-09-1987:934
Geometric Modeling Based on Triangle Meshes
Botsch, Mario
Pauly, Mark
Rössl, Christian
Bischoff, Stephan
Kobbelt, Leif
In the last years triangle meshes have become increasingly popular and are nowad
ays intensively used in many different areas of computer graphics and geometry p
rocessing. In classical CAGD irregular triangle meshes developed into a valuable
alternative to traditional spline surfaces, since their conceptual simplicity a
llows for more flexible and highly efficient processing. This course discusses
the whole geometry processing pipeline based on triangle meshes.
ACM
2006
Conference-Paper
http://edoc.mpg.de/314466
SIGGRAPH Course Notes, ACM (2006)
en
oai:edoc.mpg.de:3144782012-09-1987:934
Efficient Global Illumination for Dynamic Scenes
Tawara, Takehiro
Universität des Saarlandes
2006
PhD-Thesis
http://edoc.mpg.de/314478
en
oai:edoc.mpg.de:3144812012-09-1987:934
Physically Based Tracking of Cloth
Hasler, Nils
Asbach, Mark
Rosenhahn, Bodo
Ohm, Jens-Rainer
Seidel, Hans-Peter
Kobbelt, Leif
Kuhlen, Torsten
Aach, Til
Westermann, Rüdiger
In this work a method for tracking fabrics in videos is proposed which, unlike
most other cloth tracking algorithms,
employs an analysis-by-synthesis approach. That is tracking consists of
optimising a set of parameters of a mass-sp
ring model that is used to simulate the textile, defining on the one hand the
fabric properties and on the other the
positions of a limited number of constrained points of the simulated cloth. To
improve the tracking accuracy and to
overcome the inherently chaotic behaviour of the real fabric several methods
to track features on the cloth's surfa
ce and the best way to influence the simulation are evaluated.
IOS
2006
Conference-Paper
http://edoc.mpg.de/314481
urn:ISBN:1-58603-688-2
11th International Fall Workshop on Vision, Modeling, and Visualization 2006 ({VMV} 2006), IOS, 49-56 (2006)
en
oai:edoc.mpg.de:3144982012-09-1987:934
Multifield-Graphs: An Approach to Visualizing Correlations in Multifield Scalar Data
Sauber, Natascha
Theisel, Holger
Seidel, Hans-Peter
Gröller, Eduard
Pang, Alex
Silva, Claudio T.
Stasko, John
van Wijk, Jarke
We present an approach to visualizing
correlations in 3D multifield scalar data.
The core of our approach is the computation of correlation fields, which are
scalar fields
containing the local correlations of
subsets of the multiple fields.
While the visualization of the correlation fields can be done using
standard 3D volume visualization techniques, their huge number makes selection
and
handling a challenge.
We introduce the Multifield-Graph to give an overview of which multiple fields
correlate and to show the strength of their correlation. This information
guides the selection of informative correlation fields for visualization.
We use our approach to visually analyze a number of real and
synthetic multifield datasets.
IEEE
2006
Conference-Paper
http://edoc.mpg.de/314498
urn:ISSN:1077-2626
IEEE Visualization Conference 2006, IEEE, 917-924 (2006)
en
oai:edoc.mpg.de:3145142012-09-1987:934
Computational Differential Geometry Tools for Surface Interrogation, Fairing, and Design
Yoshizawa, Shin
Universität des Saarlandes
2006
PhD-Thesis
http://edoc.mpg.de/314514
en
oai:edoc.mpg.de:3145242012-09-1987:934
Learning-Based Facial Rearticulation Using Streams of 3D Scans
Bargmann, Robert
Blanz, Volker
Seidel, Hans-Peter
Chen, Bing-Yu
In this paper, we present a new approach that generates synthetic mouth
articulations from an audio file and that transfers them to different face
meshes. It is based on learning articulations from a stream of 3D scans of a
real person acquired by a structured light scanner at 40 three-dimensional
frames per second. Correspondence between these scans over several speech
sequences is established via optical flow. We propose a novel type of Principal
Component Analysis that considers variances only in a sub-region of the face,
while retaining the full dimensionality of the original vector space of sample
scans. Audio is recorded at the same time, so the head scans can be
synchronized with phoneme and viseme information for computing viseme clusters.
Given a new audio sequence along with text data, we are able to quickly create
in a fully automated fashion an animation synchronized with that new sentence
by morphing between the visemes along a path in viseme-space. The methods
described in the paper include an automated process for data analysis in
streams of 3D scans, and a framework that connects the system to existing
static face modeling technology for articulation transfer.
National Taiwan University
2006
Conference-Paper
http://edoc.mpg.de/314524
The 14th Pacific Conference on Computer Graphics and Applications, National Taiwan University, 232-241 (2006)
en
oai:edoc.mpg.de:3145352012-09-1987:934
Geometric Modeling Based on Triangle Meshes
Botsch, Mario
Pauly, Mark
Rössl, Christian
Bischoff, Stephan
Kobbelt, Leif
In the last years triangle meshes have become increasingly popular and are nowad
ays intensively used in many different areas of computer graphics and geometry p
rocessing. In classical CAGD irregular triangle meshes developed into a valuable
alternative to traditional spline surfaces, since their conceptual simplicity a
llows for more flexible and highly efficient processing. This course discusses
the whole geometry processing pipeline based on triangle meshes.
Eurographics
2006
Conference-Paper
http://edoc.mpg.de/314535
Eurographics Tutorial Notes, Eurographics (2006)
en
oai:edoc.mpg.de:3145432012-09-1987:934
Incremental Raycasting of Piecewise Quadratic Surfaces on the GPU
Stoll, Carsten
Gumhold, Stefan
Seidel, Hans-Peter
Wald, Ingo
Parke, Steven G.
To overcome the limitations of triangle and point based surfaces
several authors have recently investigated surface representations
that are based on higher order primitives. Among these are
MPU, SLIM surfaces, dynamic skin surfaces and higher order isosurfaces.
Up to now these representations were not suitable for
interactive applications because of the lack of an efficient rendering
algorithm.
In this paper we close this gap for implicit surface representations
of degree two by developing highly optimized GPU implementations
of the raycasting algorithm. We investigate techniques
for fast incremental raycasting and cover per fragment and per
quadric backface culling. We apply the approaches to the rendering
of SLIM surfaces, quadratic iso-surfaces over tetrahedral meshes
and bilinear quadrilaterals. Compared to triangle based surface approximations
of similar geometric error we achieve only slightly
lower frame rates but with much higher visual quality due to the
quadratic approximation power of the underlying surfaces.
IEEE
2006
Conference-Paper
http://edoc.mpg.de/314543
urn:ISBN:1-4244-0693-5
IEEE Symposium on Interactive Raytracing 2006 Proceedings, IEEE, 141-150 (2006)
en
oai:edoc.mpg.de:3146112012-09-1987:934
Geodesics Guided Constrained Texture Deformation
Stoll, Carsten
Karni, Zachi
Seidel, Hans-Peter
We present a method that deforms an image plane to visually meet the shape and
pose of a manifold sur-face. The user provides constraints that couple a small
number of surface points with their corresponding im-age pixels to initially
deform the plane. Matching, based on geodesic distances, couples additional
points, followed by a second deformation that brings the im-age plane into its
final pose and shape. The method works on any type of surface that supports
geodesic distances evaluation. This includes not-triangulated and high genus
models with arbitrary topology. The result is a smooth, visually pleasing and
realistic tex-tured surface that can be superimposed onto or used instead of
the original model and with some limitations can be considered as a
parameterization or remeshing method for the area of interest.
National Taiwan University Press
2006
Conference-Paper
http://edoc.mpg.de/314611
The 14th Pacific Conference on Computer Graphics and Applications Proceedings, National Taiwan University Press, 144-152 (2006)
en
oai:edoc.mpg.de:3146122012-09-1987:934
Mesostructure from Specularity
Chen, Tongbo
Goesele, Michael
Seidel, Hans-Peter
We describe a simple and robust method for surface
mesostructure acquisition. Our method builds on the observation
that specular reflection is a reliable visual cue
for surface mesostructure perception. In contrast to most
photometric stereo methods, which take specularities as
outliers and discard them, we propose a progressive acquisition
system that captures a dense specularity field as
the only information for mesostructure reconstruction. Our
method can efficiently recover surfaces with fine-scale geometric
details from complex real-world objects with a wide
variety of reflection properties, including translucent, low
albedo, and highly specular objects. We show results for a
variety of objects including human skin, dried apricot, orange,
jelly candy, black leather and dark chocolate.
IEEE
2006
Conference-Paper
http://edoc.mpg.de/314612
urn:ISBN:0-7695-2597-0
2006 IEEE Computer Society Conference on Computer Vision and Pattern Recognition (CVPR 2006), IEEE, 1825-1832 (2006)
en
oai:edoc.mpg.de:3146432012-09-1987:934
Statistical Learning for Shape Applications
Saleem, Waqar
Wang, Danyi
Belyaev, Alexander
Seidel, Hans-Peter
Statistical methods are well suited to the large amounts of data typically
involved in digital shape applications. In this paper, we look at two
statistical learning methods related to digital shape processing. The first,
\textit{neural meshes}, learns the shape of a given point cloud \--- the
surface reconstruction problem \--- in $O(n^2)$ time. We present an alternate
implementation of the algorithm that takes $O(n\log n)$ time. Secondly, we
present a simple method to automatically learn the correct orientation of a
shape in an image from a database of images with correctly oriented shapes.
CNR
2006
Conference-Paper
http://edoc.mpg.de/314643
1st International Symposium on Shapes and Semantics, CNR, 53-60 (2006)
en
oai:edoc.mpg.de:3146442012-09-1987:934
High-Fidelity Imaging - The Computational Models of the Human Visual System in High Dynamic Range Video Video Compression, Visible Difference Prediction and Image Processing
Mantiuk, Rafał
Universität des Saarlandes
2006
PhD-Thesis
http://edoc.mpg.de/314644
en
oai:edoc.mpg.de:3146542012-09-1987:934
Adaptive Fourier-Based Surface Reconstruction
Schall, Oliver
Belyaev, Alexander
Seidel, Hans-Peter
Kim, Myung-Soo
Shimada, Kenji
In this paper, we combine Kazhdan's FFT-based approach to
surface reconstruction from oriented points with adaptive
subdivision and partition of unity blending techniques. The
advantages of our surface reconstruction method include a more
robust surface restoration in regions where the surface bends
close to itself and a lower memory consumption. The latter allows
us to achieve a higher reconstruction accuracy than the original
global approach. Furthermore, our reconstruction process is
guided by a global error control achieved by computing the
Hausdorff distance of selected input samples to intermediate
reconstructions.
Springer
2006
Conference-Paper
http://edoc.mpg.de/314654
urn:ISBN:3-540-36711-X
Geometric modeling and processing - GMP 2006 : 4th International Conference, Springer, 34-44 (2006)
en
oai:edoc.mpg.de:3564922012-09-1987:934
Combining Proof Producing Decision Procedures
Ranise, Silvio
Ringeissen, Christophe
Tran, Duc-Khanh
Springer
2007
Conference-Paper
http://edoc.mpg.de/356492
urn:ISBN:978-3-540-74620-1
info:doi/10.1007/978-3-540-74621-8_16
Wolter, Frank: Frontiers of Combining Systems : 6th International Symposium, FroCoS 2007, Springer, 237-251 (2007)
en
oai:edoc.mpg.de:3564932012-09-1987:934
Implicit Boundary Control of Vector Field Based Shape Deformations
von Funck, Wolfram
Theisel, Holger
Seidel, Hans-Peter
We present a shape deformation approach which preserves
volume, prevents self-intersections and allows for exact control of the
deformation impact. The volume preservation and prevention of selfintersections
are achieved by utilizing the method of Vector Field Based
Shape Deformations. This method produces physically plausible deformations
efficiently by integrating formally constructed divergence-free
vector fields, where the region of influence is described by implicitly
defined shapes. We introduce an implicit representation of deformation
boundaries, which allows for an exact control of the deformation: By
placing the boundaries directly on the shape surface, the user can specify
precisely where the shape should be deformed and where not. The simple
polygonal representation of the boundaries allows for a GPU implementation,
which is able to deform high-resolution meshes in real-time.
Springer
2007
Conference-Paper
http://edoc.mpg.de/356493
urn:ISBN:3-540-73842-8
info:doi/10.1007/978-3-540-73843-5_10
Martin, Ralph; Sabin, Malcolm; Winkler, Joab: Mathematics of Surfaces XII : 12th IMA International Conference, Springer, 154-165 (2007)
en
oai:edoc.mpg.de:3565012012-09-1987:934
Automatic Decidability and Combinability Revisited
Lynch, Christopher
Tran, Duc-Khanh
Springer
2007
Conference-Paper
http://edoc.mpg.de/356501
urn:ISBN:978-3-540-73594-6
info:doi/10.1007/978-3-540-73595-3_22
Pfenning, Frank: Automated Deduction – CADE-21 : 21st International Conference on Automated Deduction, Springer, 328-344 (2007)
en
oai:edoc.mpg.de:3565022012-09-1987:934
Global Illumination using Photon Ray Splatting
Herzog, Robert
Havran, Vlastimil
Kinuwaki, Shinichi
Myszkowski, Karol
Seidel, Hans-Peter
We present a novel framework for efficiently computing the indirect
illumination in diffuse and moderately glossy scenes using density estimation
techniques.
A vast majority of existing global illumination approaches either quickly
computes an approximate solution, which may not be adequate for previews, or
performs a much more time-consuming computation to obtain high-quality results
for the indirect illumination. Our method improves photon density estimation,
which is an approximate solution, and leads to significantly better visual
quality in particular for complex geometry, while only slightly increasing the
computation time. We perform direct splatting of photon rays, which allows us
to use simpler search data structures. Our novel lighting computation is
derived from basic radiometric theory and requires only small changes to
existing photon splatting approaches.
Since our density estimation is carried out in ray space rather than on
surfaces, as in the commonly used photon mapping algorithm, the results are
more robust against geometrically incurred sources of bias. This holds also in
combination with final gathering where photon mapping often overestimates the
illumination near concave geometric features. In addition, we show that our
splatting technique can be extended to handle moderately glossy surfaces and
can be combined with traditional irradiance caching for sparse sampling and
filtering in image space.
Max-Planck-Institut für Informatik
2007
Report
http://edoc.mpg.de/356502
en
oai:edoc.mpg.de:3565032012-09-1987:934
3D Reconstruction of Emission and Absorption in Planetary Nebulae
Lintu, Andrei
Lensch, Hendrik P. A.
Magnor, Marcus
El-Abed, Sasha
Seidel, Hans-Peter
This paper addresses the problem of reconstructing the 3D structure of
planetary nebulae from 2D observations. Assuming axial symmetry, our method
jointly reconstructs the distribution of dust and ionized gas in the nebulae
from observations at two different wavelengths. In an inverse rendering
framework we optimize for the emission and absorption densities which are
correlated to the gas and dust distribution present in the nebulae. First, the
density distribution of the dust component is estimated based on an infrared
image, which traces only the dust distribution due to its intrinsic
temperature. In a second step, we optimize for the gas distribution by
comparing the rendering of the nebula to the visible wavelength image. During
this step, besides the emission of the ionized gas, we further include the
effect of absorption and scattering due to the already estimated dust
distribution. Using the same approach, we can as well start with a radio image
from which the gas distribution is derived without absorption, then deriving
the dust distribution from the visible wavelength image considering absorption
and scattering. The intermediate steps and the final reconstruction results are
visualized at real-time frame rates using a volume renderer. Using our method
we recover both gas and dust density distributions present in the nebula by
exploiting the distinct absorption or emission parameters at different
wavelengths.
Eurographics Association
2007
Conference-Paper
http://edoc.mpg.de/356503
urn:ISBN:978-1-56881-367-7
info:doi/10.2312/VG/VG07/009-016
Fellner, Dieter; Möller, Torsten; Fraser, Simon: Volume Graphics 2007 : Eurographics / IEEE VGTC Symposium Proceedings
Sixth International Symposium on Volume Graphics, Eurographics Association, 9-16 (2007)
en
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