• 대한원격탐사학회지
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• 제26권6호
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• pp.731-740
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• 2010

A region merging technique is suggested in this paper for the segmentation of high-spatial resolution imagery. It employs a region growing scheme based on the region adjacency graph (RAG). The proposed algorithm uses directional neighbor-line average feature vectors to improve the quality of segmentation. The feature vector consists of 9 components which includes an observation and 8 directional averages. Each directional average is the average of the pixel values along the neighbor line for a given neighbor line length at each direction. The merging coefficients of the segmentation process use a part of the feature components according to a given merging coefficient order. This study performed the extensive experiments using simulation data and a real high-spatial resolution data of IKONOS. The experimental results show that the new approach proposed in this study is quite effective to provide segments of high quality for the object-based analysis of high-spatial resolution images.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.1078-1083
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• 1992

Extracting the process planning information from the CAD data is the key issue in integrated CAD/CAM system. In this paper, we develop algorithms for extracting the shape and setup configuration for NC machining of prismatic parts. In determining the workpart shape, the minimum-enclosing condept is applied so that the material waste is minimized. To minimize the number of setups, feature based algorithm is developed considrint the part shape, tool shape, and tool approach direction. The validity and effectiveness of the developed algorithms were tested by computer simulations.

• 산업기술연구
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• 제20권B호
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• pp.207-211
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• 2000

For efficient massive image retrieval, an image retrieval requires that several important objectives are satisfied, namely: automated extraction of features, efficient indexing and effective retrieval. In this work, we present a technique for extracting the 4-dimension directional feature. By directional detail, we imply strong directional activity in the horizontal, vertical and diagonal direction present in region of the image texture. This directional information also present smoothness of region. The 4-dimension feature is only indexed in the 4-D space so that complex high-dimensional indexing can be avoided.

• Journal of Information Technology Applications and Management
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• 제10권4호
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• pp.135-147
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• 2003

With the development of multimedia and optical technologies, application systems with facial features hare been increased the interests of researchers, recently. The previous research efforts in face processing mainly use the frontal images in order to recognize human face visually and to extract the facial expression. However, applications, such as image database systems which support queries based on the facial direction and image arrangement systems which place facial images automatically on digital albums, deal with the directional characteristics of a face. In this paper, we propose a method to detect facial directions by using facial features. In the proposed method, the facial trapezoid is defined by detecting points for eyes and a lower lip. Then, the facial direction formula, which calculates the right and left facial direction, is defined by the statistical data about the ratio of the right and left area in facial trapezoids. The proposed method can give an accurate estimate of horizontal rotation of a face within an error tolerance of $\pm1.31$ degree and takes an average execution time of 3.16 sec.

• 한국컴퓨터정보학회논문지
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• 제22권11호
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• pp.111-116
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• 2017

This paper proposes a data mining approach to predicting stock price direction. Stock market fluctuates due to many factors. Therefore, predicting stock price direction has become an important issue in the field of stock market analysis. However, in literature, there are few studies applying data mining approaches to predicting the stock price direction. To contribute to literature, this paper proposes comparing single classifiers and ensemble classifiers. Single classifiers include logistic regression, decision tree, neural network, and support vector machine. Ensemble classifiers we consider are adaboost, random forest, bagging, stacking, and vote. For the sake of experiments, we garnered dataset from Korea Stock Exchange (KRX) ranging from 2008 to 2015. Data mining experiments using WEKA revealed that random forest, one of ensemble classifiers, shows best results in terms of metrics such as AUC (area under the ROC curve) and accuracy.

• 디지털콘텐츠학회 논문지
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• 제2권2호
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• pp.179-189
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• 2001

본 논문에서는 지문의 방향분포를 기반으로 하여 전처리과정을 최소화하고 특징벡터의 크기를 축소하여 개인의 인증 및 인식 시스템에서의 시스템 처리속도와 검색속도 향상을 주된 연구목적으로 하였다. 지문의 방향분포는 지문의 융선과 골이 이루는 부분적인 방향성분의 집합으로서 가버필터 뱅크를 통해 8-방향 성분들로 추출된다. 이렇게 생성된 방향분포는 불연속적인 특성을 갖게 되는데 이를 연속적인 방향성분으로 근사화하여 방향영상으로 시각화한다. 이 후 지문의 중심 이 되는 기준점을 설정하고 기준점으로부터 32-방향, 6-단계 거리에 미리 정해진 192개 지점에서의 방향성분값들을 추출하여 특징벡터를 생성한다. 그 결과 기존의 다른 알고리즘보다 작은 크기의 특징벡터를 사용함으로써 전체 처리속도는 훨씬 증가하면서도 같은 수준의 인식률을 얻을 수 있었다.

• 제어로봇시스템학회논문지
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• 제22권9호
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• pp.738-744
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• 2016

In this paper, a robust visual odometry system has been proposed and implemented in an environment with dynamic illumination. Visual odometry is based on stereo images to estimate the distance to an object. It is very difficult to realize a highly accurate and stable estimation because image quality is highly dependent on the illumination, which is a major disadvantage of visual odometry. Therefore, in order to solve the problem of low performance during the feature detection phase that is caused by illumination variations, it is suggested to determine an optimal threshold value in the image binarization and to use an adaptive threshold value for feature detection. A feature point direction and a magnitude of the motion vector that is not uniform are utilized as the features. The performance of feature detection has been improved by the RANSAC algorithm. As a result, the position of a mobile robot has been estimated using the feature points. The experimental results demonstrated that the proposed approach has superior performance against illumination variations.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제3권11호
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• pp.495-502
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• 2014

비접촉 장문을 인식하기 위해서는 영상의 크기 및 회전 변형을 효과적으로 해결해야 한다. 본 연구에서는 손의 크기와 방향에 따라 관심영역(ROI)을 추출한 후 정규화하여 일차적으로 이러한 변형을 최소화하였다. 본 논문에서는 KLT(Kanade-Lukas-Tomasi) 특징점에 기반한 비접촉 장문인식 방법을 제안한다. 대응되는 KLT 특징점 주위의 국소영역에 대한 텍스처를 비교하여 대응되는 특징점을 검출한 후, 특징점 쌍의 변위 크기와 방향을 나타내는 변위벡터들 간의 유사도를 비교하여 장문을 인식한다. CASIA 공개 데이터베이스를 이용한 실험결과 제안된 방법이 비접촉 장문인식에 효과적임을 확인할 수 있었다. 특히 다중 가버 필터를 이용하였을 때 99%를 상회하는 정인식률을 얻을 수 있었다.

• 한국컴퓨터정보학회논문지
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• 제16권8호
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• pp.95-101
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• 2011

본 논문에서는 픽셀 연결성 추적을 이용한 의사 특징점 제거에 관하여 연구하였다. 특징점을 추출하는 방법에는 교차수를 이용한 방법이 있다. 그러나 교차수를 이용한 방법에서는 의사 특징점이 많이 추출된다. 교차수를 이용한 방법에서 잘못 추출된 특징점들을 제거하기 위하여 단점과 분기점 주위에 있는 8개 픽셀을 추적하여 조건을 만족하는 경우 실제 특징점으로 추출하고 조건을 만족하지 않는 경우 의사 특징점이므로 제거하였다. 성능 평가를 위하여 교차수를 이용한 방법과 픽셀 연결성 추적을 이용하여 추출된 실제 특징점을 비교하였으며, 실험결과 픽셀 연결성 추적을 이용하여 궁상문형, 와상문형, 제상문형에 대하여 의사특징점이 각각 47%, 40%, 30% 제거되었음을 알 수 있었다.

• 대한의용생체공학회:의공학회지
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• 제8권1호
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• pp.75-80
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• 1987

With the conventional CW Doppler velocity meter, bl-directional velocities cannot be separated. The new CW Doppler system uses quadrature detection and phase rotation to produce simultaneous independent audio and velocity signals for forward and reverse blood flow direction, is fabricated. Specially, this system shows that phase rotation method for flow direction separation provides easy and satisfactory feature. From in vivo blood flow measurement, we can easily differentiate typical artery flow from vein flow, and measure both velocity characteristics qualitatively.