• Proceedings of the Korean Information Science Society Conference
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• 2000.10b
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• pp.484-486
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• 2000

일러스트레이션은 물체를 표현하는 최소한의 특징만을 가지고 사물을 표현하는 방법이다. 이를 자동화한 많은 연구들은 주로 많은 스트록을 이용하여 실제와 유사한 일러스트레이션 결과를 생성하고자 하였다. 본 연구는 물체의 특징만을 표현할 수 있는 적은 스트록을 이용하여 일러스트레이션을 생성하는데 목적을 둔다. 이를 위해 우리는 이전 연구[1]에서 간단히 추출된 경계선과 두 가지 스트록 모핑기법을 제시하였다. 본 논문에서는 물체의 특징을 표현하기 위해 유용한 경계선 추출 방법을 제시한다. 정확한 경계선의 추출은 스트록과 더불어 최종 일러스트레이션 결과에 많은 영향을 미친다. 경계선 추출 방법과 이전 논문의 스트록 모핑 방법을 이용한 일러스트레이션 결과는 본 논문의 실험결과로 주어졌다.

• Journal of KIISE:Software and Applications
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• v.28 no.9
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• pp.649-661
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• 2001

While the conventional edge detection can be considered as the problem of determining the existence of edges at certain locations, the fuzzy edge modeling can be considered as the problem of determining the membership values of edges. Thus, if the location of an edge is unclear, or if the intensity function is different from the ideal edge model, the degree of edgeness at the location is represented as a fuzzy membership value. Using the concept of fuzzy edgeness, an automatic smoothing parameter evaluation and selection method for a conventional edge detector is proposed. This evaluation method uses the fuzzy edge modeling, and can analyze the effect of smoothing parameter to determine an optimal parameter for a given image. By using the selected parameter we can detect least ambiguous edges of a detection method for an image. The effectiveness of the parameter evaluation method is analyzed and demonstrated using a set of synthetic and real images.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.10
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• pp.1305-1313
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• 2013

In this study, a method to apply feature-based simplification to boundary representation models is proposed. For feature-based simplification, a volume decomposition tree is created from a boundary representation model. The volume decomposition tree is represented by regularized Boolean operations of additive volumes, subtractive volumes, and fillet/round/chamfer volumes, and it is generated by stepwise volume decomposition, which consists of fillet/round/chamfer decomposition, wrap-around decomposition, volume split decomposition, and cell-based decomposition. After the volume decomposition tree is transformed to an infix expression, the CAD model can be simplified by reordering the volumes. To verify the proposed method, a prototype system was implemented, and experiments on test cases were conducted. From the results of the experiments, it is verified that the proposed method is useful for simplifying CAD models based on boundary representation.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2006.04a
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• pp.445-450
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• 2006

지적정보가 미래에 펼쳐질 유비쿼터스 환경에서의 기반 자료라는 측면에서 본다면, 무한한 부가가치를 창출하기 위해서는 새로운 위치 표현, 새로운 좌표 체계 그리고 좌표 관리의 현대화는 필수적이다. 따라서 유비쿼터스 시대를 대비한 지적정보 표현 방안에 대하여 연구를 진행하였다. 본 연구에서는 유비쿼터스 환경하에서의 지적필지경계 표현 및 관리를 위하여 필지경계를 현지에서 확인하고 복원할 수 있는 방안을 고찰하였다. 또한 필지별 경계 좌표 표시 및 필지정보 현장 보관 방법을 제시하기 위한 연구도 진행하였다. 그리고 제안한 새로운 좌표계 타당성에 대하여 분석을 진행하였다. 그리고 미래의 지적관리가 더욱 효율적이고 지능화된 관리를 진행할 수 있도록 유비쿼터스 기반 기술인 RFID를 지적필지경계 관리에 적용하는 방안을 제시하였다.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.10
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• pp.777-788
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• 2006

This paper describes a displacement mapping technique which represents protruded shapes on the surface of an object. Previous approaches for image-based displacement mapping can represent only shapes depressed from the polygon surface. The proposed technique can represent shapes protruded from the underlying surface in real-time. Two auxiliary surfaces which are perpendicular to the underlying surface are added along the boundary of the polygon surface, in order to represent the pixels which overflow over the boundary of the polygon surface. The proposed approach can represent accurate silhouette of protruded shape. It can represent not only smooth displacement of protruded shape, but also abrupt displacement such as perpendicular protrusion by means of adding the supplementary texture information to the steep surface of protruded shape. By per-pixel instructions on the programmable GPU this approach can be executed in real-time. It provides an effective solution for the representation of protruded shape such as high-rise buildings on the ground.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.2
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• pp.151-157
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• 1990

This paper presents a method for rapid wire frame drawing of the 3D objects represented by the CSG scheme. When the two CSG trees are combined into one, the intersection parts of the polygons constituting the object corresponds to each subtree are computed, and the boundary representation of the combined object is obtained according to the given combinational operator and stored in the root node. The boundary representation in the root node is used in the wireframe drawing of the object and later computation of boundary representation. Bezier surface is taken as one of the primitive object the scan-line algorithm is used, which subdivides each scan-line into the spans where no polygon is intersected, and renders each span with the CSG representation of the object.

• Proceedings of the Korea Multimedia Society Conference
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• 2001.11a
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• pp.165-169
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• 2001

본 논문에서는 텍스쳐가 포함된 칼라 영상으로부터 텍스쳐에 무관하게 영역을 분할할 수 있는 방법을 개발하였다. 빠른 처리를 위해 영상을 블록 단위로 쪼개고 블록의 경계 성분값(H)을 계산하여 영역 분할에 이용할 수 있도록 하였다. M값은 객체의 경계에서는 높은 경계 강도를 갖지만 영역 내부나 텍스쳐 경계에서는 상대적으로 낮은 경계 강도를 갖도록 정의되었다 영상 분할을 위해 M값으로 표현된 M영상으로부터 Watershed를 이용해 경계 위치를 결정하고 닫혀진 형태로 경계가 표현될 수 있도록 하였다. 그런데 Watershed 방법은 과잉 분할 결과를 초래하므로 인접 영역 사이의 공유 경계에 대한 강도와 영역 내부의 칼라 분포 특성을 이용하여 영역을 병합함으로써 객체 경계처럼 중요한 변화가 발생되는 영역 단위의 최종 영상 분할된 결과를 얻을 수 있도록 하였다. 본 논문에서 제안한 방법은 MPEG4나 내용기반검색을 위한 영역분할에 유용하게 적용될 수 있을 것이다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.453-456
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• 2003

Spatial database systems achieve filtering steps with MBR(Minimum founding Rectangle) for efficient query processing, and then carry out refinement steps for candidate objects. While most operations require fast execution of filtering, it is necessary to increase the filtering rates and reduce the number of refinement steps in the low computing powered devices. The compact representation method is also needed in the mobile devices with low storage capacity. The paper proposes various approximation methods for efficient spatial operations in the multiplatform environments. This paper also designs a compression technique for MBR, which occupies almost 80% of index data in the two dimensional case. We also analyze the advantages and drawbacks of each method in terms of space utilization, filtering efficiency and speed.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.11a
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• pp.298-301
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• 2011

Edge detection is an base research task in the field of image processing. Edge detection can be regarded as a technique for locating pixels of abrupt gray-level change. So with Gradient method, it can be computed easily. But it can't satisfy human naked eye. so in this paper, new algorithm based on the NLM(Non Local Means) is proposed for good performance for human naked eye.

• Journal of Korea Multimedia Society
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• v.7 no.11
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• pp.1531-1539
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• 2004

In this paper, we propose an efficient method for locating human lips. Based on Point Distribution Model and Principle Component Analysis, a lip shape model is built. Lip boundary model is represented based on the concatenated gray level distribution model. We calculate the distribution of shape parameters using Gaussian mixture. The problem to locate lip is simplified as the minimization problem of matching object function. The Down Hill Simplex Algorithm is used for the minimization with Gaussian Mixture for setting initial condition and refining estimate of lip shape parameter, which can refrain iteration from converging to local minima. The experiments have been performed for many images, and show very encouraging result.