• Title/Summary/Keyword: Perspective Transform

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Interactive Augmented Reality Using Live Markers (라이브 마커를 이용한 대화형 증강 현실)

  • Jang, Moon-Seok;Park, Han-Hoon;Park, Jong-Il
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2005.11a
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    • pp.57-60
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    • 2005
  • 본 논문에서는 대화형 증강 현실을 위한 간단하고 유용한 방법을 제안한다. 대화형 증강 현실을 구현하기 위한 가장 일반적인 방법은 ARToolkit 라이브러리를 사용하는 것이다. 본 논문에서는 ARToolkit 라이브러리의 기능을 그대로 사용하지만 ARToolkit 라이브러리에서 사용하는 그래픽 마커를 라이브 마커로 대체한다. 따라서, 그래픽 마커를 사용할 때보다 직관적이면서도 편리한 사용자 인터페이스를 제공해 줄 수 있다. 단, 라이브 마커를 사용하기 때문에 ARToolkit 라이브러리의 마커인식(Identification)을 위한 패턴 매칭 기술은 사용될 수 없으므로, 보다 정교한 객체 인식(object recognition) 기술이 요구된다. 본 논문에서는 원근 변환(perspective transformation)에 불변한 특성을 가지는 ART 기술자(Angular Radial Transform descriptor)를 사용한다. ART 기술자에 대한 간단한 성능 검증을 통해 라이브 마커에 적용 가능성을 확인하였고, 다양한 실험을 통해 라이브 마커의 효용성을 확인하였다. 본 논문에서 제안한 라이브 마커는 기존의 ARToolkit 사용자들에게 발전된 인터페이스 개념을 제공함으로써, 다양한 증강 현실의 구현에 응용될 수 있으리라 기대된다.

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Efficient Lane Detection Method using Improved Bird's Eye View Transform (개선된 버드아이뷰 변환을 활용한 효율적인 차선 검출 방법)

  • Jeong, Hyeon-Seok;Im, Seok-Ho;Yoon, Hyeon-Ju
    • Proceedings of the Korea Information Processing Society Conference
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    • 2017.11a
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    • pp.901-904
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    • 2017
  • 차선 검출은 자율주행 자동차의 가장 기본 기능 중의 하나이다. 전방 카메라를 통하여 얻은 입력 영상을 변환하여 주행 방향을 정할 수 있도록 차로를 검출하는 방법은 여러 가지가 있는데, 본 논문에서는 버드아이뷰 영상을 활용하는 방법을 채택하고 여러 가지 성능이 제한적인 임베디드 시스템에서 이를 보다 효율적으로 수행할 수 있도록 EPM(Expected Perspective Mapping) 방법과 변환 영상을 이용해 차로를 검출하는 슬라이딩 윈도우 알고리즘의 개선 방안을 제안한다. 제안된 방법은 기존의 차선 검출 방법에 비해 약 30% 이상 적은 연산량으로 수행할 수 있으면서 기존 방법과 동일한 결과를 생성하여 실시간성이 중요한 상황에서 정확한 차선 검출을 할 수 있음을 보여 준다.

Real-time Lane Detection Method using Inverse Perspective Transform and Lane Filter (역 투시변환과 차선 필터를 이용한 실시간 차선 검출방법)

  • Heo, Hwan;Kim, Sung-Hun;Chae, Il-Moon;Han, Ki-Tea
    • Proceedings of the Korea Information Processing Society Conference
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    • 2012.11a
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    • pp.545-548
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    • 2012
  • 본 논문에서는 영상내 관심영역의 역 투시변환과 차선검출필터를 적용한 실시간 차선검출방법을 제안한다. 영상의 시작 프레임에서 소실점을 찾고 이를 기준으로 관심영역을 설정하고 차선을 예측하였으며, 예측된 차선을 기반으로 역 투시변환계수를 추출하여 원근감이 제거된 영상을 얻고, 이로부터 차선을 검출하였다. 제안한 방법은 원근감이 제거된 영상에 차선검출 필터를 적용하여 차선을 검출하는 방법으로, 처리영역을 축소하고 처리과정을 단순화 함으로써 초당 50 frames 정도의 양호한 차선검출 결과를 보였다.

3D Object Recognition Using Appearance Model of Feature Point (특징점 Appearance Model을 이용한 3차원 물체 인식)

  • Joo, Seong-Moon;Park, Jae-Wan;Lee, Chil-Woo
    • Proceedings of the Korea Information Processing Society Conference
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    • 2013.11a
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    • pp.1536-1539
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    • 2013
  • 3차원 물체는 카메라의 시선 방향에 따라 다른 영상을 생성하므로 2차원 영상만으로 3차원 물체를 인식하는 것은 쉬운 일이 아니다. 특히 영상생성 시 강한 perspective transformation 이 발생할 경우 2차원 국소 특징을 이용하는 SIFT(Scale-Invariant Feature Transform) 알고리즘은 매칭에 활용하기 어렵다. 본 논문에서는 3차원 물체를 하나의 특정 축 중심으로 회전시키면서 얻은 복수의 영상을 학습 데이터로 활용하여 SIFT 알고리즘을 개선한 물체인식 방법을 제안한다. 이 방법은 복수 영상의 특징점들을 하나의 특징 공간으로 합성하고 그 특징점들 간의 기하학적인 제약조건을 확인하여 3차원 물체를 인식하는 방법이다. 실험에서는 알고리즘의 유용성을 먼저 확인하기 위해 조명조건과 카메라의 위치를 일정하게 유지하였다. 이 방법에 의해 SIFT 알고리즘만으로 인식이 힘들었던 3차원 물체의 다양한 외관(appearance) 인식이 가능하게 되었다.

Electoralism, Ritual Process, and Voter Rationalities in Southeast Asia

  • Aguilar, Filomeno V.Jr.
    • SUVANNABHUMI
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    • v.10 no.1
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    • pp.149-174
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    • 2018
  • Southeast Asians participate in elections eagerly, a fact indexed by the high electoral participation rates across a range of political conditions in the region. What gives elections in Southeast Asia such high legitimacy? Using data from Indonesia and the Philippines, this article emphasizes the need to understand peoples' rationalities, which are informed by meanings generated by prevailing cultural practices. From this perspective, electoralism can be understood as a cultural phenomenon that conforms to the structure of a ritual. Despite the democratic deficit in many electoral exercises, elections share the attractiveness and fun of traditional community festivities. Voters participate in elections as a testament to membership in a community. Although they do not always transform the existing social arrangements, elections embed contradictory impulses in the same way that cockfights do. A procedure of formal democracy authored elsewhere, electoralism has been localized in Southeast Asia and invested with indigenous significance.

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Estimation of Displacements and Velocities of Objects from Soccer Image Sequences (축구 영상 시퀀스로부터 물체 이동거리와 속도 측정)

  • Nam, Si-Wook;Yi, Jong-Hyon;Lee, Jae-Cheol;Park, Yeung-Gyu;Kim, Jai-Hie
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.38 no.2
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    • pp.1-8
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    • 2001
  • In this paper, we propose an algorithm which estimates the displacements and velocities of objects in the soccer field from the soccer image sequences. Assuming the time interval of an object movement is given, we transform the object positions into those in the soccer field model and compute the distance and the velocity. When four corresponding pairs of the feature points, such as the crossing points of the lines in the soccer field, exist and three of them are not on a line, we transform the object positions in the soccer image into those in the soccer field by using the perspective displacement field model. In addition, when the soccer image has less than four feature points, we first transform the object positions into those in the image which has more than four feature points, and then transform the positions into those in the soccer field again. To find the coordinate transformation between two images, we estimate the panning and zooming for consecutive images in the sequence. In the experimental results, we quantitatively evaluated the estimation accuracy by applying our algorithm to the synthetic. soccer image sequences generated by graphic tools, and applied it to the real soccer image sequences for broadcasting to show its usefulness.

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Analysis of Formal Aesthetics of Fashion Designer's Works -Focused on Madeleine Vionnet & Christian Dior- (패션디자인 작품에 나타난 형태미 분석 -비요네와 디올의 작품을 중심으로-)

  • Yun, Ji-Young
    • Journal of the Korean Society of Clothing and Textiles
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    • v.29 no.12 s.148
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    • pp.1582-1594
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    • 2005
  • The purpose of this study is to rediscover the value of form in fashion design by developing a new perspective of design appreciation. By examining and modifying the theories of Wolfflin and Belong, this paper tries to of for a new perspective for analyzing the characteristics of form in fashion designers' works. The three new perspective, Flat & Rounded, Closed & Opened and Part & Whole, can be used to analyze the formative aesthetic character of Vionnet's and Dior's works. Ten of Vionnet's and eleven of Dior's representative works selected and applied Delong's visual priority diagram to analyze their character. Vionnet and Dior, emphasized form and construction in their design and applied geometric shapes in their works. The main differences between Vionnet and Dior is that Vionnet's work transforms from geometric shapes in 2-dimentional space to drapery shapes in 3-dimensional space, Dior's work displays geometric shapes in 3-dimensional space. Vionnet created new formative art through the relationship between the clothes and human body. Vionnet's work has distinctively different qualities depending on whether the space is 2-dimensional or 3-dimensional showing transposition of form. In 2-dimensional space, Vionnet's works consist of triangles, rectangles and circles which are 'flat' and 'closed' in quality. These transform to solid forms by draping bias fabrics, which have a 'rounded' and 'open' quality. Dior tended to show artificial form rather than the natural lines of the body which is very different with Vionnet. Dior created clothes by using solid geometric form such as spheres, prisms, cylinders, pyramids and cubes in 3-dimensional space, which were visualized through constructive technique such as dart manipulation, boning, gathering, tucking, pleating, shirring and layering. Dior's works have their own form which does not relate with body shape. So his Works have a 'rounded' and 'closed' quality.

The Evolution of Electromechanical Admittance from Mode-converted Lamb Waves Reverberating on a Notched Beam (노치가 있는 보에서 잔향하는 모드변환 램파의 전기역학적 어드미턴스 전이)

  • Kim, Eun Jin;Park, Hyun Woo
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.26 no.3
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    • pp.270-280
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    • 2016
  • This paper investigates the evolution of EM admittance of piezoelectric transducers mounted on a notched beam from wave propagation perspective. A finite element analysis is adopted to obtain numerical solutions for Lamb waves reverberating on the notched beam. The mode-converted Lamb wave signals due to a notch are extracted by using the polarization characteristics of piezoelectric transducers collocated on the beam. Then, a series of temporal spectrums are computed to demonstrate the evolution of EM admittance through fast Fourier transform of the mode-converted Lamb wave signals which are consecutively truncated in the time domain. When truncation time is relatively small, the corresponding temporal spectrum is governed by the characteristics of the input driving frequency. As truncation time becomes large, however, the modal characteristics of the notched beam play a crucial role in the temporal spectrum within the input driving frequency band. This implies that mode-converted Lamb waves reverberating on the beam contributes to the resonance of the beam. The root mean square values are computed for the temporal spectrums in the vicinity of each resonance frequency. The root mean square values increase monotonically with respect to truncation time for any resonance frequencies. Finally the implications of the numerical observation are discussed in the context of damage detection of a beam.

Efficient Image Warping Mechanism Using Template Matching and Partial Warping (템플릿 매칭과 부분 워핑을 이용한 효율적인 원근 영상 워핑 기법)

  • Jeong, Dae-Heon;Cho, Tai-Hoon
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2017.05a
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    • pp.339-342
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    • 2017
  • Geometric transform of an image is used to image correction. Ridid-Body, Simlilary transform, etc, many correction methods are exist in computer vision. Image warping is used to correction for image with perspective. To image warping I extracted 4 feature point about warping position. But It is difficult to extract 4 points accurately and warping result with these point is occurs error over 3 or 4 pixel at warping position. So I used template matching to extract 4 points correctly and selected repeatedly 2 points of 4 points because to confirm result correctly. positions of 2 points are changed in near of 3 by 3 pixel and warped each change. So I selected optimal 4 points with a error of less than 1 pixel and finally, warped image using optimal points. For this way is possible to obtain optimum result.

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Facial Features and Motion Recovery using multi-modal information and Paraperspective Camera Model (다양한 형식의 얼굴정보와 준원근 카메라 모델해석을 이용한 얼굴 특징점 및 움직임 복원)

  • Kim, Sang-Hoon
    • The KIPS Transactions:PartB
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    • v.9B no.5
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    • pp.563-570
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    • 2002
  • Robust extraction of 3D facial features and global motion information from 2D image sequence for the MPEG-4 SNHC face model encoding is described. The facial regions are detected from image sequence using multi-modal fusion technique that combines range, color and motion information. 23 facial features among the MPEG-4 FDP (Face Definition Parameters) are extracted automatically inside the facial region using color transform (GSCD, BWCD) and morphological processing. The extracted facial features are used to recover the 3D shape and global motion of the object using paraperspective camera model and SVD (Singular Value Decomposition) factorization method. A 3D synthetic object is designed and tested to show the performance of proposed algorithm. The recovered 3D motion information is transformed into global motion parameters of FAP (Face Animation Parameters) of the MPEG-4 to synchronize a generic face model with a real face.