• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.715-718
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• 2001

인터넷 문화 활성화에 따라, 새로이 제작된 멀티 미디어 컨텐츠의 부가가치가 높아지고 있으며, 저작물에 대한 도용 또한 문제시 되고 있다. 멀티미디어 매체 중에서 이미지는 큰 비중을 차지하고 있으며, 인터넷 상에서 도용된 이미지는 원본으로 부터 크기 확대 및 축소, 가로/세로비 변화, 문자 강제 색인 등의 형태로 변형되어 나타난다. 본 논문은 이와 같이 웹상에서 변형 도용된 이미지를 검색하기 위하여, MPEG-7 컬러 기술자인 Color Layout 기술자를 이용하여 모든 변형된 이미지를 검색하는 방법을 제안한다. 제안된 방법은 단순 변형 및 2 가지 이상이 혼합된 복합 변형된 도용 이미지들에 대해서도 검색이 가능하다. 정량적 평가를 위해 인위적으로 조작된 351 개의 이미지를 대상으로 MPEG-7 검색 성능 평가 지수인 ANM-RR (Average Normalized Modified Retrieval Rank)를 이용하여 효용성을 보였다.

• Journal of the Korean Geotechnical Society
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• v.25 no.12
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• pp.119-130
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• 2009

To measure the soil deformation, two common techniques of the digital image analysis-Particle Image Velocimetry (PIV) and Digital Image Correlation (DIC)-have been used. To generally apply these techniques to the soils, the accuracy of these techniques should be evaluated under various conditions. In this study, the influence factors including the image resolution, the degree of displacement and deformation, the size of pixel subsets, and analysis techniques were analyzed. The deformation of an idealized particle assembly using the discrete element method was measured by the digital image analyses, and then the results were compared with the actual deformations. To conduct the optimal digital image analysis, various factors are systematically analyzed in terms of the degree of the displacement and the deformation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.5
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• pp.527-534
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• 2014

Poroelastic analyses of fiber-reinforced composites were performed using image-based computational models. The section image of a porous matrix was analyzed in order to investigate the porosity, number of pores, and distribution of pores. The resolution, location, and size of the section image were considered to quantify the effective elastic modulus, poroelastic parameter, and strain energy density using the image-based computational models. The poroelastic parameter was calculated from the effective elastic modulus and pore pressure-induced strain. In addition, the results of the poroelastic analyses were verified through representative volume elements by simplifying various pore configurations and arrangements.

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.393-396
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• 2000

본 논문에서는 영상의 화소값으로부터 추출된 유사 특징점(quasi-feature point)을 이용한 이미지 모자이킹 알고리즘을 제안한다. 유사 특징점의 선택은 전역 정합(global matching)의 결과로부터 중첩된 영역을 4개의 부영역(sub-area)으로 분할하고, 각각의 분할된 부 영역에서 국부 분산(local variance)의 크기가 큰 블록을 선정, 이 블록의 중심 화소를 유사 특징점으로 선택한다. 유사 특징점에 대한 정합은 카메라 이동에 따른 왜곡(distortion)과 조명의 변화를 고려한 블록 정합 알고리즘(block matching algorithm)을 이용한다.

• Journal of the Korean Geotechnical Society
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• v.27 no.7
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• pp.5-16
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• 2011

Digital image analysis techniques have been developed and utilized in the field of solid mechanics and fluid mechanics to measure the deformation and velocity of a target object. The deformation measurement systems based on Particle Image Velocimetry (PIV) and Digital Image Correlation (DIC) have been attempted in geotechnical testings (e.g., physical model tests) for observing the deformation of soils. The digital image analysis is influenced by image pattern of test materials, resolution of the used digital camera, target area, image analysis techniques, and analysis conditions. Therefore, optimal analysis conditions should be determined to obtain high quality results on soil deformations. In the present study, various influence factors on the digital image analysis were described and summarized. The optimizing procedure for high accurate results was then proposed. Finally, the applicability of the developed procedure was examined.

• Journal of Korea Multimedia Society
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• v.15 no.2
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• pp.179-194
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• 2012

Digital image forgery is becoming a topic of great interest with regard to honesty in imaging. We can often see forged digital images in a variety of places, such as the internet, and magazines, and in images used in political ads, etc. These can reduce the reliability and factual basis of the information contained in image. Therefore, objectivity is needed to determine if the image is forged so as to prevent confusion in the viewing public. Most digital forgeries consist of image resizing, rotating including the following interpolations. To find evidence of interpolation in forged images, this paper proposes a new method for detecting digital image forgery using general interpolation factors analyzed through re-interpolation algorithm of the forged images in order to determine the differences in the patterns. Through the re-interpolation algorithm we could detect the forged region and filtering region used image retouching included to interpolation.

• Journal of Korea Society of Industrial Information Systems
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• v.6 no.2
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• pp.16-22
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• 2001

In this paper we mose a new scheme for recognition of deformed letters by extracting feature vectors based on Gibbs distributions which are well suited for representing the spatial continuity. The extracted feature vectors are comprised of 2-D conditional moments which are invariant under translation, rotation, and scale of an image. The Algorithm for pattern recognition of deformed letters contains two parts: the extraction of feature vector and the recognition process. (i) We extract feature vector which consists of an improved 2-D conditional moments on the basis of estimated conditional Gibbs distribution for an image. (ii) In the recognition phase, the minimization of the discrimination cost function for a deformed letters determines the corresponding template pattern. In order to evaluate the performance of the proposed scheme, recognition experiments with a generated document was conducted. on Workstation. Experiment results reveal that the proposed scheme has high recognition rate over 96%.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.11a
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• pp.241-244
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• 2004

일반적으로 메쉬(mesh)는 비정규 연결 형태(irregular connectivity)로 되어 있다. 리메싱(remeshing)은 비정규 연결 형태의 메쉬를 정규 연결 형태(regular connectivity)로 바꾸어 주는 작업이다. 메쉬의 기하 정보가 2D 그리드에 저장이 되어 있는 기하이미지(geometry Images)는 비정규 연결 형태의 메쉬를 완전 정규 형태(completely regular connectivity)로 리메싱하는 데 사용된다. 원본 메쉬를 기하 이미지로 생성하는 방법은 변형되는 크기를 최소화 하는 스트레치 메트릭(stretch metric)을 기반으로 이루어 졌다. 이 방법은 리메싱된 메쉬의 언더샘플링(undersampling)을 줄여 주게 된다. 하지만 리메싱 과정에서 생기는 오버샘플링(oversampling)은 줄여 주지 못한다. 본 논문에서는 정점(vertex)의 법선 벡터(normal vector)를 이용하여 기하이미지의 오버샘플링을 줄이는 방법을 제시한다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2018.11a
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• pp.122-123
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• 2018

본 논문에서는 옥타브(sacle vector, octave)를 0, 시그마(sigma)는 1.6, 간격(intervals)은 3으로 설정하여 검출한 RobHess SIFT 특징들로 데이터 셋을 만들어 딥 러닝 모델인 VGG-16을 기반으로 SIFT 이미지 특징을 검출하는 방법을 제안한다. DIV2K 데이터 셋을 $33{\times}33$ 크기로 잘라서 데이터 셋을 구성하였고, 흑백 영상으로 판별하는 SIFT와는 달리 RGB 영상을 사용 하였다. 영상을 좌 우 반전, 밝기, 회전, 크기를 조절하여 원본 영상을 변형시켜 네트워크 학습 및 평가를 진행하였다. 네트워크는 영상의 가운데에 위치한 픽셀이 특징점인지 아닌지를 판별한다. 검증 데이터의 결과 98.207%의 정확도를 얻었다.

• Journal of Korea Multimedia Society
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• v.2 no.2
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• pp.129-136
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• 1999

A linear feature often provide sufficient information for image understanding and coding. An objective of the research reported in this paper is to develop and analyze the reliable methods of extracting lines in gray scale images. The Hough Transform is known as one of the optimal paradigms to detect or identify the linear features by transforming edges in images into peaks in parameter space. The scheme proposed here uses the fuzzy gradient direction model and weights the gradient magnitudes for deciding the voting values to be accumulated in parameter space. This leads to significant computational savings by restricting the transform to within some support region of the observed gradient direction which can be considered as a fuzzy variable and produces robust results.