• Journal of Advanced Marine Engineering and Technology
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• v.38 no.9
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• pp.1112-1118
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• 2014

In this paper, we propose a local descriptor and a similarity measure that is robust to radiometic variations. The proposed local descriptor is made up Haar wavelet filter and it can contain frequency informations about the feature point and its surrounding pixels in fixed region, and it is able to describe feature point clearly under ununiform illumination condition. And a proposed similarity measure is combined with conventional entropy-based similarity and another similarities that is generated by local descriptor. It can reflect similarities between image regions accurately under radiometic illumination variations. We validate with experimental results on some images and we confirm that the proposed algorithm is more superior than conventional algorithms.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.07a
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• pp.201-204
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• 2010

물체 인식 및 추적 기술은 기계가 영상 정보를 기반으로 주변을 인지하고 정황을 파악하는 컴퓨터 비전 분야의 매우 중요한 연구 영역 중 하나이다. 현재까지 이러한 물체 인식/추적에 대한 다양한 연구들이 있어 왔고, 최근 증강현실에 대한 높은 관심을 바탕으로 증강현실을 위한 영상 정보 기반의 정확하고 정교한 추적 기술에 대한 관심 또한 매우 높아졌다. 본 논문에서는 텍스쳐가 없는 단색의 블록에 대해 증강현실을 실현하기 위한 물체 추적 방식을 제안한다. 제안하는 방식은 다수의 블록들을 조합하여 구성하고, 이 조합으로부터 추출한 특징점에 색상 정보 기반의 지역 서술자를 정의함으로써 사전에 정의된 서술자와 의 비교를 통해 물체를 추적하는 방식이다. 제안된 추적 방식은 사전에 기준이 되는 지역 서술자를 정의함에 있어서 기준 영상에 다양한 어파인 변환을 적용함으로써 카메라와 대상물과의 각도가 큰 입력 영상에 대해서도 추적에 실패하지 않는다. 실험을 통해 제안된 방식을 집 모양으로 구성한 블록 조합에 적용하여 3차원 가상 콘텐츠를 증강시켜 봄으로써 제안된 방식의 유용성을 확인하였다. 제안된 방식은 텍스쳐가 없는 환경에서 사용자의 상호작용으로 텍스쳐를 구성하고 이를 추적하는 방식으로 향후 아이들을 위한 교육 프로그램, 모바일 기기에서의 응용 프로그램 등으로 적용 가능하다.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.4
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• pp.116-123
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• 2009

Feature point matching, which is finding the corresponding points from two images with different viewpoint, has been used in various vision-based applications and the demand for the real-time operation of the matching is increasing these days. This paper presents a real-time feature point matching method by using a local descriptor derived by Zernike moments. From an input image, we find a set of feature points by using an existing fast corner detection algorithm and compute a local descriptor derived by Zernike moments at each feature point. The local descriptor based on Zernike moments represents the properties of the image patch around the feature points efficiently and is robust to rotation and illumination changes. In order to speed up the computation of Zernike moments, we compute the Zernike basis functions with fixed size in advance and store them in lookup tables. The initial matching results are acquired by an Approximate Nearest Neighbor (ANN) method and false matchings are eliminated by a RANSAC algorithm. In the experiments we confirmed that the proposed method matches the feature points in images with various transformations in real-time and outperforms existing methods.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.2
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• pp.153-162
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• 2012

In this paper, we propose a new shape similarity measure for M:N polygon pairs regardless of different object cardinalities in the pairs. The proposed method compares the projections of two shape functions onto Zernike polynomial basis functions, where the shape functions were obtained from each overall region of objects, thus not being affected by the cardinalities of object pairs. Moments with low-order basis functions describe global shape properties and those with high-order basis functions describe local shape properties. Therefore several moments up to a certain order where the original shapes were similarly reconstructed can efficiently describe the shape properties thus be used for shape comparison. The proposed method was applied for the building objects in the New address digital map and a car navigation map of Seoul area. Comparing to an overlapping ratio method, the proposed method's similarity is more robust to object cardinality.

• Journal of Broadcast Engineering
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• v.21 no.1
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• pp.51-59
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• 2016

This paper presents a method of DCT-based illuminant compensation to enhance the accuracy of face recognition under an illuminant change. The basis of the proposed method is that the illuminant is generally located in low-frequency components in the DCT domain. Therefore, the effect of the illuminant can be compensated by controlling the low-frequency components. Moreover, a directional high-order local pattern descriptor is used to detect robust features in the case of face motion. Experiments confirm the performance of the proposed algorithm got up to 95% when tested using a real database.

• Proceedings of the Korean Information Science Society Conference
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• 2008.06c
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• pp.36-40
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• 2008

SIMS manages data for various spatial and non-spatial as integral management system to support space information administration environment and support several application works. Without being limited to spatial data that existent spatial Data Mining question language advances handling in this paper, did so that can find useful information from various data connected with automatically data collection, artificial satellite side upside service, remote sensing, GPS. Mobile Computing and data about Spatio-Temporal. Also, we designed spatial Data Mining query language that support a spatial Data Mining exclusive use system based on SIMS.

• KIPS Transactions on Software and Data Engineering
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• v.3 no.9
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• pp.375-380
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• 2014

Under controlled environment, such as fixed viewpoints or consistent illumination, the performance of face recognition is usually high enough to be acceptable nowadays. Face recognition is, however, a still challenging task in real world. SIFT(Scale Invariant Feature Transformation) algorithm is scale and rotation invariant, which is powerful only in the case of small viewpoint changes. However, it often fails when viewpoint of faces changes in wide range. In this paper, we use Affine SIFT (Scale Invariant Feature Transformation; ASIFT) to detect affine invariant local descriptors for face recognition under wide viewpoint changes. The ASIFT is an extension of SIFT algorithm to solve this weakness. In our scheme, ASIFT is applied only to gallery face, while SIFT algorithm is applied to probe face. ASIFT generates a series of different viewpoints using affine transformation. Therefore, the ASIFT allows viewpoint differences between gallery face and probe face. Experiment results showed our framework achieved higher recognition accuracy than the original SIFT algorithm on FERET database.

• 어항어장
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• s.89
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• pp.41-47
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• 2010

전국어업지역에 큰 영향을 미칠 가능성이 있는 리스크로서 지진 해일 재해 리스크의 감재대책에 대한 기본적인 사고에 의거, 위기관리의 관점에서 서술하고자 한다. 전국의 어항 어업 취락에서 지진 해일 재해의 리스크를 증대시키는 요인으로서 협소한 토지에 어항시설이나 가옥의 밀집, 고령화의 진행에 의해 재해시 피보호자가 되기 쉬움, 낚시객 해수욕객 등 지리에 어두운 외래자의 방문 증가, 어선이나 어업 양식시설의 표류 우려 등 어업 지역 특유의 여러가지 리스크 인자를 가지고 있다.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.106-109
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• 2009

Recently, image matching becomes important in Computer Aided Diagnosis (CAD) due to the huge amount of medical images. Specially, texture feature is useful in medical image matching. However, texture features such as co-occurrence matrices can't describe well the spatial distribution of gray levels of the neighborhood pixels. In this paper we propose a frequency domain-based texture feature extractor that describes the local spatial distribution for medical image retrieval. This method is based on 2D Local Discrete Fourier transform of local images. The features are extracted from local Fourier histograms that generated by four Fourier images. Experimental results using 40 classes Brodatz textures and 1 class of Emphysema CT images show that the average accuracy of retrieval is about 93%.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.207-210
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• 2007

최근 전자파에 일반인에 대한 관심이 높아지고 있고, 기업들의 환경경영의 일환으로 전자파환경 관리도 하나의 이슈로 대두되고 있다. 초고속인터넷서비스 속도개선을 위해 통신장치를 기존의 전화국사내에서 가입자 주택 가까이 또는 주택 건물의 내부로 이동하여 설치하고 있다. 이런 경우 주변 거주자들은 전자파의 인체 유해성에 대한 우려를 하게 되며, 이로 인해 일부 장치설치 곤란하여 서비스제공에 어려움이 발생하기도 한다. 본 논문은 초고속서비스 제공을 위해 가입자 가까이에 설치된 여러 지역의 옥외 통신설비 주변에서 전자파 측정기술을 서술하고 측정된 결과를 국내 기준과 비교 분석하였다. 측정결과 국내 기준보다 매우 낮은 결과를 보였다.