No (1441)
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1441
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GPU-based Adaptive Surface Reconstruction for Real-time SPH Fluids
Du, Shuchen; Kanai, Takashi
2014 - English
We propose a GPU-based adaptive surface reconstruction algorithm for Smoothed-Particle Hydrodynamics (SPH)
fluids. The adaptive surface is reconstructed from 3-level grids as proposed by [Akinci13]. The novel part of
our algorithm is a pattern based approach for crack filling, which is recognized as the most challengeable part of
building adaptive surfaces. Unlike prior CPU-based approaches [Shu95, Shekhar96, Westermann99, Akinci13]
that detect and fill cracks according to some criteria during program running that were slow and unrobust, all
the possible crack patterns are analyzed and defined in advance and later, during program running, the cracks are
detected and filled according to the patterns. Our approach is thus robust, GPU-friendly, and easy to implement.
Results obtained show that our algorithm can produce surface meshes of almost the same quality as those produced
by the conventional Marching Cubes method, with significantly reduced computation time and memory usage.
Keywords:
grafické procesory; rekonstrukce povrchu; počítačová animace; simulace kapaliny; na částicích založená simulace; jemná částicová hydrodynamika; graphic processing units; surface reconstruction; computer animation; fluid simulation; particle-based simulation; smoothed particle hydrodynamics
Available in digital repository of ZČU.
GPU-based Adaptive Surface Reconstruction for Real-time SPH Fluids
We propose a GPU-based adaptive surface reconstruction algorithm for Smoothed-Particle Hydrodynamics (SPH) fluids. The adaptive surface is reconstructed from 3-level grids as proposed by [Akinci13]. ...
Image-based 3D Modelling in Archaeology: Application and Evaluation
Bernardes, Paulo; Magalhães, Fernanda; Ribeiro, Jorge; Madeira, Joaquim; Martins, Manuela
2014 - English
Image-based 3D modelling tools and techniques can be used to support some stages of the archaeological process.
Two application examples, for two sites of the Roman Era, are presented, illustrating the usage and usefulness
of such tools for the archaeological survey. For a quadrangular pool in the Milreu Roman Villa (Faro, Portugal),
the 3D models resulting from the application of two different image-based modelling tools, using the same initial
set of digital photos, are compared regarding time spent and model accuracy. For the Fonte do Ídolo in Bracara
Augusta (Braga, Portugal), the result of a traditional survey is compared both with a laser-based survey and an
image-based survey.
Keywords:
modelování založené na obrazech; 3D modelování; archeologie; image-based modelling; 3D modelling; archaeology
Available in digital repository of ZČU.
Image-based 3D Modelling in Archaeology: Application and Evaluation
Image-based 3D modelling tools and techniques can be used to support some stages of the archaeological process. Two application examples, for two sites of the Roman Era, are presented, illustrating ...
A Physically-based Simulation of a Caenorhabditis elegans
Mujika, Andoni; de Mauro, Alessandro; Robin, Gautier; Epelde, Gorka; Oyarzun, David
2014 - English
This paper shows the three-dimensional physical model created to simulate the locomotion of the Caenorhabditis
elegans. The C. elegans is a very deep studied nematode as it is considered one of the simplest nervous systems in
nature, made of 302 neurons and about 8000 connections. To date, there is no system that can faithfully reproduce
the rich behavioral repertoire of this tiny worm in terms of neural activity and locomotion. The Si Elegans project
aims to develop the first hardware-based computing framework that will accurately mimic a C. elegans worm in
real time. It will enable complex and realistic behavior to emerge through interaction with a rich and dynamic
simulation of a natural or laboratory environment. As a result, the locomotion of the virtual worm will be rendered
in a web-based platform. In this paper, we describe the approach followed for the physically-based modeling and
simulation of C. elegans and the benefits of our approach compared to existing ones. The main contribution of our
work is the utilization of biphasic springs in the structure that represents the worm in the virtual environment and
a Finite Element Method based internal force field to simulate the internal pressure of the body.
Keywords:
fyzikální modelování; 3D graphics; biologické simulace; háďátko obecné; physically-based modelling; 3D grafika; biological simulations; caenorhabditis elegans
Available in digital repository of ZČU.
A Physically-based Simulation of a Caenorhabditis elegans
This paper shows the three-dimensional physical model created to simulate the locomotion of the Caenorhabditis elegans. The C. elegans is a very deep studied nematode as it is considered one of the ...
A method of micro facial expression recognition based on dense facial motion data
Akagi, Yasuhiro; Kawasaki, Hiroshi
2014 - English
In this paper, we propose a method for recognizing a micro expression which is a small motion appearing on a
face by using a high density and high frame-rate 3D reconstruction method. Some studies report that the micro
expressions are caused by the change of mental state. If we can recognize the micro expressions, this information
could be useful for machines to understand the mental state of a human. With advancements of 3D reconstruction
methods, methods have been proposed to reconstruct dynamic objects such as motions of a human’s body in high
accuracy with high frame rate. Based on the data obtained from the high quality shape reconstruction method, the
proposed method recognizes the micro expressions. To detect a part of the face where the micro-expressions are
appeared, we propose an experimental estimation of the part. We also report a recognition rate of the change of
the mental state using the experimental system.
Keywords:
rozpoznávání obrazu; výraz obličeje; pohyby v obličeji; image recognition; facial expression; facial motion
Available in digital repository of ZČU.
A method of micro facial expression recognition based on dense facial motion data
In this paper, we propose a method for recognizing a micro expression which is a small motion appearing on a face by using a high density and high frame-rate 3D reconstruction method. Some studies ...
Spatter Tracking in Laser- and Manual Arc Welding with Sensor-level Pre-processing
Lahdenoja, Olli; Säntti, Tero; Laiho, Mika; Poikonen, Jonne
2014 - English
This paper presents methods for automated visual tracking of spatters in laser- and manual arc welding. Imaging
of the welding process is challenging due to extreme conditions of high radiated light intensity variation. The
formation and the number of spatters ejected in the welding process are dependent on the parameters of the
welding process, and can potentially be used to tune the process towards better quality (either on-line of offline).
In our case, the spatter segmentation is based either on test on object elongatedness or Hough transform,
which are applied on pre-processed image sequences captured by a high-speed smart camera. Part of the
segmentation process (adaptive image capture and edge extraction) is performed on the camera, while the other
parts of the algorithm are performed off-line in Matlab. However, our intention is to move the computation
towards the camera or an attached FPGA.
Keywords:
vizuální trasování; laserové svařování; obloukové svařování; chytrá kamera; visual tracking; laser welding; arc welding; smart camera
Available in digital repository of ZČU.
Spatter Tracking in Laser- and Manual Arc Welding with Sensor-level Pre-processing
This paper presents methods for automated visual tracking of spatters in laser- and manual arc welding. Imaging of the welding process is challenging due to extreme conditions of high radiated light ...
Ocean wave simulation by the mix of FFT and Perlin Noise
Tian, Li
2014 - English
For the application of ocean wave, a new height-field simulation method is proposed by the mix of FFT and
Perlin Noise, and OpenSceneGraph (OSG) and VC++ 2008 are used to simulate realistic ocean wave. The
method takes wind effects into consideration, and uses Philips model and Gauss random numbers to produce
ocean wave spectrum, which is then transformed to wave height-field by FFT. Perlin Noise is overlaid to disturb
the wave height to generate a vivid and random sea surface. Simulation results show the effectiveness of the
proposed method.
Keywords:
oceánské vlnové spektrum; rychlá Fourierova transformace; Perlinův šum; počítačová simulace; graf otevřené scény; ocean wave spectrum; fast Fourier transform; Perlin noise; computer simulation; OpenSceneGraph
Available in digital repository of ZČU.
Ocean wave simulation by the mix of FFT and Perlin Noise
For the application of ocean wave, a new height-field simulation method is proposed by the mix of FFT and Perlin Noise, and OpenSceneGraph (OSG) and VC++ 2008 are used to simulate realistic ocean ...
Fast and Robust Tessellation-Based Silhouette Shadows
Milet, Tomáš; Kobrtek, Jozef; Zemčík, Pavel; Pečiva, Jan
2014 - English
This paper presents a new simple, fast and robust approach in computation of per-sample precise shadows. The
method uses tessellation shaders for computation of silhouettes on arbitrary triangle soup. We were able to reach
robustness by our previously published algorithm using deterministic shadow volume computation. We also propose
a new simplification of the silhouette computation by introducing reference edge testing. Our new method
was compared with other methods and evaluated on multiple hardware platforms and different scenes, providing
better performance than current state-of-the art algorithms. Finally, conclusions are drawn and the future work is
outlined.
Keywords:
stíny; siluety; teselační shadery; výpočet objemu stínu; shadows; silhouettes; tessellation shaders; shadow volume computation
Available in digital repository of ZČU.
Fast and Robust Tessellation-Based Silhouette Shadows
This paper presents a new simple, fast and robust approach in computation of per-sample precise shadows. The method uses tessellation shaders for computation of silhouettes on arbitrary triangle soup. ...
Human-Computer Interaction Using Robust Gesture Recognition
Endler, Matthias; Lobachev, Oleg; Guthe, Michael
2014 - English
We present a detector cascade for robust real-time tracking of hand movements on consumer-level hardware. We
adapt existing detectors to our setting: Haar, CAMSHIFT, shape detector, skin detector. We use all these detectors
at once. Our main contributions are: first, utilization of bootstrapping: Haar bootstraps itself, then its results are
used to bootstrap the other filters; second, the usage of temporal filtering for more robust detection and to remove
outliers; third, we adapted the detectors for more robust hand detection. The resulting system produces very robust
results in real time. We evaluate both the robustness and the real-time capability.
Keywords:
interakce člověk-počítač; rozpoznávání gest; počítačové vidění; sledování rukou; human computer interaction; gesture recognition; computer vision; hand tracking
Available in digital repository of ZČU.
Human-Computer Interaction Using Robust Gesture Recognition
We present a detector cascade for robust real-time tracking of hand movements on consumer-level hardware. We adapt existing detectors to our setting: Haar, CAMSHIFT, shape detector, skin detector. We ...
Particle systems-based riverbed modelling over a terrain with hardness layer
Warszawski, Korneliusz; Niekel, Slawomir
2014 - English
This paper proposes a method that applies particle systems to simulate results of hydrological erosion caused by
spout, like riverbeds. The terrain model is divided into two layers. The first one stores heights data (typical heightfield)
while the second is reserved for hardness data. This data structure enables fast and simple implementation
of terrain deformation. We present the construction of a particle system terrain modifier, its main attributes and
how they influence the final product of the modelling process. The proposed technique behaves like in classical
particle systems. It uses emitter as element that control starting location, direction and quantity of particles in
a given simulation environment. We choose parameters for particles such as: the current position, directional
angle, linear velocity, rotation angle, rotation velocity and the size which define its zone of influence for landscape
modification processes. Each emitted particle is moving (rolling) over the surface of terrain structure making
deformations at its current position. Scale of the modifications depends on particle parameters and landscape
structure susceptibility for modifications process under the particle influence zone. The proposed method is not
intended to simulate physically erosion process, but focuses on its results for exploitation in virtual environments
in real-time simulations and rapid prototyping of virtual terrains.
Keywords:
částicové systémy; terénní povrchové modelování; říční břehy; virtuální prostředí; hydrologická eroze; particle systems; terrain surface modelling; riverbeds; virtual environments; hydrological erosion
Available in digital repository of ZČU.
Particle systems-based riverbed modelling over a terrain with hardness layer
This paper proposes a method that applies particle systems to simulate results of hydrological erosion caused by spout, like riverbeds. The terrain model is divided into two layers. The first one ...
Inter-annotator agreement on spontaneous czech language
Valenta, Tomáš; Šmídl, Luboš; Švec, Jan
2014 - English
Keywords:
automatické rozpoznávání řeči; IAA; automatic speech recognition; IAA
Available in the ZČU Library.
Inter-annotator agreement on spontaneous czech language
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