• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2016.11a
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• pp.144-145
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• 2016

디지털 컨텐츠는 UHD, 3D, 파노라마 영상 등 다양한 형태로 발전되고 있다. 그 중 파노라마 영상은 여러 영상을 정합하여 넓은 시야각을 제공하는 컨텐츠로 전문적인 기술자들을 중심으로 제작되고 있다. 또한 디지털 컨텐츠의 제작자는 전문가에서 일반인으로까지 범위가 확장되었고, 발전된 형태의 컨텐츠를 일반인이 스마트폰 등의 개인 단말로 손쉽게 제작할 수 있도록 해주는 컨텐츠 생성 기술이 발달되고 있다. 이에 본 논문에서는 일반 사용자들이 각각의 스마트폰 단말로 촬영한 여러 동영상들을 하나의 파노라마 영상으로 제작하기위한 기술 중, 각기 다른 스마트폰의 시간축을 이미지 매칭을 통해 하나의 통일된 시간축으로 동기화 시키는 기법에 관하여 연구하였다. 이를 위해, 본 논문에서는 동영상에서 시간정보로 이용하기 위한 오브젝트의 움직임이 포함된 시퀀스를 찾는 방법과 해당 시퀀스를 이용하여 다른 동영상과의 이미지 매칭으로 시간축을 동기화 시키는 방법을 제안한다.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06c
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• pp.49-52
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• 2010

본 논문에서는 윤곽선 이미지 매칭에서 회전-불변 거리를 계산하는 효율적 방법을 제안한다. 회전-불변 거리 계산은 이미지 시계열을 한 칸씩 회전하면서 매번 유클리디안 거리를 계산해야 하는 고비용의 연산이다. 본 논문에서는 엔빌로프 기반 하한을 사용하여 불필요한 회전-불변 거리 계산을 크게 줄이는 효율적인 해결책을 제시하다. 이를 위해, 먼저 질의 시퀀스 대상의 엔빌로프 작성과 이의 하한 개념을 제시한다.다음으로, 엔빌로프 기반 하한을 회전-불변 거리 계산에 사용하면 많은 수의 회전-불변 거리계산을 줄일 수 있음을 보인다. 실험 결과, 제안한 엔빌로프 기반 매칭 기법은 기존 기법에 비해 최대 수배에서 수십배까지 매칭 성능을 향상시킨 것으로 나타났다.

• The KIPS Transactions:PartD
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• v.18D no.1
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• pp.9-22
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• 2011

In this paper we present an efficient solution to rotation?invariant boundary image matching. Computing the rotation-invariant distance between image time-series is a time-consuming process since it requires a lot of Euclidean distance computations for all possible rotations. In this paper we propose a novel solution that significantly reduces the number of distance computations using the envelope-based lower bound. To this end, we first present how to construct a single envelope from a query sequence and how to obtain a lower bound of the rotation-invariant distance using the envelope. We then show that the single envelope-based lower bound can reduce a number of distance computations. This approach, however, may cause bad performance since it may incur a larger lower bound by considering all possible rotated sequences in a single envelope. To solve this problem, we present a concept of rotation interval, and using the rotation interval we generalize the envelope-based lower bound by exploiting multiple envelopes rather than a single envelope. We also propose equi-width and envelope minimization divisions as the method of determining rotation intervals in the multiple envelope approach. Experimental results show that our envelope-based solutions outperform existing solutions by one or two orders of magnitude.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04b
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• pp.604-606
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• 2001

최근 들어 이미지 모자익은 가상현실과 웹 브라우저 상에서의 가상환경 구축, 관광, 광고 등, 많은 응용분야에서 관심을 모으고 있다. 이미지 모자익을 위해 해결해야 할 주된 문제는 이미지들 간의 중복되는 영역에서 정확한 대응점을 찾는 것이다. 지금까지 이 대응점을 찾기 위한 노력은 시스템의 많은 계산량과 시간을 투자해야만 했다. 또한 대부분의 모자익이 여러 차례의 촬영에 의한 정지 화상들 간의 모자익에 그치고 있다. 따라서 본 논문에서는 비디오 카메라를 이용하여 프레임들 간의 중복되는 영역에서 일정한 비교 영역을 지정하고 그 비교 영역 안에서 대응점을 찾는 블럭 매칭 방법을 적용함으로써 전체적인 모자익 시간을 줄이는 방법을 구현하였다.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.10
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• pp.949-954
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• 2010

Computing the rotation-invariant distance between image time-series is a time-consuming process that incurs a lot of Euclidean distances for all possible rotations. In this paper we propose an innovative solution that significantly reduces the number of Euclidean distances using the triangular inequality. To this end, we first present the notion of self rotation distance and show that, by using the self rotation distance with the triangular inequality, we can prune many unnecessary distance computations. We next present that only one self-rotation is enough for all self-rotation distances required. Experimental results show that our self rotation distance-based methods outperform the existing methods by up to an order of magnitude.

• Journal of Korea Spatial Information System Society
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• v.10 no.2
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• pp.49-62
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• 2008

This paper proposes an indoor location positioning system for the image recognition based LBS. The proposed system is a vision-based location positioning system that is implemented the augmented reality by overlaying the location results with the view of the user. For implementing, the proposed system uses the pattern matching and location model to recognize user location from images taken by a wearable mobile PC with camera. In the proposed system, the system uses the pattern matching and location model for recognizing a personal location in image sequences. The system is estimated user location by the image sequence matching and marker detection methods, and is recognized user location by using the pre-defined location model. To detect marker in image sequences, the proposed system apply to the adaptive thresholding method, and by using the location model to recognize a location, the system can be obtained more accurate and efficient results. Experimental results show that the proposed system has both quality and performance to be used as an indoor location-based services(LBS) for visitors in various environments.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.8
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• pp.1792-1801
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• 2003

In these days, image mosaic is getting interest in the field of advertisement, tourism, game, medical imaging, and so on with the development of internet technology and the performance of personal computers. The main problem of mage mosaic is searching corresponding points correctly in the overlapped area between images. However, previous methods requires a lot of CPU times and data processing for finding corresponding points. And they need repeated recording with a revolution of 360 degree around objects or background. This paper presents a new image mosaic method which generates a panorama image from a video sequence recorded by a general video camera. Our method finds the corresponding points between two successive images by using a new direction oriented 3­step block matching methods. Experimental results show that the suggested method is more efficient than the methods based on existing block matching algorithm, such as full search and K­step search algorithm.

• Journal of Information Technology and Architecture
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• v.10 no.1
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• pp.79-91
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• 2013

This paper proposes a systematic methodology that could be used to decide which one shows the best performance among space filling curves (SFCs) in applying lower-dimensional transformations to histogram sequences. A histogram sequence represents a time-series converted from an image by the given SFC. Due to the high-dimensionality nature, histogram sequences are very difficult to be stored and searched in their original form. To solve this problem, we generally use lower-dimensional transformations, which produce lower bounds among high dimensional sequences, but the tightness of those lower-bounds is highly affected by the types of SFC. In this paper, we attack a challenging problem of evaluating which SFC shows the better performance when we apply the lower-dimensional transformation to histogram sequences. For this, we first present a concept of spatial locality, which comes from an intuition of "if the entries are adjacent in a histogram sequence, their corresponding cells should also be adjacent in its original image." We also propose spatial locality preservation metric (slpm in short) that quantitatively evaluates spatial locality and present its formal computation method. We then evaluate five SFCs from the perspective of slpm and verify that this evaluation result concurs with the performance evaluation of lower-dimensional transformations in real image matching. Finally, we perform k-NN (k-nearest neighbors) search based on lower-dimensional transformations and validate accuracy of the proposed slpm by providing that the Hilbert-order with the highest slpm also shows the best performance in k-NN search.

• The Journal of the Korea Contents Association
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• v.6 no.12
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• pp.269-277
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• 2006

In this paper, we propose an interactive system that generates emotional expressions from arm gestures. By extracting relevant features from key frames, we can infer emotions from arm gestures. The necessary factor for real-time animation is tremendous frame rates. Thus, we propose processing facial emotion expression with 3D application for minimizing animation time. And we propose a method for matching frames and actions. By matching image sequences of exagerrated arm gestures from participants, they feel that they are communicating directly with the portraits.

• The Journal of the Korea Contents Association
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• v.8 no.1
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• pp.212-227
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• 2008

Since 3D face can be rotated freely in 3D space and illumination effects can be modeled properly, 3D face modeling Is more precise and realistic in face pose, illumination, and expression than 2D face modeling. Thus, 3D modeling is necessitated much in face recognition, game, avatar, and etc. In this paper, we propose a 3D face modeling method based on 3D morphable shape modeling. The proposed 3D modeling method first constructs a 3D morphable shape model out of 3D face scan data obtained using a 3D scanner Next, the proposed method extracts and matches feature points of the face from 2D image sequence containing a face to be modeled, and then estimates 3D vertex coordinates of the feature points using a factorization based SfM technique. Then, the proposed method obtains a 3D shape model of the face to be modeled by fitting the 3D vertices to the constructed 3D morphable shape model. Also, the proposed method makes a cylindrical texture map using 2D face image sequence. Finally, the proposed method builds a 3D face model by rendering the 3D face shape model with the cylindrical texture map. Through building processes of 3D face model by the proposed method, it is shown that the proposed method is relatively easy, fast and precise than the previous 3D face model methods.