• Journal of the Korean Institute of Navigation
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• v.15 no.3
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• pp.25-33
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• 1991

One of the main uses for ship simulators is I the field of port design, and an increasing number of simulators, of vary in degree s of fidelity, are being used for this purpose. An essential feature of all such simulators is their visual scene, which must be of sufficient fidelity to convey the key visual cues adequately. This paper examines the ability of a number of experienced mariners to perceive speeds and distances correctly using Computer Generated Imagery visual scenes of different fidelity, compared with their performance at sea.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.8
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• pp.132-139
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• 2015

Visual SLAM(Simultaneous Localization And Mapping) has been used widely to estimate a mobile robot's location. Visual SLAM estimates relative motions with static visual features over image sequence. Because visual SLAM methods assume generally static features in the environment, we cannot obtain precise results in dynamic situation including many moving objects: cars and human beings. This paper presents a stereo vision based SLAM method in dynamic environment. First, we extract disparity map with stereo vision and compute optical flow. We then compute disparity change that is the estimated flow field between stereo views. After examining the disparity change value, we detect ROIs(Region Of Interest) in disparity space to determine dynamic scene objects. In indoor environment, many structural planes like walls may be determined as false dynamic elements. To solve this problem, we segment the scene into planar structure. More specifically, disparity values by the stereo vision are projected to X-Z plane and we employ Hough transform to determine planes. In final step, we remove ROIs nearby the walls and discriminate static scene elements in indoor environment. The experimental results show that the proposed method can obtain stable performance in dynamic environment.

• KIPS Transactions on Software and Data Engineering
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• v.4 no.4
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• pp.187-194
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• 2015

In this paper, we present an effective visual odometry estimation system to track the real-time pose of a camera moving in 3D space. In order to meet the real-time requirement as well as to make full use of rich information from color and depth images, our system adopts a feature-based sparse odometry estimation method. After matching features extracted from across image frames, it repeats both the additional inlier set refinement and the motion refinement to get more accurate estimate of camera odometry. Moreover, even when the remaining inlier set is not sufficient, our system computes the final odometry estimate in proportion to the size of the inlier set, which improves the tracking success rate greatly. Through experiments with TUM benchmark datasets and implementation of the 3D scene reconstruction application, we confirmed the high performance of the proposed visual odometry estimation method.

• The Journal of Korea Robotics Society
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• v.3 no.3
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• pp.245-254
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• 2008

Recently, many vision-based navigation methods have been introduced as an intelligent robot application. However, many of these methods mainly focus on finding an image in the database corresponding to a query image. Thus, if the environment changes, for example, objects moving in the environment, a robot is unlikely to find consistent corresponding points with one of the database images. To solve these problems, we propose a novel navigation strategy which uses fast motion estimation and a practical scene recognition scheme preparing the kidnapping problem, which is defined as the problem of re-localizing a mobile robot after it is undergone an unknown motion or visual occlusion. This algorithm is based on motion estimation by a camera to plan the next movement of a robot and an efficient outlier rejection algorithm for scene recognition. Experimental results demonstrate the capability of the vision-based autonomous navigation against dynamic environments.

• Journal of the Korean Society of Marine Environment & Safety
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• v.6 no.1
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• pp.11-22
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• 2000

The paper describes creation methods of background scenes to implement realistic virtual environments in the VRSS (Virtual Reality Ship Simulator). VRSS is next-generation system constructed with virtual tools in a virtual space. Thus, it could have many benefits compared to conventional ship simulators composed with heavy bridge mock-up system and wide visual presentations. In this work, we developed effective 3D object modeling techniques, and constructed virtual harbor scene by using 3D-Webmaster authoring tool. The virtual harbor was built with object-oriented 3D objects modeled to interact with user's action. With the immersion-type VR system, we created virtual harbor environments in a virtual space, and discussed on the naturalness of the scene with test results of SDMPA (Semantic Differential Method for Psychophysical Assessment) by 10 subjects. As the results of subject assessment, all of the participants could felt natural-like harbor. Therefore, we found that the proposed creation methods and procedures of background scene are enabling to fit to the full mission VRSS construction.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.4
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• pp.675-684
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• 1997

The bit rate control algorithm which is capable of handing scene change is proposed. In MPEG-2 TM5, block variance is used to measure block activity. But block variance is not consistent with human visual system and does not differenciate the distribution of pixel values within the block. In target bit allocation process of TM5, global complexity, obtained by results of previous coded pictures, is used. Since I pictures are spaced relatively far apart, their complexity estimate is not very accurate. In the proposed algorithm local variance is used to measure block activity and detect scene change. Local variance, using deviation from the mean of neighboring pixels, well represents the distribution of pixel values within the block. If scene change is detected, the local variance information is used for target bit allocation process. Allocating target bits for I picture, the average local variance difference between previous and current I picture is considered. The experimental results show that the proposed algorithm can detect scene change very precisely and gives better picture quality and higher PSNR values than MPEG-2 TM5.

• Journal of Broadcast Engineering
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• v.9 no.2
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• pp.131-141
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• 2004

Current binocular stereoscopic displays cause visual discomfort when objects with large disparities are present in the scene. One solution for improving visual comfort is synthetic depth-of-field processing, which simulates the characteristics of a human visual system. With this technique, visual comfort is improved by blurring portions of the background and/or foreground in the scene. However, this technique has the drawback of degrading overall image quality because the blurring is typically applied to both left and right images. To alleviate the visual discomfort, we propose a novel disparity-based asymmetrical filtering technique. Proposed technique applies the filtering to the image of one eye only, and controls the blur level according to the disparity information between stereoscopic images. We investigate the effects of this technique on stereoscopic video by measuring visual comfort and apparent sharpness. Our results indicate that disparity-based asymmetrical filtering can improve visual comfort of stereoscopic video while it maintains apparent sharpness if unfixated regions with large disparities are blurred under the appropriate filtering condition.

• International journal of advanced smart convergence
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• v.11 no.2
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• pp.88-94
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• 2022

The relationship between sound and vision was experimentally confirmed by physicist Ernst Florens Friedrich Chladni as early as the 18th century and formally entered into systematic research. With the development of emerging media technology, sound reactive type visual content is not limited to a single visual interaction based on the vibration of sound, and its visual content shows a diversified and scalable development trend according to different purposes in many fields. This study analyzes the development and changes of sound visual art contents from early stage to modernization, and analyzes the development characteristic of sound visual art content in different fields and scene environments influence by interactive media, new media technologies and devices by means of case analysis. Through this research, it is expected that the sound reactive type visual art content can continue to develop and extend in the existing fields, while explore the scalability of the application of sound reactive type visual art content in more fields.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.38 no.2
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• pp.108-117
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• 2020

This study takes the Gyeongju Historic Areas Daereungwon Area as the research object, uses the Virtual Walkthrough method for virtual experience and evaluation, the visual characteristics were analyzed. To analyze landscape visual characteristics and to find out the relationship between image factors and visual preferences, the factor analysis and multiple regression analysis were conducted. The results are as follows: the results of preference analysis of the Daereungwon Area show that the preference of scene3 where located on the western boundary of Noseo-rl tumuli got the highest score, and the preference score of scene5 where located on the western boundary of Daereungwon less than three points. The results of factor analysis of visual characteristics, three factors were analyzed: regularity factor, spatiality factor and historical factor. The analysis of variance and multiple regression analysis results of the relationship between factor scores and visual preferences show that regularity factor was analyzed as the biggest factor that affects the visual preference of the Historical-cultural landscape Daereungwon Area. Virtual Walkthrough method has a strong three-dimensional and strong production of the real landscape scene, it's an effective method in landscape analysis. The results of research provides data and information for improving the visual quality of Historical-cultural landscape and it's expected to be applied in the future of landscape planning.

• The KIPS Transactions:PartB
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• v.12B no.1 s.97
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• pp.39-46
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• 2005

In immersive virtual reality system, since virtual worlds do not supply users with sufficient spatial information af real world does, the users frequently experience clumsiness and roughness while manipulating virtual objects. To overcome this problem, we propose Visual Guider in this paper as a tool for enhancing user's visual space perception in immersive virtual worlds. The Visual Guider aids users to recognize exocentric distances between different scene points and egocentric distances from the observation point to other points in the scene fast and precisely. Its concept is imported from the rectangular grids frequently used in two-dimensional windows applications. We applied the proposed technique to an experimental virtual space implemented in $CAVE^(TM)-like$ system and tested its effectiveness while users grasp and move virtual objects.