• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.643-647
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• 2008

ACE (Advanced Collaboration Environment) [1] aims to provide people to have remote collaboration as they are in the same Space. To provide tele-presence in remote collaboration, quality of audio and sharing of view which can show overall environment. Visual Sharing focuses on providing interactive view sharing among remote participants. A user can see remote collaboration space from any direction and can share his working screen view with others. In this paper, we summarize the development plan of Visual Sharing and relevant elementary techniques for developing Visual Sharing.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.41 no.2
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• pp.137-148
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• 2004

In this paper, we propose a new camera calibration method for rotating multi-view cameras to generate image-based panoramic 3D Virtual Environment. Since calibration accuracy worsens with an increase in distance between camera and calibration pattern, conventional camera calibration algorithms are not proper for panoramic 3D VE generation. To remedy the problem, a geometric relationship among all lenses of a multi-view camera is used for intra-camera calibration. Another geometric relationship among multiple cameras is used for inter-camera calibration. First camera parameters for all lenses of each multi-view camera we obtained by applying Tsai's algorithm. In intra-camera calibration, the extrinsic parameters are compensated by iteratively reducing discrepancy between estimated and actual distances. Estimated distances are calculated using extrinsic parameters for every lens. Inter-camera calibration arranges multiple cameras in a geometric relationship. It exploits Iterative Closet Point (ICP) algorithm using back-projected 3D point clouds. Finally, by repeatedly applying intra/inter-camera calibration to all lenses of rotating multi-view cameras, we can obtain improved extrinsic parameters at every rotated position for a middle-range distance. Consequently, the proposed method can be applied to stitching of 3D point cloud for panoramic 3D VE generation. Moreover, it may be adopted in various 3D AR applications.

• Journal of Broadcast Engineering
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• v.14 no.6
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• pp.703-720
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• 2009

This paper proposes a realistic multi-view scalable video coding scheme designed for user's interest in 3D content services and the usage in the future computing environment. Future video coding schemes should support realistic services that make users feel the 3-D presence through stereoscopic or multi-view videos, as well as to accomplish the so-called one-source multi-use services in order to comprehensively support diverse transmission environments and terminals. Unlike the most of video coding methods which only support two-dimensional display, the proposed coding scheme in this paper is the method which can support such realistic services. This paper designs and also implements the proposed coding scheme through integrating Multi-view Video Coding scheme and Scalable Video Coding scheme, then shows its possibility of realization of 3D services by the simulation. The simulation results show the proposed structure remarkably improves the performance of random access with almost the same coding efficiency.

• Proceedings of the IEEK Conference
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• 2003.11a
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• pp.187-190
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• 2003

In this paper, we propose an extrinsic calibration method for a multi-view camera to get an optimal pose in 3D space. Conventional calibration algorithms do not guarantee the calibration accuracy at a mid/long distance because pixel errors increase as the distance between camera and pattern goes far. To compensate for the calibration errors, firstly, we apply the Tsai's algorithm to each lens so that we obtain initial extrinsic parameters Then, we estimate extrinsic parameters by using distance vectors obtained from structural cues of a multi-view camera. After we get the estimated extrinsic parameters of each lens, we carry out a non-linear optimization using the relationship between camera coordinate and world coordinate iteratively. The optimal camera parameters can be used in generating 3D panoramic virtual environment and supporting AR applications.

• The Journal of Korea Robotics Society
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• v.17 no.3
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• pp.353-358
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• 2022

Due to the limited field of view of the pinhole camera, there is a lack of stability and accuracy in camera pose estimation applications such as visual SLAM. Nowadays, multiple-camera setups and large field of cameras are used to solve such issues. However, a multiple-camera system increases the computation complexity of the algorithm. Therefore, in multiple camera-assisted visual simultaneous localization and mapping (vSLAM) the multi-view tracking algorithm is proposed that can be used to balance the budget of the features in tracking and local mapping. The proposed algorithm is based on PanoSLAM architecture with a panoramic camera model. To avoid the scale issue 3D LiDAR is fused with omnidirectional camera setup. The depth is directly estimated from 3D LiDAR and the remaining features are triangulated from pose information. To validate the method, we collected a dataset from the outdoor environment and performed extensive experiments. The accuracy was measured by the absolute trajectory error which shows comparable robustness in various environments.

• The KIPS Transactions:PartD
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• v.12D no.4 s.100
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• pp.531-542
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• 2005

In this paper, we propose the MDBMS(Multi-DataBase Management System) which integrates the LDBMSs(Local DataBase Systems) with heterogeneous environment into distributed system and provides global users with rapidly query process. For designing the MDBMS, we define the functions of components and design the interaction among them. In a point of view of the global view manager in components, we describe the following 3 cases; (1)the case which the results for the global query are all stored to the global view repository, (2)the case which no result exists in the global view repository, and (3)the case which the partial results we stored to the global view repository. By comparing above cases, we establish the functionalities of our MDBMS through the sequence diagram including the interlace of among objects and the method calling. Finally, we propose the model designed in the concrete by showing the executing procedures of each function using sample query on established functions mentioned above.

• The Korean Journal of Community Living Science
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• v.19 no.4
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• pp.619-640
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• 2008

The objective of this study is to promote alternative plans on the prejudiced and distorted parts in school textbooks in the aspect of multi-functionality of agriculture and rural community. This was done through analysis of the contents in 44 kinds of schoolbooks in Korean language (30 of elementary school, 12 of middle school and 2 of high school). This will lead to promote the understanding about the multi-functionality and form the proper value system related to agriculture and rural community for children and juveniles using schoolbooks. A content analysis which is a research tool to classify all contents of materials containing the properties to become the object of interest in a systematic way, was employed to examine to what extent the contents on agriculture and rural community were reflected in the textbooks for elementary school, middle school and high school. The content analysis was done in two categories, namely; application method and function view. Application method had four types of texts, cases, figures pictures, and activities, while function view emphasized the relevance for the multi-functionality of agriculture and rural community (i.e., function of environment preservation, function of rural scenery and rural traditional culture conservation, function of maintenance and development of local society, and function of food security). The results of application method in elementary school showed that the textbook of the second-year class having a large amount of figures pictures related to agriculture and rural community, had the highest frequency in all six grades. In the function view, the environment preservation function was most abundant among a variety of multi-functionalities. In middle school, the average frequency had shown a rapid decrease. However, the function of environment preservation in the function view and the texts by application method were most frequent. in the first-year class. In high school, however, any mention related to agriculture and rural community was not made, in spite of the fact that the ten parts of textbook contained a lot of contents with a reasonable level. Based on the results of content analysis, findings and recommendations by part in textbooks for elementary school, middle school and high school have been drawn, and several examples for the content development to be included in the textbooks were listed.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2022.06a
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• pp.4-7
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• 2022

Recently, multi-view depth estimation methods using deep learning network for the 3D scene reconstruction have gained lots of attention. Multi-view video contents have various characteristics according to their camera composition, environment, and setting. It is important to understand these characteristics and apply the proper depth estimation methods for high-quality 3D reconstruction tasks. The camera setting represents the physical distance which is called baseline, between each camera viewpoint. Our proposed methods focus on deciding the appropriate depth estimation methodologies according to the characteristics of multi-view video contents. Some limitations were found from the empirical results when the existing multi-view depth estimation methods were applied to a divergent or large baseline dataset. Therefore, we verified the necessity of obtaining the proper number of source views and the application of the source view selection algorithm suitable for each dataset's capturing environment. In conclusion, when implementing a deep learning-based depth estimation network for 3D scene reconstruction, the results of this study can be used as a guideline for finding adaptive depth estimation methods.

• Proceedings of the IEEK Conference
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• 2003.11b
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• pp.115-118
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• 2003

This paper describes a system of detecting multi-views faces and estimating their face poses in an omni-directional camera environment for non-intrusive iris recognition. The paper is divided into two parts; First, moving region is identified by using difference-image information. Then this region is analyzed with face-color information to find the face candidate region. Second part is applying PCA (Principal Component Analysis) to detect multi-view faces, to estimate face pose.

• Proceedings of the IEEK Conference
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• 2003.11b
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• pp.111-114
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• 2003

In this paper, we propose a depth-based mesh modeling method to generate virtual environment. The proposed algorithm constructs mesh model from unorganized point cloud obtained from a multi-view camera. We separate the point cloud consisting objects from the background. Then, we apply triangulation to each object and background. Since the objects and the background are modeled independently, it is possible to construct effective virtual environment. The application of proposed modeling method is applicable to entertainment, such as movie and video game and effective virtual environment generation.