• Journal of the Korea Institute of Military Science and Technology
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• v.16 no.5
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• pp.583-589
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• 2013

In this paper, we proposed a system that efficiently provides support maps which includes the grid based terrain analysis information. To do this, we use the FDB which is defined as a GIS database that contains features with attributes attached to the features. The FDB is composed of a number of features and feature classes. In order to create support maps, it is necessary to classify feature classes that are associated with each support map and to search them in a grid map. The proposed system use a ontology model to classify semantically feature classes and the quad-tree data structure to find them in a grid map quickly. Therefore, our system is expected to be utilized for global path planning of UGV. In this paper, we show the possibility through an experimental implementation.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.07a
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• pp.56-57
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• 2015

근래 3D산업의 발전으로 디지털 홀로그램 기술이 부각되고 있다. 본 논문에서는 디지털 홀로그램 영상을 쿼드트리형식으로 Fresnelet 변환을 통한 양자화기를 구현하기위해 특징 및 중요도를 분석하는 방식에 대해 제안한다. 디지털 홀로그램 영상을 Fresnelet 변환을 수행한 뒤 부대역 별로 평균에너지에 따른 에너지 분포의 순위를 정하였고, 크기에 따른 히스토그램의 결과를 이용해 향후 디지털 홀로그램 압축 및 전송 기법에 적용할 수 있는 것을 확인 하였다.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.5
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• pp.593-599
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• 1999

A mobile robot in FMS environment should be able to nevigate itself. Therefore, path planning is necessary for the mobile robot to perform its tasks without being lost. Path planning using a network model gives oprimal paths to every pair of nodes but building this model demands accurate information of environments. In this paper, a method to build a network model using sonar sensors is presented. The main idea is to build a quad tree model by using sonar sensors and convert the model to a network model for path planning. The new method has been implemented on a mobile robot. Experimental results show that the mobile robot constructs an accurate network model using inaccurate sonar data.

• Journal of the Korea Computer Graphics Society
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• v.8 no.1
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• pp.21-28
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• 2002

This paper presents a brush stroke direction creation method to distill painterly expressions from picture images. In actual paintings, each brush stroke has the same directionality in one segmented area. but directionality changes in the area of image border edges. This study employed the following methods to implement the directionality of the brush stroke area by: (1) detecting edge in input images, (2) region splitting and merging based on quad-tree division method, and (3) composing a direction map to create brush strokes with the same directionality in the segmented area. The results of the implementation enabled the simulation of the directionality of the stroke area shown in actual paintings.

• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.334-337
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• 1987

An algorithm is presented which computes the perimeter of regions in images represented by BF( breadth first) linear quadtree. In order to compute the perimeter, we determine adjacent neighbor nodes in the horizontal and vertical directions. It is the method which directly find the associated nodes in order to know whether it exists in BF linear quad tree or not. Average execution time of the algorithm is proportional to the number of black nodes in the quadtree.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.11a
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• pp.193-196
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• 2015

조건부대체 알고리즘(CRA: Conditional Replenishment Algorithm)은 좌우 영상의 해상도가 서로 다른 융합형 3DTV 서비스 환경에서 입체영상의 화질을 개선하기 위해 제안된 기법이다. 조건부대체 알고리즘에서는 비용함수를 도입하여 quad-tree 구조를 가지는 가변크기의 처리단위 (PU: Processing Unit)의 최적 모드를 결정하는데, 본 논문에서는 관심 PU 의 모드를 결정하는 단계에서 주변 PU 들의 모드를 함께 고려함으로써 모드가 고립되는 현상을 방지하는 방법을 제안한다. 제안 방법을 통해 기존의 CRA 의 결과로 발생 가능한 특정 PU의 두드러짐 현상을 제거할 수 있기 때문에 합성된 입체 영상의 주관적 화질이 향상된다.

• Spatial Information Research
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• v.3 no.1
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• pp.19-27
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• 1995

In this paper, a semi-automated mapping system, which can produ¬ce digital maps by using information acquired from pre-processing procedure, was introduced. To get a binary edge image, which is very important in vectori¬zation process, we applied adaptive smoothing and connection preserving thresho¬Iding algorithm. In mapper program, binary images are converted to vectors and for in-core data structure, extended PR quad tree was used. These procedures are dispatched to personal computers and workstations and through network resource sharing, the whole process was unified and simplified.

• Korean Journal of Computational Design and Engineering
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• v.11 no.6
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• pp.403-411
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• 2006

NURBS surfaces have been widely used in engineering design since it can create a smooth surface using minimal numbers of data. But deformation of the surfaces is quite difficult especially for the detailed modification. Also, NURBS surface deformation processes need many inputs, and it is not easy to be implemented in 3D virtual system. In this paper, both the surface trimming and multi-resolution surface are used for the detailed sculpting including sharp edges of NURBS surface. QuadTree is used to separate cleanly the target surface with the surface for sculpting effect. Simple user strokes are also used for the sculpting target curves and GOMS(Goals, Operators, Methods, Selection Rules) model is applied to verify the efficiency of the proposed sculpting process.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.11a
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• pp.75-78
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• 2013

최근 3D의 발전으로 다음 세대의 3D 기술로 디지털 홀로그램을 지목하고 있다. 본 논문에서는 프레넬릿 변환을 이용하여 디지털 홀로그램 압축을 위한 효과적인 양자화 방법에 대하여 제안하였다. 효과적인 양자화 방법을 위해 각각의 부대역의 특성에 고려하여 우선순위를 정하고 양자화를 적용하였다. 또한 PSNR을 높이고자 예외 인덱스를 적용하였다. 그 결과 2dB 정도 높아지는 것을 확인할 수 있었다. 실험결과에서는 최소 약 6:1부터 최대 약 181:1까지 압축을 수행하였고, PSNR을 이용하여 압축된 영상에 대하여 수치적인 결과를 분석하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.04a
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• pp.163-166
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• 2012

OpenMP를 이용할 경우 컴파일러 디렉티브의 삽입으로 병렬화가 가능하다. 본 논문은 쿼드 트리를 이용한 데이터베이스 검색 프로그램을 OpenMP로 병렬화하여 실험을 진행한다. 실험을 통해 논리코어의 개수와 쓰레드 개수에 따른 상관관계가 적다는 것을 알 수 있다. 또한 쓰레드 개수 증가에 따른 오버헤드 발생이 성능에 영향을 준다는 사실을 알 수 있다. 쿼드 트리 자료구조를 이용한 데이터베이스 검색 프로그램을 OpenMP를 이용해 병렬화할 경우 논리적 코어의 개수가 8개, 쓰레드 개수가 16개일 경우에 1.8배의 최대의 성능향상을 이룬다.