• Title/Summary/Keyword: Corner feature

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Augmented Reality System using Planar Natural Feature Detection and Its Tracking (동일 평면상의 자연 특징점 검출 및 추적을 이용한 증강현실 시스템)

  • Lee, A-Hyun;Lee, Jae-Young;Lee, Seok-Han;Choi, Jong-Soo
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.48 no.4
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    • pp.49-58
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    • 2011
  • Typically, vision-based AR systems operate on the basis of prior knowledge of the environment such as a square marker. The traditional marker-based AR system has a limitation that the marker has to be located in the sensing range. Therefore, there have been considerable research efforts for the techniques known as real-time camera tracking, in which the system attempts to add unknown 3D features to its feature map, and these then provide registration even when the reference map is out of the sensing range. In this paper, we describe a real-time camera tracking framework specifically designed to track a monocular camera in a desktop workspace. Basic idea of the proposed scheme is that a real-time camera tracking is achieved on the basis of a plane tracking algorithm. Also we suggest a method for re-detecting features to maintain registration of virtual objects. The proposed method can cope with the problem that the features cannot be tracked, when they go out of the sensing range. The main advantage of the proposed system are not only low computational cost but also convenient. It can be applicable to an augmented reality system for mobile computing environment.

Discrimination between spontaneous and posed smile: Humans versus computers (자발적 웃음과 인위적 웃음 간의 구분: 사람 대 컴퓨터)

  • Eom, Jin-Sup;Oh, Hyeong-Seock;Park, Mi-Sook;Sohn, Jin-Hun
    • Science of Emotion and Sensibility
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    • v.16 no.1
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    • pp.95-106
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    • 2013
  • The study compares accuracies between humans and computer algorithms in the discrimination of spontaneous smiles from posed smiles. For this purpose, subjects performed two tasks, one was judgment with single pictures and the other was judgment with pair comparison. At the task of judgment with single pictures, in which pictures of smiling facial expression were presented one by one, subjects were required to judge whether smiles in the pictures were spontaneous or posed. In the task for judgment with pair comparison, in which two kinds of smiles from one person were presented simultaneously, subjects were to select spontaneous smile. To calculate the discrimination algorithm accuracy, 8 kinds of facial features were used. To calculate the discriminant function, stepwise linear discriminant analysis (SLDA) was performed by using approximately 50 % of pictures, and the rest of pictures were classified by using the calculated discriminant function. In the task of single pictures, the accuracy rate of SLDA was higher than that of humans. In the analysis of accuracy on pair comparison, the accuracy rate of SLDA was also higher than that of humans. Among the 20 subjects, none of them showed the above accuracy rate of SLDA. The facial feature contributed to SLDA effectively was angle of inner eye corner, which was the degree of the openness of the eyes. According to Ekman's FACS system, this feature corresponds to AU 6. The reason why the humans had low accuracy while classifying two kinds of smiles, it appears that they didn't use the information coming from the eyes enough.

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Towards 3D Modeling of Buildings using Mobile Augmented Reality and Aerial Photographs (모바일 증강 현실 및 항공사진을 이용한 건물의 3차원 모델링)

  • Kim, Se-Hwan;Ventura, Jonathan;Chang, Jae-Sik;Lee, Tae-Hee;Hollerer, Tobias
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.46 no.2
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    • pp.84-91
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    • 2009
  • This paper presents an online partial 3D modeling methodology that uses a mobile augmented reality system and aerial photographs, and a tracking methodology that compares the 3D model with a video image. Instead of relying on models which are created in advance, the system generates a 3D model for a real building on the fly by combining frontal and aerial views. A user's initial pose is estimated using an aerial photograph, which is retrieved from a database according to the user's GPS coordinates, and an inertial sensor which measures pitch. We detect edges of the rooftop based on Graph cut, and find edges and a corner of the bottom by minimizing the proposed cost function. To track the user's position and orientation in real-time, feature-based tracking is carried out based on salient points on the edges and the sides of a building the user is keeping in view. We implemented camera pose estimators using both a least squares estimator and an unscented Kalman filter (UKF). We evaluated the speed and accuracy of both approaches, and we demonstrated the usefulness of our computations as important building blocks for an Anywhere Augmentation scenario.

A Study on the Symbolism of Auspicious Animal Sculptures Installed on Woldae(月臺) Stone Railing at the Geunjeongjeon(勤政殿) of Gyeongbokgung(景福宮) - Based on Twenty-eight Mansions - (경복궁 근정전 월대 석난간에 설치된 서수 조각물의 내용 및 상징적 의미 연구 -28수 관련 내용을 중심으로-)

  • Lee, Ho-Sun;Han, Dong-Soo
    • Journal of architectural history
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    • v.29 no.2
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    • pp.75-88
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    • 2020
  • There are stone sculptures diversely shaped in several parts of Gyeongbokgung. Geunjeongjeon is a place where the stone sculptures are intensively placed among the various palace buildings of Gyeongbokgung, and it is more important because it contains the phases of the age of the dynasty and the symbolism of governing philosophy. What can be seen in the structure of auspicious animal sculptures is based on the form of instinctive thought that the heavenly and human order systems are in an organic correspondence with each other, especially with regard to astronomical events such as Samwon Sasin 12jisin 28su. The parts that have been interpreted only in Sasin and 12jisin in the interpretations such as wild dogs, Gyoryong, camels, wolves, and apes were able to clarify the contents by revealing the form of 28su. In particular, as Beopsu Ssangbeopsu at the corner may be related to the guardian deity who governs water, called Yimun, Chimi, and Chimun, it is one of Bibo's ways to protect the palace that was vulnerable to fire. In addition, the shape of the existing 28su placed Dambi, but Ha Woldae at the Geunjeongjeon was assumed to have a camel statue and a planned arrangement of double meaning with the Bibo form of Pungsu Sasinsa, and it is also a feature of the arrangement of Woldae at the Geunjeongjeon. The actual composition of auspicious animals at the Nambogye of Geunjeongjeon was in the order of Haechi, wild dogs, horses and Jujak, and the contents of "Gyeongbokgung Construction Daily Record" were in the order of Haechi, horses, wild dogs, and Jujak. As to different composition layouts, based on the contents of the "Gyeongbok palace Construction Daily Record", the composition of Samjae Cheonjiin (天地人) was interpreted differently from the conventional interpretation of the arrangement of Woldae. All of these forms are associated with defense systems in the four directions and have become animal representations of each direction. The auspicious animal statues placed on the railing of Geunjeongjeon Woldae can be seen as reflected in a single building with the three dimensional personality that includes Pungsu's Bibo personality with the symbolic meaning that reveals the centrality as Jeong Jeon, the nation's best politics let alone the ideological system of the ancient astronomical of the East called Men Heaven Unity.