32-Issue 7

Permanent URI for this collection

https://diglib7.eg.org/handle/10.2312/185
Pacific Graphics Proceedings

BibTeX (32-Issue 7)
                
@article{
10.1111:cgf.12206,

journal = {Computer Graphics Forum},
title = {{
Dynamic Comics for Hierarchical Abstraction of 3D Animation Data}},

author = {
Choi, Myung Geol
 and 
Noh, Seung-Tak
 and 
Komura, Taku
 and 
Igarashi, Takeo
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12206}

}
                
@article{
10.1111:cgf.12207,

journal = {Computer Graphics Forum},
title = {{
Ontology-based Model for Chinese Calligraphy Synthesis}},

author = {
Xia, Yang
 and 
Wu, Jiangqin
 and 
Gao, Pengcheng
 and 
Lin, Yuan
 and 
Mao, Tianjiao
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12207}

}
                
@article{
10.1111:cgf.12208,

journal = {Computer Graphics Forum},
title = {{
A GPU-based Streaming Algorithm for High-Resolution Cloth Simulation}},

author = {
Tang, Min
 and 
Tong, Ruofeng
 and 
Narain, Rahul
 and 
Meng, Chang
 and 
Manocha, Dinesh
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12208}

}
                
@article{
10.1111:cgf.12209,

journal = {Computer Graphics Forum},
title = {{
Constrainable Multigrid for Cloth}},

author = {
Jeon, Inyong
 and 
Choi, Kwang-Jin
 and 
Kim, Tae-Yong
 and 
Choi, Bong-Ouk
 and 
Ko, Hyeong-Seok
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12209}

}
                
@article{
10.1111:cgf.12211,

journal = {Computer Graphics Forum},
title = {{
Interactive Learning for Point-Cloud Motion Segmentation}},

author = {
Sofer, Yerry
 and 
Hassner, Tal
 and 
Sharf, Andrei
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12211}

}
                
@article{
10.1111:cgf.12210,

journal = {Computer Graphics Forum},
title = {{
Synthesizing Two-character Interactions by Merging Captured Interaction Samples with their Spacetime Relationships}},

author = {
Chan, Jacky C. P.
 and 
Tang, Jeff K. T.
 and 
Leung, Howard
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12210}

}
                
@article{
10.1111:cgf.12213,

journal = {Computer Graphics Forum},
title = {{
Stroke-guided Image Synthesis for Skeletal Structure Editing}},

author = {
Luo, Sheng-Jie
 and 
Lin, Chin-Yu
 and 
Shen, I-Chao
 and 
Chen, Bing-Yu
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12213}

}
                
@article{
10.1111:cgf.12212,

journal = {Computer Graphics Forum},
title = {{
Topology Aware Data-Driven Inverse Kinematics}},

author = {
Ho, Edmond S. L.
 and 
Shum, Hubert P. H.
 and 
Cheung, Yiu-ming
 and 
Yuen, P. C.
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12212}

}
                
@article{
10.1111:cgf.12214,

journal = {Computer Graphics Forum},
title = {{
Hair Interpolation for Portrait Morphing}},

author = {
Weng, Yanlin
 and 
Wang, Lvdi
 and 
Li, Xiao
 and 
Chai, Menglei
 and 
Zhou, Kun
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12214}

}
                
@article{
10.1111:cgf.12215,

journal = {Computer Graphics Forum},
title = {{
Garment Modeling from a Single Image}},

author = {
Zhou, Bin
 and 
Chen, Xiaowu
 and 
Fu, Qiang
 and 
Guo, Kan
 and 
Tan, Ping
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12215}

}
                
@article{
10.1111:cgf.12216,

journal = {Computer Graphics Forum},
title = {{
Fast Image-Based Modeling of Astronomical Nebulae}},

author = {
Wenger, Stephan
 and 
Lorenz, Dirk
 and 
Magnor, Marcus
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12216}

}
                
@article{
10.1111:cgf.12217,

journal = {Computer Graphics Forum},
title = {{
Lighting Simulation of Augmented Outdoor Scene Based on a Legacy Photograph}},

author = {
Xing, Guanyu
 and 
Zhou, Xuehong
 and 
Peng, Qunsheng
 and 
Liu, Yanli
 and 
Qin, Xueying
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12217}

}
                
@article{
10.1111:cgf.12218,

journal = {Computer Graphics Forum},
title = {{
Eye-Centered Color Adaptation in Global Illumination}},

author = {
Gruson, Adrien
 and 
Ribardière, Mickael
 and 
Cozot, Remi
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12218}

}
                
@article{
10.1111:cgf.12219,

journal = {Computer Graphics Forum},
title = {{
Robust Denoising using Feature and Color Information}},

author = {
Rousselle, Fabrice
 and 
Manzi, Marco
 and 
Zwicker, Matthias
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12219}

}
                
@article{
10.1111:cgf.12221,

journal = {Computer Graphics Forum},
title = {{
Artistic QR Code Embellishment}},

author = {
Lin, Yi-Shan
 and 
Luo, Sheng-Jie
 and 
Chen, Bing-Yu
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12221}

}
                
@article{
10.1111:cgf.12220,

journal = {Computer Graphics Forum},
title = {{
Second-Order Approximation for Variance Reduction in Multiple Importance Sampling}},

author = {
Lu, Heqi
 and 
Pacanowski, Romain
 and 
Granier, Xavier
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12220}

}
                
@article{
10.1111:cgf.12222,

journal = {Computer Graphics Forum},
title = {{
Interactive Physics-based Ink Splattering Art Creation}},

author = {
Lei, Su-Ian Eugene
 and 
Chen, Ying-Chieh
 and 
Chen, Hsiang-Ting
 and 
Chang, Chun-Fa
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12222}

}
                
@article{
10.1111:cgf.12223,

journal = {Computer Graphics Forum},
title = {{
Modeling by Drawing with Shadow Guidance}},

author = {
Fan, Lubin
 and 
Wang, Ruimin
 and 
Xu, Linlin
 and 
Deng, Jiansong
 and 
Liu, Ligang
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12223}

}
                
@article{
10.1111:cgf.12224,

journal = {Computer Graphics Forum},
title = {{
Soft Folding}},

author = {
Zhu, Lifeng
 and 
Igarashi, Takeo
 and 
Mitani, Jun
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12224}

}
                
@article{
10.1111:cgf.12226,

journal = {Computer Graphics Forum},
title = {{
TrayGen: Arranging Objects for Exhibition and Packaging}},

author = {
Yang, Yong-Liang
 and 
Huang, Qi-Xing
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12226}

}
                
@article{
10.1111:cgf.12225,

journal = {Computer Graphics Forum},
title = {{
Guided Real-Time Scanning of Indoor Objects}},

author = {
Kim, Young Min
 and 
Mitra, Niloy J.
 and 
Huang, Qixing
 and 
Guibas, Leonidas
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12225}

}
                
@article{
10.1111:cgf.12227,

journal = {Computer Graphics Forum},
title = {{
The POP Buffer: Rapid Progressive Clustering by Geometry Quantization}},

author = {
Limper, Max
 and 
Jung, Yvonne
 and 
Behr, Johannes
 and 
Alexa, Marc
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12227}

}
                
@article{
10.1111:cgf.12228,

journal = {Computer Graphics Forum},
title = {{
A Semi-Lagrangian Closest Point Method for Deforming Surfaces}},

author = {
Auer, Stefan
 and 
Westermann, Rüdiger
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12228}

}
                
@article{
10.1111:cgf.12229,

journal = {Computer Graphics Forum},
title = {{
Implicit Integration for Particle-based Simulation of Elasto-Plastic Solids}},

author = {
Zhou, Yahan
 and 
Lun, Zhaoliang
 and 
Kalogerakis, Evangelos
 and 
Wang, Rui
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12229}

}
                
@article{
10.1111:cgf.12230,

journal = {Computer Graphics Forum},
title = {{
Combustion Waves on the Point Set Surface}},

author = {
Jeong, SoHyeon
 and 
Kim, Chang-Hun
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12230}

}
                
@article{
10.1111:cgf.12231,

journal = {Computer Graphics Forum},
title = {{
Efficient Smoke Simulation on Curvilinear Grids}},

author = {
Azevedo, Vinicius C.
 and 
Oliveira, Manuel M.
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12231}

}
                
@article{
10.1111:cgf.12232,

journal = {Computer Graphics Forum},
title = {{
A Progressive Tri-level Segmentation Approach for Topology-Change-Aware Video Matting}},

author = {
Ju, Jinlong
 and 
Wang, Jue
 and 
Liu, Yebin
 and 
Wang, Haoqian
 and 
Dai, Qionghai
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12232}

}
                
@article{
10.1111:cgf.12233,

journal = {Computer Graphics Forum},
title = {{
Learning and Applying Color Styles From Feature Films}},

author = {
Xue, Su
 and 
Agarwala, Aseem
 and 
Dorsey, Julie
 and 
Rushmeier, Holly
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12233}

}
                
@article{
10.1111:cgf.12234,

journal = {Computer Graphics Forum},
title = {{
Multiplane Video Stabilization}},

author = {
Wang, Zhong-Qiang
 and 
Zhang, Lei
 and 
Huang, Hua
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12234}

}
                
@article{
10.1111:cgf.12235,

journal = {Computer Graphics Forum},
title = {{
Evaluation of Tone Mapping Operators for HDR-Video}},

author = {
Eilertsen, Gabriel
 and 
Wanat, Robert
 and 
Mantiuk, Rafal K.
 and 
Unger, Jonas
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12235}

}
                
@article{
10.1111:cgf.12236,

journal = {Computer Graphics Forum},
title = {{
Animated 3D Line Drawings with Temporal Coherence}},

author = {
Xu, Xiang
 and 
Seah, Hock Soon
 and 
Quah, Chee Kwang
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12236}

}
                
@article{
10.1111:cgf.12237,

journal = {Computer Graphics Forum},
title = {{
Still-Frame Simulation for Fire Effects of Images}},

author = {
Son, Minjung
 and 
Kim, Byungmoon
 and 
Wilensky, Gregg
 and 
Lee, Seungyong
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12237}

}
                
@article{
10.1111:cgf.12238,

journal = {Computer Graphics Forum},
title = {{
Boundary-Aware Extinction Mapping}},

author = {
Gautron, Pascal
 and 
Delalandre, Cyril
 and 
Marvie, Jean-Eudes
 and 
Lecocq, Pascal
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12238}

}
                
@article{
10.1111:cgf.12239,

journal = {Computer Graphics Forum},
title = {{
Adaptive Ray-bundle Tracing with Memory Usage Prediction: Efficient Global Illumination in Large Scenes}},

author = {
Tokuyoshi, Yusuke
 and 
Sekine, Takashi
 and 
Silva, Tiago da
 and 
Kanai, Takashi
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12239}

}
                
@article{
10.1111:cgf.12240,

journal = {Computer Graphics Forum},
title = {{
A Programmable Graphics Processor based on Partial Stream Rewriting}},

author = {
Middendorf, Lars
 and 
Haubelt, Christian
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12240}

}
                
@article{
10.1111:cgf.12241,

journal = {Computer Graphics Forum},
title = {{
Improving Memory Space Efficiency of Kd-tree for Real-time Ray Tracing}},

author = {
Choi, Byeongjun
 and 
Chang, Byungjoon
 and 
Ihm, Insung
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12241}

}
                
@article{
10.1111:cgf.12242,

journal = {Computer Graphics Forum},
title = {{
Level-of-Detail Streaming and Rendering using Bidirectional Sparse Virtual Texture Functions}},

author = {
Schwartz, Christopher
 and 
Ruiters, Roland
 and 
Klein, Reinhard
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12242}

}
                
@article{
10.1111:cgf.12243,

journal = {Computer Graphics Forum},
title = {{
Symmetry Robust Descriptor for Non-Rigid Surface Matching}},

author = {
Zhang, Zhiyuan
 and 
Yin, KangKang
 and 
Foong, Kelvin W. C.
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12243}

}
                
@article{
10.1111:cgf.12244,

journal = {Computer Graphics Forum},
title = {{
Polar NURBS Surface with Curvature Continuity}},

author = {
Shi, Kan-Le
 and 
Yong, Jun-Hai
 and 
Tang, Lei
 and 
Sun, Jia-Guang
 and 
Paul, Jean-Claude
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12244}

}
                
@article{
10.1111:cgf.12245,

journal = {Computer Graphics Forum},
title = {{
Coarse-to-Fine Normal Filtering for Feature-Preserving Mesh Denoising Based on Isotropic Subneighborhoods}},

author = {
Zhu, Lei
 and 
Wie, Mingqiang
 and 
Yu, Jinze
 and 
Wang, Weiming
 and 
Qin, Jing
 and 
Heng, Pheng-Ann
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12245}

}
                
@article{
10.1111:cgf.12246,

journal = {Computer Graphics Forum},
title = {{
As-Rigid-As-Possible Distance Field Metamorphosis}},

author = {
Weng, Yanlin
 and 
Chai, Menglei
 and 
Xu, Weiwei
 and 
Tong, Yiying
 and 
Zhou, Kun
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12246}

}
                
@article{
10.1111:cgf.12247,

journal = {Computer Graphics Forum},
title = {{
An Efficient and Scalable Image Filtering Framework Using VIPS Fusion}},

author = {
Zhang, Jun
 and 
Chen, Xiuhong
 and 
Zhao, Yan
 and 
Li, H.
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12247}

}
                
@article{
10.1111:cgf.12248,

journal = {Computer Graphics Forum},
title = {{
Learning to Predict Localized Distortions in Rendered Images}},

author = {
Cadík, Martin
 and 
Herzog, Robert
 and 
Mantiuk, Rafal
 and 
Mantiuk, Radoslaw
 and 
Myszkowski, Karol
 and 
Seidel, Hans-Peter
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12248}

}
                
@article{
10.1111:cgf.12249,

journal = {Computer Graphics Forum},
title = {{
EnvyDepth: An Interface for Recovering Local Natural Illumination from Environment Maps}},

author = {
Banterle, Francesco
 and 
Callieri, Marco
 and 
Dellepiane, Matteo
 and 
Corsini, Massimiliano
 and 
Pellacini, Fabio
 and 
Scopigno, Roberto
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12249}

}
                
@article{
10.1111:cgf.12250,

journal = {Computer Graphics Forum},
title = {{
Efficient Shadow Removal Using Subregion Matching Illumination Transfer}},

author = {
Xiao, Chunxia
 and 
Xiao, Donglin
 and 
Zhang, Ling
 and 
Chen, Lin
},
year = {
2013},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd.},


ISSN = {1467-8659},

DOI = {
10.1111/cgf.12250}

}

Browse

Recent Submissions

Now showing 1 - 46 of 46
  • No Thumbnail Available
    Item
    Preface and Table of Contents
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) B. Levy, X. Tong, and K. Yin
  • No Thumbnail Available
    Item
    Dynamic Comics for Hierarchical Abstraction of 3D Animation Data
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Choi, Myung Geol; Noh, Seung-Tak; Komura, Taku; Igarashi, Takeo; B. Levy, X. Tong, and K. Yin
    Image storyboards of films and videos are useful for quick browsing and automatic video processing. A common approach for producing image storyboards is to display a set of selected key-frames in temporal order, which has been widely used for 2D video data. However, such an approach cannot be applied for 3D animation data because different information is revealed by changing parameters such as the viewing angle and the duration of the animation. Also, the interests of the viewer may be different from person to person. As a result, it is difficult to draw a single image that perfectly abstracts the entire 3D animation data. In this paper, we propose a system that allows users to interactively browse an animation and produce a comic sequence out of it. Each snapshot in the comic optimally visualizes a duration of the original animation, taking into account the geometry and motion of the characters and objects in the scene. This is achieved by a novel algorithm that automatically produces a hierarchy of snapshots from the input animation. Our user interface allows users to arrange the snapshots according to the complexity of the movements by the characters and objects, the duration of the animation and the page area to visualize the comic sequence. Our system is useful for quickly browsing through a large amount of animation data and semi-automatically synthesizing a storyboard from a long sequence of animation.
  • No Thumbnail Available
    Item
    Ontology-based Model for Chinese Calligraphy Synthesis
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Xia, Yang; Wu, Jiangqin; Gao, Pengcheng; Lin, Yuan; Mao, Tianjiao; B. Levy, X. Tong, and K. Yin
    There are lots of digitized Chinese calligraphic works written by ancient calligraphists in CADAL. Sometimes users want to generate a tablet or a piece of calligraphic work written by these calligraphists. However, some characters had not been written by them or though were ever written but are hard to read because of long time weathering. Furthermore, different works of the same calligraphist may have diverse styles. It is a great challenge to generate a new calligraphic character with particular style. In this paper, we present a novel approach to synthesize regular script calligraphic characters in the style of some specific calligraphic works. Our approach first processes original calligraphic resources by multi-level segmentation. Then, a domain ontology is established to supervise basic resources and to provide significant support for calligraphy synthesis. Finally, a novel algorithm is proposed to synthesize new calligraphic characters. We demonstrate the effectiveness of our method by showing various synthesized results in the style of different calligraphic works of Liu Gongquan.
  • No Thumbnail Available
    Item
    A GPU-based Streaming Algorithm for High-Resolution Cloth Simulation
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Tang, Min; Tong, Ruofeng; Narain, Rahul; Meng, Chang; Manocha, Dinesh; B. Levy, X. Tong, and K. Yin
    We present a GPU-based streaming algorithm to perform high-resolution and accurate cloth simulation. We map all the components of cloth simulation pipeline, including time integration, collision detection, collision response, and velocity updating to GPU-based kernels and data structures. Our algorithm perform intra-object and inter-object collisions, handles contacts and friction, and is able to accurately simulate folds and wrinkles. We describe the streaming pipeline and address many issues in terms of obtaining high throughput on many-core GPUs. In practice, our algorithm can perform high-fidelity simulation on a cloth mesh with 2M triangles using 3GB of GPU memory. We highlight the parallel performance of our algorithm on three different generations of GPUs. On a high-end NVIDIA Tesla K20c, we observe up to two orders of magnitude performance improvement as compared to a single-threaded CPU-based algorithm, and about one order of magnitude improvement over a 16-core CPU-based parallel implementation.
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    Constrainable Multigrid for Cloth
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Jeon, Inyong; Choi, Kwang-Jin; Kim, Tae-Yong; Choi, Bong-Ouk; Ko, Hyeong-Seok; B. Levy, X. Tong, and K. Yin
    We present a new technique which can handle both point and sliding constraints in the multigrid (MG) framework. Although the MG method can theoretically perform as fast as O(N), the development of a clothing simulator based on the MG method calls for solving an important technical challenge: handling the constraints. Resolving constrains has been difficult in MG because there has been no clear way to transfer the constraints existing in the finest level mesh to the coarser level meshes. This paper presents a new formulation based on soft constraints, which can coarsen the constraints defined in the finest level to the coarser levels. Experiments are performed which show that the proposed method can solve the linear system up to 4-9 times faster in comparison with the modified preconditioned conjugate gradient method (MPCG) without quality degradation. The proposed method is easy to implement and can be straightforwardly applied to existing clothing simulators which are based on implicit time integration.
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    Interactive Learning for Point-Cloud Motion Segmentation
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Sofer, Yerry; Hassner, Tal; Sharf, Andrei; B. Levy, X. Tong, and K. Yin
    Segmenting a moving foreground (fg) from its background (bg) is a fundamental step in many Machine Vision and Computer Graphics applications. Nevertheless, hardly any attempts have been made to tackle this problem in dynamic 3D scanned scenes. Scanned dynamic scenes are typically challenging due to noise and large missing parts. Here, we present a novel approach for motion segmentation in dynamic point-cloud scenes designed to cater to the unique properties of such data. Our key idea is to augment fg/bg classification with an active learning framework by refining the segmentation process in an adaptive manner. Our method initially classifies the scene points as either fg or bg in an un-supervised manner. This, by training discriminative RBF-SVM classifiers on automatically labeled, high-certainty fg/bg points. Next, we adaptively detect unreliable classification regions (i.e. where fg/bg separation is uncertain), locally add more training examples to better capture the motion in these areas, and re-train the classifiers to fine-tune the segmentation. This not only improves segmentation accuracy, but also allows our method to perform in a coarse-to-fine manner, thereby efficiently process high-density point-clouds. Additionally, we present a unique interactive paradigm for enhancing this learning process, by using a manual editing tool. The user explicitly edits the RBF-SVM decision borders in unreliable regions in order to refine and correct the classification. We provide extensive qualitative and quantitative experiments on both real (scanned) and synthetic dynamic scenes.
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    Synthesizing Two-character Interactions by Merging Captured Interaction Samples with their Spacetime Relationships
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Chan, Jacky C. P.; Tang, Jeff K. T.; Leung, Howard; B. Levy, X. Tong, and K. Yin
    Existing synthesis methods for closely interacting virtual characters relied on user-specified constraints such as the reaching positions and the distance between body parts. In this paper, we present a novel method for synthesizing new interacting motion by composing two existing interacting motion samples without the need to specify the constraints manually. Our method automatically detects the type of interactions contained in the inputs and determines a suitable timing for the interaction composition by analyzing the spacetime relationships of the input characters. To preserve the features of the inputs in the synthesized interaction, the two inputs will be aligned and normalized according to the relative distance and orientation of the characters from the inputs. With a linear optimization method, the output is the optimal solution to preserve the close interaction of two characters and the local details of individual character behavior. The output animations demonstrated that our method is able to create interactions of new styles that combine the characteristics of the original inputs.
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    Stroke-guided Image Synthesis for Skeletal Structure Editing
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Luo, Sheng-Jie; Lin, Chin-Yu; Shen, I-Chao; Chen, Bing-Yu; B. Levy, X. Tong, and K. Yin
    Creating variations of an image object is an important task, which usually requires manipulating the skeletal structure of the object. However, most existing methods (such as image deformation) only allow for stretching the skeletal structure of an object: modifying skeletal topology remains a challenge. This paper presents a technique for synthesizing image objects with different skeletal structures while respecting to an input image object. To apply this technique, a user firstly annotates the skeletal structure of the input object by specifying a number of strokes in the input image, and draws corresponding strokes in an output domain to generate new skeletal structures. Then, a number of the example texture pieces are sampled along the strokes in the input image and pasted along the strokes in the output domain with their orientations. The result is obtained by optimizing the texture sampling and seam computation. The proposed method is successfully used to synthesize challenging skeletal structures, such as skeletal branches, and a wide range of image objects with various skeletal structures, to demonstrate its effectiveness.
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    Topology Aware Data-Driven Inverse Kinematics
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Ho, Edmond S. L.; Shum, Hubert P. H.; Cheung, Yiu-ming; Yuen, P. C.; B. Levy, X. Tong, and K. Yin
    Creating realistic human movement is a time consuming and labour intensive task. The major difficulty is that the user has to edit individual joints while maintaining an overall realistic and collision free posture. Previous research suggests the use of data-driven inverse kinematics, such that one can focus on the control of a few joints, while the system automatically composes a natural posture. However, as a common problem of kinematics synthesis, penetration of body parts is difficult to avoid in complex movements. In this paper, we propose a new data-driven inverse kinematics framework that conserves the topology of the synthesizing postures. Our system monitors and regulates the topology changes using the Gauss Linking Integral (GLI), such that penetration can be efficiently prevented. As a result, complex motions with tight body movements, as well as those involving interaction with external objects, can be simulated with minimal manual intervention. Experimental results show that using our system, the user can create high quality human motion in real-time by controlling a few joints using a mouse or a multi-touch screen. The movement generated is both realistic and penetration free. Our system is best applied for interactive motion design in computer animations and games.
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    Hair Interpolation for Portrait Morphing
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Weng, Yanlin; Wang, Lvdi; Li, Xiao; Chai, Menglei; Zhou, Kun; B. Levy, X. Tong, and K. Yin
    In this paper we study the problem of hair interpolation: given two 3D hair models, we want to generate a sequence of intermediate hair models that transform from one input to another both smoothly and aesthetically pleasing. We propose an automatic method that efficiently calculates a many-to-many strand correspondence between two or more given hair models, taking into account the multi-scale clustering structure of hair. Experiments demonstrate that hair interpolation can be used for producing more vivid portrait morphing effects and enabling a novel example-based hair styling methodology, where a user can interactively create new hairstyles by continuously exploring a ''style space'' spanning multiple input hair models.
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    Garment Modeling from a Single Image
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Zhou, Bin; Chen, Xiaowu; Fu, Qiang; Guo, Kan; Tan, Ping; B. Levy, X. Tong, and K. Yin
    Modeling of realistic garments is essential for online shopping and many other applications including virtual characters. Most of existing methods either require a multi-camera capture setup or a restricted mannequin pose. We address the garment modeling problem according to a single input image. We design an all-pose garment outline interpretation, and a shading-based detail modeling algorithm. Our method first estimates the mannequin pose and body shape from the input image. It further interprets the garment outline with an oriented facet decided according to the mannequin pose to generate the initial 3D garment model. Shape details such as folds and wrinkles are modeled by shape-from-shading techniques, to improve the realism of the garment model. Our method achieves similar result quality as prior methods from just a single image, significantly improving the flexibility of garment modeling.
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    Fast Image-Based Modeling of Astronomical Nebulae
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Wenger, Stephan; Lorenz, Dirk; Magnor, Marcus; B. Levy, X. Tong, and K. Yin
    Astronomical nebulae are among the most complex and visually appealing phenomena known outside the bounds of the Solar System. However, our fixed vantage point on Earth limits us to a single known view of these objects, and their intricate volumetric structure cannot be recovered directly. Recent approaches to reconstructing a volumetric 3D model use the approximate symmetry inherent to many nebulae, but require several hours of computation time on large multi-GPU clusters. We present a novel reconstruction algorithm based on group sparsity that reaches or even exceeds the quality of prior results while taking only a fraction of the time on a conventional desktop PC, thereby enabling end users in planetariums or educational facilities to produce high-quality content without expensive hardware or manual modeling. In principle, our approach can be generalized to other transparent phenomena with arbitrary types of user-specified symmetries.
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    Lighting Simulation of Augmented Outdoor Scene Based on a Legacy Photograph
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Xing, Guanyu; Zhou, Xuehong; Peng, Qunsheng; Liu, Yanli; Qin, Xueying; B. Levy, X. Tong, and K. Yin
    We propose a novel approach to simulate the illumination of augmented outdoor scene based on a legacy photograph. Unlike previous works which only take surface radiosity or lighting related prior information as the basis of illumination estimation, our method integrates both of these two items. By adopting spherical harmonics, we deduce a linear model with only six illumination parameters. The illumination of an outdoor scene is finally calculated by solving a linear least square problem with the color constraint of the sunlight and the skylight. A high quality environment map is then set up, leading to realistic rendering results. We also explore the problem of shadow casting between real and virtual objects without knowing the geometry of objects which cast shadows. An efficient method is proposed to project complex shadows (such as tree's shadows) on the ground of the real scene to the surface of the virtual object with texture mapping. Finally, we present an unified scheme for image composition of a real outdoor scene with virtual objects ensuring their illumination consistency and shadow consistency. Experiments demonstrate the effectiveness and flexibility of our method.
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    Eye-Centered Color Adaptation in Global Illumination
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Gruson, Adrien; Ribardière, Mickael; Cozot, Remi; B. Levy, X. Tong, and K. Yin
    Color adaptation is a well known ability of the human visual system (HVS). Colors are perceived as constant even though the illuminant color changes. Indeed, the perceived color of a diffuse white sheet of paper is still white even though it is illuminated by a single orange tungsten light, whereas it is orange from a physical point of view. Unfortunately global illumination algorithms only focus on the physics aspects of light transport. The ouput of a global illuminantion engine is an image which has to undergo chromatic adaptation to recover the color as perceived by the HVS. In this paper, we propose a new color adaptation method well suited to global illumination. This method estimates the adaptation color by averaging the irradiance color arriving at the eye. Unlike other existing methods, our approach is not limited to the view frustrum, as it considers the illumination from all the scene. Experiments have shown that our method outperforms the state of the art methods.
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    Robust Denoising using Feature and Color Information
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Rousselle, Fabrice; Manzi, Marco; Zwicker, Matthias; B. Levy, X. Tong, and K. Yin
    We propose a method that robustly combines color and feature buffers to denoise Monte Carlo renderings. On one hand, feature buffers, such as per pixel normals, textures, or depth, are effective in determining denoising filters because features are highly correlated with rendered images. Filters based solely on features, however, are prone to blurring image details that are not well represented by the features. On the other hand, color buffers represent all details, but they may be less effective to determine filters because they are contaminated by the noise that is supposed to be removed. We propose to obtain filters using a combination of color and feature buffers in an NL-means and cross-bilateral filtering framework. We determine a robust weighting of colors and features using a SURE-based error estimate. We show significant improvements in subjective and quantitative errors compared to the previous state-of-the-art. We also demonstrate adaptive sampling and space-time filtering for animations.
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    Artistic QR Code Embellishment
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Lin, Yi-Shan; Luo, Sheng-Jie; Chen, Bing-Yu; B. Levy, X. Tong, and K. Yin
    A QR code is a two-dimensional barcode that encodes information. A standard QR code contains only regular black and white squares, and thus is unattractive. This paper proposes a novel framework for embellishing a standard QR code, to make it both attractive and recognizable by any human while maintaining its scanability. The proposed method is inspired by artistic methods. A QR code is typically embellished by stylizing the squares and embedding images into it. In the proposed framework, the regular squares are reshaped using a binary examplar, to make their local appearances resemble the example shape. Additionally, an error-aware warping technique for deforming the embedded image is proposed; it minimizes the error in the QR code that is generated by the embedding of the image to optimize the readability of the code. The proposed algorithm yields lower data error than previous global transformation techniques because the warping can locally deform the embedded image to conform to the squares that surround it. The proposed framework was examined by using it to embellish an extensive set of QR codes and to test the readability with various commercial QR code readers.
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    Second-Order Approximation for Variance Reduction in Multiple Importance Sampling
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Lu, Heqi; Pacanowski, Romain; Granier, Xavier; B. Levy, X. Tong, and K. Yin
    Monte Carlo Techniques are widely used in Computer Graphics to generate realistic images. Multiple Importance Sampling reduces the impact of choosing a dedicated strategy by balancing the number of samples between different strategies. However, an automatic choice of the optimal balancing remains a difficult problem. Without any scene characteristics knowledge, the default choice is to select the same number of samples from different strategies and to use them with heuristic techniques (e.g., balance, power or maximum). In this paper, we introduce a second-order approximation of variance for balance heuristic. Based on this approximation, we introduce an automatic distribution of samples for direct lighting without any prior knowledge of the scene characteristics. We demonstrate that for all our test scenes (with different types of materials, light sources and visibility complexity), our method actually reduces variance in average.We also propose an implementation with low overhead for offline and GPU applications. We hope that this approach will help developing new balancing strategies.
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    Interactive Physics-based Ink Splattering Art Creation
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Lei, Su-Ian Eugene; Chen, Ying-Chieh; Chen, Hsiang-Ting; Chang, Chun-Fa; B. Levy, X. Tong, and K. Yin
    This paper presents an interactive system for ink splattering, a form of abstract art that artists splat ink onto the canvas. The default input device of our system is a pressure-sensitive 2D stylus, the most common sketching tool for digital artists, and we propose two interaction mode: ink-flicking mode and ink-dripping mode, that are designed to be analogous to the artistic techniques of ink splattering in real world. The core of our ink splattering system is a novel three-stage ink splattering framework that simulates the physics-based interaction of ink with different mediums including brush heads, air and paper. We have implemented the physical engine in CUDA and the whole simulation process runs at interactive speed.
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    Modeling by Drawing with Shadow Guidance
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Fan, Lubin; Wang, Ruimin; Xu, Linlin; Deng, Jiansong; Liu, Ligang; B. Levy, X. Tong, and K. Yin
    Modeling 3D objects is difficult, especially for the user who lacks the knowledge on 3D geometry or even on 2D sketching. In this paper, we present a novel sketch-based modeling system which allows novice users to create 3D custom models by assembling parts based on a database of pre-segmented 3D models. Different from previous systems, our system supports the user with visualized and meaningful shadow guidance under his strokes dynamically to guide the user to convey his design concept easily and quickly. Our system interprets the user's strokes as similarity queries into database to generate the shadow image for guiding the user's further drawing and returns the 3D candidate parts for modeling simultaneously. Moreover, our system preserves the high-level structure in generated models based on prior knowledge pre-analyzed from the database, and allows the user to create custom parts with geometric variations. We demonstrate the applicability and effectiveness of our modeling system with human subjects and present various models designed using our system.
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    Soft Folding
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Zhu, Lifeng; Igarashi, Takeo; Mitani, Jun; B. Levy, X. Tong, and K. Yin
    We introduce soft folding, a new interactive method for designing and exploring thin-plate forms. A user specifies sharp and soft folds as two-dimensional(2D) curves on a flat sheet, along with the fold magnitude and sharpness of each. Then, based on the soft folds, the system computes the three-dimensional(3D) folded shape. Internally, the system first computes a fold field, which defines local folding operations on a flat sheet. A fold field is a generalization of a discrete fold graph in origami, replacing a graph with sharp folds with a continuous field with soft folds. Next, local patches are folded independently according to the fold field. Finally, a globally folded 3D shape is obtained by assembling the locally folded patches. This algorithm computes an approximation of 3D developable surfaces with user-defined soft folds at an interactive speed. The user can later apply nonlinear physical simulation to generate more realistic results. Experimental results demonstrated that soft folding is effective for producing complex folded shapes with controllable sharpness.
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    TrayGen: Arranging Objects for Exhibition and Packaging
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Yang, Yong-Liang; Huang, Qi-Xing; B. Levy, X. Tong, and K. Yin
    We present a framework, called TrayGen, to generate tray designs for the exhibition and packaging of a collection of objects. Based on principles from shape perception and visual merchandising, we abstract a number of design guidelines on how to organize the objects on the tray for the exhibition of their individual features and mutual relationships. Our framework realizes these guidelines by analyzing geometric shapes of the objects and optimizing their arrangement. We demonstrate that the resultant tray designs not only save space, but also highlight the characteristic of each object and the inter-relations between objects.
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    Guided Real-Time Scanning of Indoor Objects
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Kim, Young Min; Mitra, Niloy J.; Huang, Qixing; Guibas, Leonidas; B. Levy, X. Tong, and K. Yin
    Advances in 3D acquisition devices provide unprecedented opportunities for quickly scanning indoor environments. Such raw scans, however, are often noisy, incomplete, and significantly corrupted, making semantic scene understanding difficult, if not impossible. Unfortunately, in most existing workflows, scan quality is assessed after the scanning stage is completed, making it cumbersome to correct for significant missing data by additional scanning. In this work, we present a guided real-time scanning setup, wherein the incoming 3D data stream is continuously analyzed, and the data quality is automatically assessed. While the user is scanning an object, the proposed system discovers and highlights potential missing parts, thus guiding the operator (or an autonomous robot) as where to scan next. The proposed system assesses the quality and completeness of the 3D scan data by comparing to a large collection of commonly occurring indoor man-made objects using an efficient, robust, and effective scan descriptor. We have tested the system on a large number of simulated and real setups, and found the guided interface to be effective even in cluttered and complex indoor environments.
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    The POP Buffer: Rapid Progressive Clustering by Geometry Quantization
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Limper, Max; Jung, Yvonne; Behr, Johannes; Alexa, Marc; B. Levy, X. Tong, and K. Yin
    Within this paper, we present a novel, straightforward progressive encoding scheme for general triangle soups, which is particularly well-suited for mobile and Web-based environments due to its minimal requirements on the client's hardware and software. Our rapid encoding method uses a hierarchy of quantization to effectively reorder the original primitive data into several nested levels of detail. The resulting stateless buffer can progressively be transferred as-is to the GPU, where clustering is efficiently performed in parallel during rendering. We combine our approach with a crack-free mesh partitioning scheme to obtain a straightforward method for fast streaming and basic view-dependent LOD control.
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    A Semi-Lagrangian Closest Point Method for Deforming Surfaces
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Auer, Stefan; Westermann, Rüdiger; B. Levy, X. Tong, and K. Yin
    We present an Eulerian method for the real-time simulation of intrinsic fluid dynamics effects on deforming surfaces. Our method is based on a novel semi-Lagrangian closest point method for the solution of partial differential equations on animated triangle meshes.We describe this method and demonstrate its use to com- pute and visualize flow and wave propagation along such meshes at high resolution and speed. Underlying our technique is the efficient conversion of an animated triangle mesh into a time-dependent implicit repre- sentation based on closest surface points. The proposed technique is unconditionally stable with respect to the surface deformation and, in contrast to comparable Lagrangian techniques, its precision does not depend on the level of detail of the surface triangulation.
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    Implicit Integration for Particle-based Simulation of Elasto-Plastic Solids
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Zhou, Yahan; Lun, Zhaoliang; Kalogerakis, Evangelos; Wang, Rui; B. Levy, X. Tong, and K. Yin
    We present a novel particle-based method for stable simulation of elasto-plastic materials. The main contribution of our method is an implicit numerical integrator, using a physically-based model, for computing particles that undergo both elastic and plastic deformations. The main advantage of our implicit integrator is that it allows the use of large time steps while still preserving stable and physically plausible simulation results. As a key component of our algorithm, at each time step we compute the particle positions and velocities based on a sparse linear system, which we solve efficiently on the graphics hardware. Compared to existing techniques, our method allows for a much wider range of stiffness and plasticity settings. In addition, our method can significantly reduce the computation cost for certain range of material types. We demonstrate fast and stable simulations for a variety of elasto-plastic materials, ranging from highly stiff elastic materials to highly plastic ones.
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    Combustion Waves on the Point Set Surface
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Jeong, SoHyeon; Kim, Chang-Hun; B. Levy, X. Tong, and K. Yin
    This paper introduces a combustion model of heat transfer and fuel consumption for the propagation of a fire front on a point cloud surface. The heat transfer includes the heat advection by the airflow as well as diffusion, chemical reaction, and heat loss to generate complex, but controllable heat flows with a designed airflow velocity. For the stable heat advection, we solve a semi-Lagrangian method on point samples using discrete exponential maps to trace the position from which the wind blows while preserving the geodesic distance. We also propose angular Voronoi weights for a discrete Laplace-Beltrami operator that shows better isotropic diffusion on the inhomogeneous distribution of point clouds than the cotangent or moving least-squares schemes. We demonstrate a diversity of burning scenarios by incorporating factors affecting the fire spreading such as buoyancy and object geometries in the airflow velocity fields, or by synthesizing patterns.
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    Efficient Smoke Simulation on Curvilinear Grids
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Azevedo, Vinicius C.; Oliveira, Manuel M.; B. Levy, X. Tong, and K. Yin
    We present an efficient approach for performing smoke simulation on curvilinear grids. Our technique is based on a fast unconditionally-stable advection algorithm and on a new and efficient solution to enforce mass conservation. It uses a staggered-grid variable arrangement, and has linear cost on the number of grid cells. Our method naturally integrates itself with overlapping-grid techniques, lending to an efficient way of producing highly-realistic animations of dynamic scenes. Compared to approaches based on regular grids traditionally used in computer graphics, our method allows for better representation of boundary conditions, with just a small increment in computational cost. Thus, it can be used to evaluate aerodynamic properties, possibly enabling unexplored applications in computer graphics, such as interactive computation of lifting forces on complex objects.We demonstrate the effectiveness of our approach, both in 2-D and 3-D, through a variety of high-quality smoke animations.
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    A Progressive Tri-level Segmentation Approach for Topology-Change-Aware Video Matting
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Ju, Jinlong; Wang, Jue; Liu, Yebin; Wang, Haoqian; Dai, Qionghai; B. Levy, X. Tong, and K. Yin
    Previous video matting approaches mostly adopt the ''binary segmentation + matting'' strategy, i.e., first segment each frame into foreground and background regions, then extract the fine details of the foreground boundary using matting techniques. This framework has several limitations due to the fact that binary segmentation is employed. In this paper, we propose a new supervised video matting approach. Instead of applying binary segmentation, we explicitly model segmentation uncertainty in a novel tri-level segmentation procedure. The segmentation is done progressively, enabling us to handle difficult cases such as large topology changes, which are challenging to previous approaches. The tri-level segmentation results can be naturally fed into matting techniques to generate the final alpha mattes. Experimental results show that our system can generate high quality results with less user inputs than the state-of-the-art methods.
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    Learning and Applying Color Styles From Feature Films
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Xue, Su; Agarwala, Aseem; Dorsey, Julie; Rushmeier, Holly; B. Levy, X. Tong, and K. Yin
    Directors employ a process called ''color grading'' to add color styles to feature films. Color grading is used for a number of reasons, such as accentuating a certain emotion or expressing the signature look of a director. We collect a database of feature film clips and label them with tags such as director, emotion, and genre. We then learn a model that maps from the low-level color and tone properties of film clips to the associated labels. This model allows us to examine a number of common hypotheses on the use of color to achieve goals, such as specific emotions. We also describe a method to apply our learned color styles to new images and videos. Along with our analysis of color grading techniques, we demonstrate a number of images and videos that are automatically filtered to resemble certain film styles.
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    Multiplane Video Stabilization
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Wang, Zhong-Qiang; Zhang, Lei; Huang, Hua; B. Levy, X. Tong, and K. Yin
    This paper presents a novel video stabilization approach by leveraging the multiple planes structure of video scene to stabilize inter-frame motion. As opposed to previous stabilization procedure operating in a single plane, our approach primarily deals with multiplane videos and builds their multiple planes structure for performing stabilization in respective planes. Hence, a robust plane detection scheme is devised to detect multiple planes by classifying feature trajectories according to reprojection errors generated by plane induced homographies. Then, an improved planar stabilization technique is applied by conforming to the compensated homography in each plane. Finally, multiple stabilized planes are coherently fused by content-preserving image warps to obtain the output stabilized frames. Our approach does not need any stereo reconstruction, yet is able to produce commendable results due to awareness of multiple planes structure in the stabilization. Experimental results demonstrate the effectiveness and efficiency of our approach to robust stabilization on multiplane videos.
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    Evaluation of Tone Mapping Operators for HDR-Video
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Eilertsen, Gabriel; Wanat, Robert; Mantiuk, Rafal K.; Unger, Jonas; B. Levy, X. Tong, and K. Yin
    Eleven tone-mapping operators intended for video processing are analyzed and evaluated with camera-captured and computer-generated high-dynamic-range content. After optimizing the parameters of the operators in a formal experiment, we inspect and rate the artifacts (flickering, ghosting, temporal color consistency) and color rendition problems (brightness, contrast and color saturation) they produce. This allows us to identify major problems and challenges that video tone-mapping needs to address. Then, we compare the tone-mapping results in a pair-wise comparison experiment to identify the operators that, on average, can be expected to perform better than the others and to assess the magnitude of differences between the best performing operators.
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    Animated 3D Line Drawings with Temporal Coherence
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Xu, Xiang; Seah, Hock Soon; Quah, Chee Kwang; B. Levy, X. Tong, and K. Yin
    Producing traditional animation is a laborious task where the key drawings are first drawn by artists and thereafter inbetween drawings are created, whether it is by hand or computer-assisted. Auto-inbetweening of these 2D key drawings by computer is a non-trivial task as 3D depths are missing. An alternate approach is to generate all the drawings by extracting lines directly from animated 3D models frame by frame, concatenating and rendering them together into an animation. However, animation quality generated using this straightforward method bears two problems. Firstly, the animation contains unsatisfactory visual artifacts such as line flickering and popping. This is especially pronounced when the lines are extracted using high-order derivatives, such as ridges and valleys, from 3D models represented in triangle meshes. Secondly, there is a lack of temporal continuity as each drawing is generated without taking its neighboring drawings into consideration. In this paper, we propose an improved approach over the straightforward method by transferring extracted 3D line drawings of each frame into individual 3D lines and processing them along the time domain. Our objective is to minimize the visual artifacts and incorporate temporal relationship of individual lines throughout the entire animation sequence. This is achieved by creating correspondent trajectory of each line from each frame and applying global optimization on each trajectory. To realize this target, we present a fully automatic novel approach, which consists of (1) a line matching algorithm, (2) an optimizing algorithm, taking into account both the variations of numbers and lengths of 3D lines in each frame, and (3) a robust tracing method for transferring collections of line segments extracted from the 3D models into individual lines. We evaluate our approach on several animated model sequences to demonstrate its effectiveness in producing line drawing animations with temporal coherence.
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    Still-Frame Simulation for Fire Effects of Images
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Son, Minjung; Kim, Byungmoon; Wilensky, Gregg; Lee, Seungyong; B. Levy, X. Tong, and K. Yin
    We propose various simulation strategies to generate single-frame fire effects for images, as opposed to multiframe fire effects for animations. To accelerate 3D simulation and to provide a user with early hints on the final effect, we propose a 2D-guided 3D simulation approach, which runs a faster 2D simulation first, and then guides 3D simulation using the 2D simulation result. To achieve this, we explore various boundary conditions and develop a constrained projection method. Since only the final frame will be used while intermediate frames are abandoned, earlier intermediate frames can take larger time steps and have large noise applied, quickly generating turbulent flow structures. As the final frame approaches, we increase the flow quality by reducing the time step and not adding any noise. This adaptive time stepping allows us to use more computational resource near or at the final frame. We also develop divergence and buoyancy modification methods to guide flames along arbitrary, even physically implausible, directions. Our simulation methods can effectively and efficiently generate a variety of fire effects useful for image decoration.
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    Boundary-Aware Extinction Mapping
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Gautron, Pascal; Delalandre, Cyril; Marvie, Jean-Eudes; Lecocq, Pascal; B. Levy, X. Tong, and K. Yin
    We introduce Boundary-Aware Extinction Maps for interactive rendering of massive heterogeneous volumetric datasets. Our approach is based on the projection of the extinction along light rays into a boundary-aware function space, focusing on the most relevant sections of the light paths. This technique also provides an alternative representation of the set of participating media, allowing scattering simulation methods to be applied on arbitrary volume representations. Combined with a simple out-of-core rendering framework, Boundary-Aware Extinction Maps are valuable tools for interactive applications as well as production previsualization and rendering.
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    Adaptive Ray-bundle Tracing with Memory Usage Prediction: Efficient Global Illumination in Large Scenes
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Tokuyoshi, Yusuke; Sekine, Takashi; Silva, Tiago da; Kanai, Takashi; B. Levy, X. Tong, and K. Yin
    This paper proposes an adaptive rendering technique for ray-bundle tracing. Ray-bundle tracing can be done by per-pixel linked-list construction on a GPU rasterization pipeline. This rasterization based approach offers significant benefits for the efficient generation of light maps (e.g., hardware acceleration, tessellation, and recycling of shaders used in real-time graphics). However, it is inapplicable to large and complex scenes due to the limited capacity of the GPU memory because it requires a high-resolution frame buffer and high-capacity node buffer for the linked-lists. In addition, memory overflow can potentially occur on the per-pixel linked-list since the memory usage of the lists is usually unknown before the rendering process. We introduce an adaptive tiling technique with memory usage prediction. Our method uses an appropriately tiled frame buffer, thus eliminating almost all of the overflow risks thanks to our adaptive tile subdivision scheme. Using this technique, we are able to render high-quality light maps of large and complex scenes which cannot be computed using previous ray-bundle based methods.
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    A Programmable Graphics Processor based on Partial Stream Rewriting
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Middendorf, Lars; Haubelt, Christian; B. Levy, X. Tong, and K. Yin
    Current graphics processing units (GPU) typically offer only a limited number of programmable pipeline stages, whose usage, data flow and topology are mostly fixed. Although a more flexible, custom rendering pipeline can be emulated using the compute functionality of existing GPUs, this approach requires to manage work queues, synchronization, and scheduling in software. In this paper, we present a hardware architecture for a novel, programmable rendering pipeline, which is based on a circulating stream of data and control tokens that are iteratively modified via pattern matching. Our architecture provides light-weight mechanisms for dynamic thread creation, lock-free synchronization, and scheduling to support recursion, dynamic shader linkage and custom primitive types. A hardware prototype, running complex examples, demonstrates the improved reconfigurability also the scalability of our graphics architecture.
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    Improving Memory Space Efficiency of Kd-tree for Real-time Ray Tracing
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Choi, Byeongjun; Chang, Byungjoon; Ihm, Insung; B. Levy, X. Tong, and K. Yin
    Compared with its competitors such as the bounding volume hierarchy, a drawback of the kd-tree structure is that a large number of triangles are repeatedly duplicated during its construction, which often leads to inefficient, large and tall binary trees with high triangle redundancy. In this paper, we propose a space-efficient kd-tree representation where, unlike commonly used methods, an inner node is allowed to optionally store a reference to a triangle, so highly redundant triangles in a kd-tree can be culled from the leaf nodes and moved to the inner nodes. To avoid the construction of ineffective kd-trees entailing computational inefficiencies due to early, possibly unnecessary, ray-triangle intersection calculations that now have to be performed in the inner nodes during the kd-tree traversal, we present heuristic measures for determining when and how to choose triangles for inner nodes during kd-tree construction. Based on these metrics, we describe how the new form of kd-tree is constructed and stored compactly using a carefully designed data layout. Our experiments with several example scenes showed that our kd-tree representation technique significantly reduced the memory requirements for storing the kd-tree structure, while effectively suppressing the unavoidable frame-rate degradation observed during ray tracing.
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    Level-of-Detail Streaming and Rendering using Bidirectional Sparse Virtual Texture Functions
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Schwartz, Christopher; Ruiters, Roland; Klein, Reinhard; B. Levy, X. Tong, and K. Yin
    Bidirectional Texture Functions (BTFs) are among the highest quality material representations available today and thus well suited whenever an exact reproduction of the appearance of a material or complete object is required. In recent years, BTFs have started to find application in various industrial settings and there is also a growing interest in the cultural heritage domain. BTFs are usually measured from real-world samples and easily consist of tens or hundreds of gigabytes. By using data-driven compression schemes, such as matrix or tensor factorization, a more compact but still faithful representation can be derived. This way, BTFs can be employed for real-time rendering of photo-realistic materials on the GPU. However, scenes containing multiple BTFs or even single objects with high-resolution BTFs easily exceed available GPU memory on today's consumer graphics cards unless quality is drastically reduced by the compression. In this paper, we propose the Bidirectional Sparse Virtual Texture Function, a hierarchical level-of-detail approach for the real-time rendering of large BTFs that requires only a small amount of GPU memory. More importantly, for larger numbers or higher resolutions, the GPU and CPU memory demand grows only marginally and the GPU workload remains constant. For this, we extend the concept of sparse virtual textures by choosing an appropriate prioritization, finding a trade off between factorization components and spatial resolution. Besides GPU memory, the high demand on bandwidth poses a serious limitation for the deployment of conventional BTFs. We show that our proposed representation can be combined with an additional transmission compression and then be employed for streaming the BTF data to the GPU from from local storage media or over the Internet. In combination with the introduced prioritization this allows for the fast visualization of relevant content in the users field of view and a consecutive progressive refinement.
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    Symmetry Robust Descriptor for Non-Rigid Surface Matching
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Zhang, Zhiyuan; Yin, KangKang; Foong, Kelvin W. C.; B. Levy, X. Tong, and K. Yin
    In this paper, we propose a novel shape descriptor that is robust in differentiating intrinsic symmetric points on geometric surfaces. Our motivation is that even the state-of-the-art shape descriptors and non-rigid surface matching algorithms suffer from symmetry flips. They cannot differentiate surface points that are symmetric or near symmetric. Hence a left hand of one human model may be matched to a right hand of another. Our Symmetry Robust Descriptor (SRD) is based on a signed angle field, which can be calculated from the gradient fields of the harmonic fields of two point pairs. Experiments show that the proposed shape descriptor SRD results in much less symmetry flips compared to alternative methods. We further incorporate SRD into a stand-alone algorithm to minimize symmetry flips in finding sparse shape correspondences. SRD can also be used to augment other modern non-rigid shape matching algorithms with ease to alleviate symmetry confusions.
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    Polar NURBS Surface with Curvature Continuity
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Shi, Kan-Le; Yong, Jun-Hai; Tang, Lei; Sun, Jia-Guang; Paul, Jean-Claude; B. Levy, X. Tong, and K. Yin
    Polar NURBS surface is a kind of periodic NURBS surface, one boundary of which shrinks to a degenerate polar point. The specific topology of its control-point mesh offers the ability to represent a cap-like surface, which is common in geometric modeling. However, there is a critical and challenging problem that hinders its application: curvature continuity at the extraordinary singular pole. We first propose a sufficient and necessary condition of curvature continuity at the pole. Then, we present constructive methods for the two key problems respectively: how to construct a polar NURBS surface with curvature continuity and how to reform an ordinary polar NURBS surface to curvature continuous. The algorithms only depend on the symbolic representation and operations of NURBS, and they introduce no restrictions on the degree or the knot vectors. Examples and comparisons demonstrate the applications of the curvature-continuous polar NURBS surface in hole-filling and free-shape modeling.
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    Coarse-to-Fine Normal Filtering for Feature-Preserving Mesh Denoising Based on Isotropic Subneighborhoods
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Zhu, Lei; Wie, Mingqiang; Yu, Jinze; Wang, Weiming; Qin, Jing; Heng, Pheng-Ann; B. Levy, X. Tong, and K. Yin
    State-of-the-art normal filters usually denoise each face normal using its entire anisotropic neighborhood. However, enforcing these filters indiscriminately on the anisotropic neighborhood will lead to feature blurring, especially in challenging regions with shallow features. We develop a novel mesh denoising framework which can effectively preserve features with various sizes. Our idea is inspired by the observation that the underlying surface of a noisy mesh is piecewise smooth. In this regard, it is more desirable that we denoise each face normal within its piecewise smooth region (we call such a region as an isotropic subneighborhood) instead of using the anisotropic neighborhood. To achieve this, we first classify mesh faces into several types using a face normal tensor voting and then perform a normal filter to obtain a denoised coarse normal field. Based on the results of normal classification and the denoised coarse normal field, we segment the anisotropic neighborhood of every feature face into a number of isotropic subneighborhoods via local spectral clustering. Thus face normal filtering can be performed again on the isotropic subneighborhoods and produce a more accurate normal field. Extensive tests on various models demonstrate that our method can achieve better performance than state-of-the-art normal filters, especially in challenging regions with features.
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    As-Rigid-As-Possible Distance Field Metamorphosis
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Weng, Yanlin; Chai, Menglei; Xu, Weiwei; Tong, Yiying; Zhou, Kun; B. Levy, X. Tong, and K. Yin
    Widely used for morphing between objects with arbitrary topology, distance field interpolation (DFI) handles topological transition naturally without the need for correspondence or remeshing, unlike surface-based interpolation approaches. However, lack of correspondence in DFI also leads to ineffective control over the morphing process. In particular, unless the user specifies a dense set of landmarks, it is not even possible to measure the distortion of intermediate shapes during interpolation, let alone control it. To remedy such issues, we introduce an approach for establishing correspondence between the interior of two arbitrary objects, formulated as an optimal mass transport problem with a sparse set of landmarks. This correspondence enables us to compute non-rigid warping functions that better align the source and target objects as well as to incorporate local rigidity constraints to perform as-rigid-as-possible DFI. We demonstrate how our approach helps achieve flexible morphing results with a small number of landmarks.
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    An Efficient and Scalable Image Filtering Framework Using VIPS Fusion
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Zhang, Jun; Chen, Xiuhong; Zhao, Yan; Li, H.; B. Levy, X. Tong, and K. Yin
    Edge-preserving image filtering is a valuable tool for a variety of applications in image processing and computer vision. Motivated by a new simple but effective local Laplacian filter, we propose a scalable and efficient image filtering framework to extend this edge-preserving image filter and construct an uniform implementation in O(N) time. The proposed framework is built upon a practical global-to-local strategy. The input image is first remapped globally by a series of tentative remapping functions to generate a virtual candidate image sequence (Virtual Image Pyramid Sequence, VIPS). This sequence is then recombined locally to a single output image by a flexible edge-aware pixel-level fusion rule. To avoid halo artifacts, both the output image and the virtual candidate image sequence are transformed into multi-resolution pyramid representations. Four examples, single image de-hazing, multi-exposure fusion, fast edge-preserving filtering and tone-mapping, are presented as the concrete applications of the proposed framework. Experiments on filtering effect and computational efficiency indicate that the proposed framework is able to build a wide range of fast image filtering that yields visually compelling results.
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    Learning to Predict Localized Distortions in Rendered Images
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Cadík, Martin; Herzog, Robert; Mantiuk, Rafal; Mantiuk, Radoslaw; Myszkowski, Karol; Seidel, Hans-Peter; B. Levy, X. Tong, and K. Yin
    In this work, we present an analysis of feature descriptors for objective image quality assessment. We explore a large space of possible features including components of existing image quality metrics as well as many traditional computer vision and statistical features. Additionally, we propose new features motivated by human perception and we analyze visual saliency maps acquired using an eye tracker in our user experiments. The discriminative power of the features is assessed by means of a machine learning framework revealing the importance of each feature for image quality assessment task. Furthermore, we propose a new data-driven full-reference image quality metric which outperforms current state-of-the-art metrics. The metric was trained on subjective ground truth data combining two publicly available datasets. For the sake of completeness we create a new testing synthetic dataset including experimentally measured subjective distortion maps. Finally, using the same machine-learning framework we optimize the parameters of popular existing metrics.
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    EnvyDepth: An Interface for Recovering Local Natural Illumination from Environment Maps
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Banterle, Francesco; Callieri, Marco; Dellepiane, Matteo; Corsini, Massimiliano; Pellacini, Fabio; Scopigno, Roberto; B. Levy, X. Tong, and K. Yin
    In this paper, we present EnvyDepth, an interface for recovering local illumination from a single HDR environment map. In EnvyDepth, the user quickly indicates strokes to mark regions of the environment map that should be grouped together in a single geometric primitive. From these annotated strokes, EnvyDepth uses edit propagation to create a detailed collection of virtual point lights that reproduce both the local and the distant lighting effects in the original scene. When compared to the sole use of the distant illumination, the added spatial information better reproduces a variety of local effects such as shadows, highlights and caustics. Without the effort needed to create precise scene reconstructions, EnvyDepth annotations take only tens of seconds to produce a plausible lighting without visible artifacts. This is easy to obtain even in the case of complex scenes, both indoors and outdoors. The generated lighting environments work well in a production pipeline since they are efficient to use and able to produce accurate renderings.
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    Efficient Shadow Removal Using Subregion Matching Illumination Transfer
    (The Eurographics Association and Blackwell Publishing Ltd., 2013) Xiao, Chunxia; Xiao, Donglin; Zhang, Ling; Chen, Lin; B. Levy, X. Tong, and K. Yin
    This paper proposes a new shadow removal approach for input single natural image by using subregion matching illumination transfer. We first propose an effective and automatic shadow detection algorithm incorporating global successive thresholding scheme and local boundary refinement. Then we present a novel shadow removal algorithm by performing illumination transfer on the matched subregion pairs between the shadow regions and non-shadow regions, and this method can process complex images with different kinds of shadowed texture regions and illumination conditions. In addition, we develop an efficient shadow boundary processing method by using alpha matte interpolation, which produces seamless transition between the shadow and non-shadow regions. Experimental results demonstrate the capabilities of our algorithm in both the shadow removal quality and performance.