• Proceedings of the KIEE Conference
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• 2001.07e
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• pp.103-107
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• 2001

In this paper, we have developed a new Force-Display system using wire-tension method. The proposed system is based on the HIR Lab Haptic Rendering library, which calculates the real position and renders the reflecting force data to device rapidly. The system is composed of device based tendon-driven method, controller and Haptic rendering library. The developed system will be used on constructing the dynamical virtual environment. To show the efficiency of our system, we designed simulation program which can display the moving force (attaching, grabbing, rotating) on two virtual point. As the result of the experiment, our proposed system shows much higher resolution and stability than any others.

• Journal of Korea Multimedia Society
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• v.11 no.4
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• pp.554-565
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• 2008

The French neo-impressionist painter, George Seurat, introduced pointillism under the theory that the individual pigments of colors on the canvas are reconstructed on the human retina. Pointillism is a painting technique in which many small brush strokes are combined to form a picture in the canvas. When such a painting is seen from a far, the individual stroke color are unnoticeable and they are seen as intermixed colors. This is called juxtaposed color mixture. In this paper, we present a painterly rendering method for generating the pointillism images. For expressing countless separate dots which shown in the pointillism works, we propose a hierarchical points structure using Wang The method. Also a user defined palette is constructed based on the usage that Neo-Impressionist painter works on his palette. Lastly, based on this, a probability algorithm will be introduced, which divides the colors in the image(sampled by hierarchical point structure) into juxtaposed colors. A hierarchical points set which undergone juxtaposed color division algorithm is converted into brush strokes.

• Journal of Korea Multimedia Society
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• v.17 no.7
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• pp.906-914
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• 2014

There are many studies to create realistic paint effects and the research area still has attracted attention in these days. However, the consideration for the characteristics of the real paint effects from the point of viewers is not enough. In this paper, we extract the important paint features and survey the importance values. Based on the survey results, we suggest a new paint system. The paint system utilizes the paint simulation that reflects viscoelasticity and mixing suggested by You et al. (2013) and proposes the paint rendering method that represents the details of a paint, a solvent, and pigments. We survey the quality of our results and prove that our paint system is superior to the previous studies.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1997.06a
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• pp.125-130
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• 1997

In this paper we present an algorithm to generate new views of a scene, starting with images from weakly calibrated cameras. Errors in 3D scene reconstruction usually gets reflected in the quality of the new scene generated, so we seek a direct method for reprojection. In this paper, we use the knowledge of dense point matches and their affine coordinate values to estimate the corresponding affine coordinate values in the new scene. We borrow ideas from the object recognition literature, and extend them significantly to solve the problem of reprojection. Unlike the epipolar line intersection algorithms for reprojection which requires at least eight matched points across three images, we need only five matched points. The theory of reprojection is used with hardware based rendering to achieve fast rendering. We demonstrate our results of novel view generation from stereopairs for arbitrary locations of the virtual camera.

• Proceedings of the KIEE Conference
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• 2001.07d
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• pp.2818-2820
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• 2001

This paper presents the method of 3D reconstruction of the depth information from the endoscopic stereo scopic images. After camera modeling to find camera parameters, we performed feature-point based stereo matching to find depth information. Acquired some depth information is finally 3D reconstructed using the NURBS(Non Uniform Rational B-Spline) algorithm. The final result image is helpful for the understanding of depth information visually.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.10
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• pp.2663-2678
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• 2012

Due to sharp depth transition, big holes may be found in the novel view that is synthesized by depth-image-based rendering (DIBR). A hole-filling method based on disparity map is proposed. One important aspect of the method is that the disparity map of destination image is used for hole-filling, instead of the depth image of reference image. Firstly, the big hole detection based on disparity map is conducted, and the start point and the end point of the hole are recorded. Then foreground pixels and background pixels are distinguished for hole-dilating according to disparity map, so that areas with matching errors can be determined and eliminated. In addition, parallaxes of pixels in the area with holes and matching errors are changed to new values. Finally, holes are filled with background pixels from reference image according to these new parallaxes. Experimental results show that the quality of the new view after hole-filling is quite well; and geometric distortions are avoided in destination image, in contrast to the virtual view generated by depth-smoothing methods and image inpainting methods. Moreover, this method is easy for hardware implementation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.1
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• pp.127-135
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• 2015

In this research, we conducted an experiment on evaluating the extending depth information method and surface reconstruction method and the interaction of these two methods in order to enhance the final intermediate view images, which are acquired using DIBR (Depth-Image-Based Rendering) method. We evaluated the experimental control groups using the Microsoft's "Ballet" and "Break Dancer" data sets with three different hole-filling algorithms. The result revealed that the quality was improved the most by applying both extending depth information and surface reconstruction method as compared to the previous point clouds only. In addition, it found that the quality of the intermediate images was improved vastly by only applying extending depth information when using no hole-filling algorithm.

• International Journal of CAD/CAM
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• v.6 no.1
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• pp.139-148
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• 2006

Catmull-Clark subdivision scheme provides a powerful method for building smooth and complex surfaces. But the number of faces in the uniformly refined meshes increases exponentially with respect to subdivision depth. Adaptive tessellation reduces the number of faces needed to yield a smooth approximation to the limit surface and, consequently, makes the rendering process more efficient. In this paper, we present a new adaptive tessellation method for general Catmull-Clark subdivision surfaces. Different from previous control mesh refinement based approaches, which generate approximate meshes that usually do not interpolate the limit surface, the new method is based on direct evaluation of the limit surface to generate an inscribed polyhedron of the limit surface. With explicit evaluation of general Catmull-Clark subdivision surfaces becoming available, the new adaptive tessellation method can precisely measure error for every point of the limit surface. Hence, it has complete control of the accuracy of the tessellation result. Cracks are avoided by using a recursive color marking process to ensure that adjacent patches or subpatches use the same limit surface points in the construction of the shared boundary. The new method performs limit surface evaluation only at points that are needed for the final rendering process. Therefore it is very fast and memory efficient. The new method is presented for the general Catmull-Clark subdivision scheme. But it can be used for any subdivision scheme that has an explicit evaluation method for its limit surface.

• Journal of the Korea Computer Graphics Society
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• v.16 no.3
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• pp.1-10
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• 2010

In this paper, we propose a novel noiseless method of BRDF rendering on a GPU in real-time. Illumination at a surface point is formulated as an integral of BRDF producted with incident radiance over the hemi-sphere domain. The most popular method to compute the integral is the Monte Carlo method, which needs a large number of samples to achieve good image quality. But, it leads to increase of rendering time. Otherwise, a small number of sample points cause serious image noise. The main contribution of our work is a new importance sampling scheme producing a set of incoming ray samples varying continuously with respect to the eye ray. An incoming ray is importance-based sampled at different latitude angles of the eye ray, and then the ray samples are linearly connected to form a curve, called a thread. These threads give continuously moving incident rays for eye ray change, so they do not make image noise. Since even a small number of threads can achieve a plausible quality and also can be precomputed before rendering, they enable real-time BRDF rendering on the GPU.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.181.5-181
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• 2001

This paper presents the method of 3D reconstruction of the depth information from the endoscopic stereo scopic images. After camera modeling to find camera parameters, we performed feature-point based stereo matching to find depth information. Acquired some depth information is finally 3D reconstructed using the NURBS(Non Uniform Rational B-Spline) algorithm. The final result image is helpful for the understanding of depth information visually.