• Journal of Digital Contents Society
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• v.9 no.2
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• pp.305-315
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• 2008

Pre-proposed AHHS(Adaptive Hierarchical Hexagon Search) is a kind of the fast hierarchical block matching algorithm based on the AHS(Adaptive Hexagon Search). It is characterized as keeping the merits of the AHS capable of fast estimating motion vectors and also adaptively reducing the local minima often occurred in the video sequences with higher spatio-temporal motion activity. The objective of this paper is to propose the method effectively extending the horizontal biased pattern and the vertical biased pattern of the AHHS to improve its predictive image quality. In the paper, based on computer simulation results for multiple video sequences with different motion characteristics, the performance of the proposed method was analysed and assessed in terms of the predictive image quality and the computational time. The simulation results indicated that the proposed method was both suitable for (quasi-) stationary and large motion searches. While the proposed method increased the computational load on the process extending the hexagon search patterns, it could improve the predictive image quality so as to cancel out the increase of the computational load.

• Korean Journal of Remote Sensing
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• v.23 no.4
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• pp.297-309
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• 2007

The first Korean geostationary weather satellite, Communications, Oceanography and Meteorology Satellite (COMS) will be launched in 2008. The ground station for COMS needs to perform geometric correction to improve accuracy of satellite image data and to broadcast geometrically corrected images to users within 30 minutes after image acquisition. For such a requirement, we developed automated and fast geometric correction techniques. For this, we generated control points automatically by matching images against coastline data and by applying a robust estimation called RANSAC. We used GSHHS (Global Self-consistent Hierarchical High-resolution Shoreline) shoreline database to construct 211 landmark chips. We detected clouds within the images and applied matching to cloud-free sub images. When matching visible channels, we selected sub images located in day-time. We tested the algorithm with GOES-9 images. Control points were generated by matching channel 1 and channel 2 images of GOES against the 211 landmark chips. The RANSAC correctly removed outliers from being selected as control points. The accuracy of sensor models established using the automated control points were in the range of $1{\sim}2$ pixels. Geometric correction was performed and the performance was visually inspected by projecting coastline onto the geometrically corrected images. The total processing time for matching, RANSAC and geometric correction was around 4 minutes.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1999.11b
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• pp.21-25
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• 1999

Wavelet transform decomposes a video frame into a set of subframes with different resolutions corresponding to different frequency bands. The block size of highest layer subframe is too small to estimate correct motion. To decrease this aperture problem in the approximation frame, multiresolution motion estimation (MRME) using hierarchical block matching is presented in this paper. In the multiresolution motion estimation approach, motion vectors in the subframes are estimated by the motion vectors in the approximation frame and are refined at each subframe. It reduces computational time in motion estimation. It is shown that our MRME approach has a superior performance than traditional MRME approaches.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2007.02a
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• pp.79-82
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• 2007

본 논문은 정합 검증 패턴을 이용한 적응형 계층 육각 탐색의 성능 개선에 관한 것이다. 제안된 방법은 움직임 추정 블록에 시공간적으로 인접한 블록들의 움직임 벡터를 이용하여 움직임 활동도를 정의한 후, 움직임 활동도가 높을 경우 웨이블렛 변환의 다단계 저주파 부영상들로 구성된 피라미드 계층 구조상에서 정합 검증 패턴을 이용한 적응형 계층 육각 탐색을 수행한다. 제안된 방법을 이용할 경우, 정합 검증 패턴을 적용한 검증 과정에서 추가적인 연산량 증가가 초래되지만 이를 상호타협적으로 보상할 수 있는 화질 측면에서의 성능 개선 효과를 기대할 수 있다. 제안된 방법의 타당성과 보편성을 검증하기 위해서로 다른 움직임 특성을 갖는 복수의 영상 시퀀스들을 대상으로 움직임 보상 화질과 수렴시간 측면에서 그 성능을 분석 평가하였다. 컴퓨터 시뮬레이션 결과에 따르면, 제안된 방법은 고속 움직임 탐색이 가능한 적웅형 계층 육각 탐색의 장점을 유지하면서도 움직임 활동도가 높은 영상 시퀀스에서 야기되는 국부 최소 문제를 효과적으로 억제시킴으로써 보상 화질 측면에서 개선된 성능을 제공할 수 있었다.

• Journal of Information Processing Systems
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• v.14 no.2
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• pp.435-447
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• 2018

Fingerprint-based biometric identification is one of the most interesting automatic systems for identifying individuals. Owing to the poor sensing environment and poor quality of skin, biometrics remains a challenging problem. The main contribution of this paper is to propose a new approach to recognizing a person's fingerprint using the fingerprint's local characteristics. The proposed approach introduces the barycenter notion applied to triangles formed by the Delaunay triangulation once the extraction of minutiae is achieved. This ensures the exact location of similar triangles generated by the Delaunay triangulation in the recognition process. The results of an experiment conducted on a challenging public database (i.e., FVC2004) show significant improvement with regard to fingerprint identification compared to simple Delaunay triangulation, and the obtained results are very encouraging.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.28B no.7
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• pp.508-519
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• 1991

A new heuristic two-dimensional symbolic layout compaction approach is developed. After conventional one-dimensional compaction steps, all the components on the critical paths that define the height or width of the given layout are found and rearranged to reduce layout size. During this process, constraints in both x and y directions are considered and pitch-matching of ports for hierarchical compaction can be achieved to reduce the amount of the design data. This approach generated the smallest area for several examples we have tried when compared with other published results. The expected run time can be bouned by OT$_1$, where T$_1$ is the run time of a typical one-dimensional compactor.

• Korean Journal of Computational Design and Engineering
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• v.11 no.3
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• pp.211-222
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• 2006

In collaborative environment, it is necessary that the participants in collaboration should share the same understanding about the semantics of terms. For example, they should know that 'COMPONENT' and 'ITEM' are different word-expressions for the same meaning. In order to handle such problems in information sharing, an information system needs to automatically recognize that the terms have the same semantics. So we develop an algorithm mapping two terms based on their ontological definitions and their similarities. The proposed algorithm consists of four steps: the character matching, the inferencing, the definition comparing and the similarity checking. In the similarity checking step, we consider relation similarity and hierarchical similarity. The algorithm is very primitive, but it shows the possibility of semi-automatic mapping using ontology. In addition, we design a mapping procedure for a mapping system, called SOM (semantic ontology mapper).

• The Transactions of the Korea Information Processing Society
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• v.5 no.7
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• pp.1691-1716
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• 1998

본 논문에서는 계층적 블록매칭 알고리즘(HBMA)을 위한 두 가지 병렬 VLSI 아키텍쳐를 제안한다. HBMA는 계층에 따른 반복수행과 공간 인터폴레이션을 기반으로 수행되며, 이러한 수행 특성은 병렬처리의 장애요소인 데이터 종속성을 내재하고 있다. 제안된 아키텍쳐는 HBMA의 계층간 데이터 종속성을 해결하기 위하여 기본적으로 파이프라인 구조를 채택하고 있으며, HBMA에서 주어진 매개변수에 따라 세 단계의 스테이지로 구성된다. 제안된 아키텍쳐는 입력 프레임 데이터의 흐름을 제어하는 방식에 따라 두 가지 종류로 구분된다. U-Architecture는 단방향 스캔 순서를 따르도록 설계되었으며, B-Architecture는 양방향 스캔 수서를 따르도록 설계되었다. 각 아키텍쳐의 내부 메모리와 인터폴레이션 모듈은 해당 스캔 순서에 따라 동기적으로 동작할 수 있는 구조를 가진다. 성능분석의 결과로서 본 논문에서 제안한 두 가지 아키텍쳐가 모두 방송용 비디오 포맷을 실시간으로 처리할 수 있음을 보이고, HDTV 포맷은 가까운 장래의 VLSI 기술로 실시간 성능을 얻을 수 있음을 보였다. 또한, B-Architecture는 공간 연결성 내부 메모리 구조를 채택함으로써 입력 데이터의 재활용도를 높이고, 이에 따라 Q-Architecture에 비해서 데이터 입출력 핀의 개수를 약 반정도 줄일 수 있는 특성을 보이고 있다.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1994.04a
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• pp.527-534
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• 1994

This paper presents a Bin-Picking method in which robot recognizes the positions and orientations of unoccluded objects at the top of jumbled objects placed in a bin, and picks up the unoccluded objects one by one from the jumble. A method using feasible region, painting, and hierarchical test is introduced for recognizing the unoccluded objects from the jumbled objects. The 3D information is obtained using the bipartite-matching method which finds the least difference of 3D by comparing vertexes of one camera with vertexes of the other camera, then hypothesis and test are done. The working order of unoccluded objects is made based on 3D, position, and orientation information. The robot picks up the unoccluded objects from the jumbled objects according to the working order. This all process continues to the empty bin.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.575-579
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• 1990

This paper describes an algorithm that can efficiently analyze the multichannel ECG signal using the frame. The input is a set of significant features (points) which have been extracted from an original sampled signal by using the split-and-merge algorithm. A signal from each channel can be hierarchical ADN/OR graph on the basis of the priori knowledge for ECG signal. The search mechanisms with some heuristics and the mixed paradigms of data-driven hypothesis formation are used as the major control mechanisms. The mutual relations among features are also considered by evaluating a score based on the relational spectrum. For recognition of morphologies corresponding to OR nodes, an hypothesis modification strategy is used. Other techniques such as instance, priority update of prototypes, and template matching facility are also used. This algorithm exactly recognized the primary points and supporting points from the multichannel ECG signals.