• Title/Summary/Keyword: 법선벡터

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Normal Calculation Using GPU in Point Rendering (점 렌더링에서 GPU를 이용한 법선 벡터 계산)

  • 조광현;권구주;신병석
    • Proceedings of the Korean Information Science Society Conference
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    • pp.634-636
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    • 2004
  • 3차원 공간상에 분포되어 있는 정들로부터 기하정보를 재구성하여 렌더링 할 때 법선 벡터가 필요하다. 이 점들은 서로간의 연결성 정보가 없고 법선 벡터가 없기 때문에 음영 효과를 표현 할 수 없다. 본 논문에서는 점들의 연결성 정보를 추정하여 법선 벡터를 구하는 과정에서 GPU를 사용하는 방법을 제안한다 GPU로 법선 벡터를 계산할 경우 CPU의 부하가 줄게 되고 계산 시간도 감소된다 이 방법을 점 렌더링에 적용하여 법선 벡터를 신속하게 계산하고 가시성 검사와 음영처리를 효과적으로 할 수 있도록 한다.

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Tessellation-independent Approximation of Normal Vectors (Tessellation에 독립적인 법선 벡터 근사에 대한 연구)

  • Ahn, Jaewoo;Kim, Woongsoon
    • Journal of the Korea Computer Graphics Society
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    • v.4 no.2
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    • pp.29-32
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    • 1998
  • When rendering polyhedral models, normal vectors at polygon vertices are necessary for smooth shading. The most commonly used technique of approximating a vertex normal vector by averaging normal vectors of faces around the vertex yields, however, different results on different tessellations Further, continuous deformation of models may cause abrupt discontinuous changes in normal vector directions. In this paper, a variation of the above technique is proposed to avoid these problems. Specifically, it uses a weighted average of normal vectors of faces around the vertex, where the weight of a face being the angular span of the two edges incident on the vertex.

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Camera Exterior Orientation for Image Registration onto 3D Data (3차원 데이터상에 영상등록을 위한 카메라 외부표정 계산)

  • Chon, Jae-Choon;Ding, Min;Shankar, Sastry
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.25 no.5
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    • pp.375-381
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    • 2007
  • A novel method to register images onto 3D data, such as 3D point cloud, 3D vectors, and 3D surfaces, is proposed. The proposed method estimates the exterior orientation of a camera with respective to the 3D data though fitting pairs of the normal vectors of two planes passing a focal point and 2D and 3D lines extracted from an image and the 3D data, respectively. The fitting condition is that the angle between each pair of the normal vectors has to be zero. This condition can be represented as a numerical formula using the inner product of the normal vectors. This paper demonstrates the proposed method can estimate the exterior orientation for the image registration as simulation tests.

Indoor environment recognition in depth image using domain knowledge (깊이 영상에서 도메인지식을 이용한 실내 환경 인식)

  • Kim, Su-Kyung;Choi, Hyung-Il
    • Proceedings of the Korean Society of Computer Information Conference
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    • pp.319-322
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    • 2014
  • 본 논문에서는 깊이 카메라로 받아들인 입력 영상의 3차원 공간 내에서 벽면을 분리하는 방법을 제안한다. 본 논문에서 제안하는 벽면이 구분된 영상은 벽면에 프로젝터를 투사하는 등의 3차원 공간 활용에 용이하다. 입력 영상에서의 좌표 점을 이용하여 법선 벡터를 검출하고, 법선 벡터를 통해 평면을 분리한다. 분리된 평면들을 실내 환경에서 알 수 있는 도메인 지식들에 기반하여 벽면으로 구분 된다.

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Virtual Make-up System Using Light and Normal Map Approximation (조명 및 법선벡터 지도 추정을 이용한 사실적인 가상 화장 시스템)

  • Yang, Myung Hyun;Shin, Hyun Joon
    • Journal of the Korea Computer Graphics Society
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    • v.21 no.3
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    • pp.55-61
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    • 2015
  • In this paper, we introduce a method to synthesize realistic make-up effects on input images efficiently. In particular, we focus on shading on the make-up effects due to the lighting and face curvature. By doing this, we can synthesize a wider range of effects realistically than the previous methods. To do this, the information about lighting information together with the normal vectors on all pixels over the face region in the input image. Since the previous methods that compute lighting information and normal vectors require relatively heavy computation cost, we introduce an approach to approximate lighting information using cascade pose regression process and normal vectors by transforming, rendering, and warping a standard 3D face model. The proposed method consumes much less computation time than the previous methods. In our experiment, we show the proposed approximation technique can produce naturally looking virtual make-up effects.

Vertex Normal Computation using Conformal Mapping and Mean Value Coordinates (등각사상과 평균값좌표계를 이용한 정점 법선벡터 계산법)

  • Kim, Hyoung-Seok B.;Kim, Ho-Sook
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.3
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    • pp.451-457
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    • 2009
  • Most of objects in computer graphics may be represented by a form of mesh. The exact computation of vertex normal vectors is essential for user to apply a variety of geometric operations to the mesh and get more realistic rendering results. Most of the previous algorithms used a weight which resembles a local geometric property of a vertex of a mesh such as the interior angle, the area, and so on. In this paper, we propose an efficient algorithm for computing the normal vector of a vertex in meshes. Our method uses the conformal mapping which resembles synthetically the local geometric properties, and the mean value coordinates which may smoothly represent a relationship with the adjacent vertices. It may be confirmed by experiment that the normal vector of our algorithm is more exact than that of the previous methods.

Photometry Data Compression for Three-dimensional Mesh Models Using Connectivity and Geometry Information (연결성 정보와 기하학 정보를 이용한 삼차원 메쉬 모델의 광학성 정보 압축 방법)

  • Yoon, Young-Suk;Ho, Yo-Sung
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.45 no.3
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    • pp.160-174
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    • 2008
  • In this paper, we propose new coding techniques for photometry data of three-dimensional(3-D) mesh models. We make a good use of geometry and connectivity information to improve coding efficiency of color, normal vector, and texture data. First of all, we determine the coding order of photometry data exploiting connectivity information. Then, we exploit the obtained geometry information of neighboring vortices through the previous process to predict the photometry data. For color coding, the predicted color of the current vertex is computed by a weighted sum of colors for adjacent vortices considering geometrical characteristics between the current vortex and the adjacent vortices at the geometry predictor. For normal vector coding, the normal vector of the current vertex is equal to one of the optimal plane produced by the optimal plane generator with distance equalizer owing to the property of an isosceles triangle. For texture coding, our proposed method removes discontinuity in the texture coordinates and reallocates texture image segments according to the coding order. Simulation results show that the proposed compression schemes provide improved performance over previous works for various 3-D mesh models.

Indoor environment recognition based on depth image (깊이 영상 기반 실내 공간 인식)

  • Kim, Su-Kyung;Choi, Hyung-Il
    • Journal of the Korea Society of Computer and Information
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    • v.19 no.11
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    • pp.53-61
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    • 2014
  • In this paper, we propose a method using an image received by the depth camera in order to separate the wall in a three-dimensional space indoor environment. Results of the paper may be used to provide valuable information on the three-dimensional space. For example, they may be used to recognize the indoor space, to detect adjacent objects, or to project a projector on the wall. The proposed method first detects a normal vector at each point by using the three dimensional coordinates of points. The normal vectors are then clustered into several groups according to similarity. The RANSAC algorithm is applied to separate out planes. The domain knowledge helps to determine the wall among planes in an indoor environment. This paper concludes with experimental results that show performance of the proposed method in various experimental environment.

Optical Multi-Normal Vector Based Iridescence BRDF Compression Method (광학적 다중 법선 벡터 기반 훈색(暈色)현상 BRDF 압축 기법)

  • Ryu, Sae-Woon;Lee, Sang-Hwa;Park, Jong-Il
    • Journal of KIISE:Computer Systems and Theory
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    • v.37 no.3
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    • pp.184-193
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    • 2010
  • This paper proposes a biological iridescence BRDF(Bidirectional Reflectance Distribution Function) compression and rendering method. In the graphics technology, iridescence sometimes is named structure colors. The main features of these symptoms are shown transform of color and brightness by varying viewpoint. Graphics technology to render this is the BRDF technology. The BRDF methods enable realistic representation of varying view direction, but it requires a lot of computing power because of large data. In this paper, we obtain reflection map from iridescence BRDF, analyze color of reflection map and propose representation method by several colorfully concentric circle. The one concentric circle represents beam width of reflection ray by one normal vector. In this paper, we synthesize rough concentric by using several virtually optical normal vectors. And we obtain spectrum information from concentric circles passing through the center point. The proposed method enables IBR(image based rendering) technique which results is realistic illuminance and spectrum distribution by one texture from reduced BRDF data within spectrum.