• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2008.04a
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• pp.435-438
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• 2008

본 논문에서는 애니메이션을 위해서 얼굴의 특징표현(Action Units)의 조합하는 방법으로 얼굴 모델링을 하기 위한 3D대응점(3D dense correspondence)을 찾는 방법을 제시한다. AUs는 표정, 감정, 발음을 나타내는 얼굴의 특징표현으로 통계적 방법인 PCA (Principle Component Analysis)를 이용하여 만들 수 있다. 이를 위해서는 우선 3D 모델상의 대응점을 찾는 것이 필수이다. 2D에서 얼굴의 주요 특징 점은 다양한 알고리즘을 이용하여 찾을 수 있지만 그것만으로 3D상의 얼굴 모델을 표현하기에는 적합하지 않다. 본 논문에서는 3D 얼굴 모델의 대응점을 찾기 위해 원기둥 좌표계 (Cylinderical Coordinates System)을 이용하여 3D 모델을 2D로 투사(Projection)시켜서 만든 2D 이미지간의 워핑(Warping) 을 통한 대응점을 찾아 역으로 3D 모델간의 대응점을 찾는다. 이것은 3D 모델 자체를 변환하는 것보다 적은 연산량으로 계산할 수 있고 본래 형상의 변형이 없다는 장점을 가지고 있다.

• Journal of Electrical Engineering and Technology
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• v.9 no.5
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• pp.1762-1773
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• 2014

In this paper, a distributed image coding scheme for multi-view video through an efficient generation of side information is proposed. A distributed video coding technique corrects the errors in the side information, which is generated with the original image, by using the channel coding technique at the decoder. Therefore, the more correct the generated side information is, the better the performance of distributed video coding. The proposed technique is to apply the distributed video coding schemes to the image coding for multi-view video. It generates side information by selectively and efficiently using both 3-dimensional warping based on the depth map with spatially adjacent frames and motion-compensated temporal interpolation with temporally adjacent frames. In this scheme the difference between the adjacent frames, the sizes of the motion vectors for the adjacent blocks, and the edge information are used as the selection criteria. From the experiments, it was observed that the quality of the side information generated by the proposed technique was improved by the average peak signal-to-noise ratio of 0.97dB than the one by motion-compensated temporal interpolation or 3-dimensional warping. The result from analyzing the rate-distortion curves revealed that the proposed scheme could reduce the bit-rate by 8.01% on average at the same peak signal-to-noise ratio value, compared to previous work.

• Journal of Broadcast Engineering
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• v.20 no.3
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• pp.414-420
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• 2015

The quality of depth images is important in the 3D video system to represent complete 3D contents. However, the original depth image from a depth camera has a low resolution and a flickering problem which shows vibrating depth values in terms of temporal meaning. This problem causes an uncomfortable feeling when we look 3D contents. In order to solve a low resolution problem, we employ 3D warping and a depth weighted joint bilateral filter. A temporal mean filter can be applied to solve the flickering problem while we encounter a residual spectrum problem in the depth image. Thus, after classifying foreground andbackground regions, we use an upsampled depth image for a foreground region and temporal mean image for background region.Test results shows that the proposed method generates a time consistent depth video with a high resolution.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.10
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• pp.2112-2122
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• 1997

This paper presents a new video codec which is based on 2-D triangular mesh-based motion compensation and two step grid point motion estimation. With this approach the efficiency of compression and the quality of reconstructed images are improved. The compensation of motion for each triangular patch is performed by image warping using motion vectors at the grid points. The prediction error coding and the rate control meet MPEG-4 VM 3.0 specification. The experimental results show that the codec system proposed is simple in complexity and moreover, the quality of decoded images is improved.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.5169-5175
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• 2013

We present a framework for 3D hand gesture design and modeling. We adapted two different pattern matching techniques, Dynamic Time Warping (DTW) and Hidden Markov Models (HMMs), to support the registration and evaluation of 3D hand gestures as well as their recognition. One key ingredient of our framework is a concept for the convenient gesture design and registration using HMMs. DTW is used to recognize hand gestures with a limited training data, and evaluate how the performed gesture is similar to its template gesture. We facilitate the use of visual sensors and body sensors for capturing both locative and inertial gesture information. In our experimental evaluation, we designed 18 example hand gestures and analyzed the performance of recognition methods and gesture features under various conditions. We discuss the variability between users in gesture performance.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.315-318
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• 2005

Vlasov's hypothesis provides a way to solve the torsional problem with warping torsion of double T-beam section. Not only the warping torsion of the gross section of double T-beam but the torsional resistances of PS tendons and reinforcements have to be considered together in the analysis in which the latter is the restoring roles provided by the upward and downward force components in a geometrical symmetric configuration. It means that the torsional resistances of PS tendons and reinforcements, usually ignored, store the strain energies due to up-downward geometrical changes. Space frame element with 7-degrees of freedom are used for the finite element approximation of the real behaviors. Bimoments and angles of twist obtained from the proposed method show good agreements with those of 3-D. finite element analysis and analytical analysis

• Proceedings of the Korea Contents Association Conference
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• 2011.05a
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• pp.51-52
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• 2011

We introduce a novel complete framework for contructing realistic facial animations given just one facial photo as an input in this paper. Our approach is carried on in 2D photo spacem not 3D space. Moreover, we utilize computer vision-based technique (digital matting) as well as conventional image processing methods (image warping and texture synthesis) for expressing more realistic facial animations. Simulated results show that our scheme produces high quality facial animations very efficiently.

• Journal of Korea Game Society
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• v.7 no.2
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• pp.11-20
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• 2007

This paper proposes a real-time simulation technique for thin shells undergoing large deformation. Shells are thin objects such as leaves and papers that can be abstracted as 2D structures. Development of a satisfactory physical model that runs in real-time but produces visually convincing animation of thin shells has been remaining a challenge in computer graphics. Rather than resorting to shell theory which involves the most complex formulations in continuum mechanics, we adopt the energy functions from the discrete shells proposed by Grinspun et al. For real-time integration of the governing equation, we develop a modal warping technique for shells. This new simulation framework results from making extensions to the original modal warping technique which was developed for the simulation of 3D solids. We report experimental results, which show that the proposed method runs in real-time even for large meshes, and that it can simulate large bending and/or twisting deformations with acceptable realism.

• Proceedings of the KSR Conference
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• 2003.05a
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• pp.382-387
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• 2003

This research has investigated structural characteristics of curved two girder bridges proposed for AGT system and analyzed the results of the structural analysis of three different modelings for 3 span continuous bridge, each modeled in grillage modeling, simplified 3D modeling, and detailed 3D modeling respectively. The grillage modeling appeared to be somewhat underestimated in deflection and overestimated in rotation with respect to 3D modelings. Also, it is impossible to make a detailed examination of local buckling and details of cross beams, etc. The point that warping effect cannot be considered may cause the structural analysis unsafe, accordingly the structural analysis of curved two girder bridges should be done with 3D modelings.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.620-624
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• 2009

In this paper, we present a new camera system combining a high-quality 3-D scanner and hybrid camera system to generate a multiview video-plus-depth. In order to get the 3-D video using the hybrid camera system and 3-D scanner, we first obtain depth information for background region from the 3-D scanner. Then, we get the depth map for foreground area from the hybrid camera system. Initial depths of each view image are estimated by performing 3-D warping with the depth information. Thereafter, multiview depth estimation using the initial depths is carried out to get each view initial disparity map. We correct the initial disparity map using a belief propagation algorithm so that we can generate the high-quality multiview disparity map. Finally, we refine depths of the foreground boundary using extracted edge information. Experimental results show that the proposed depth maps generation method produces a 3-D video with more accurate multiview depths and supports more natural 3-D views than the previous works.