• Journal of Electrical Engineering and information Science
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• v.2 no.6
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• pp.177-182
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• 1997

A visual servoing method is proposed for a robot with a camera in hand. Specifically, vanishing point features are suggested by employing a viewing model of perspective projection to calculate the relative rolling, pitching and yawing angles between the object and the camera. To compensate dynamic characteristics of the robot, desired feature trajectories for the learning of visually guided line-of-sight robot motion are obtained by measuring features by the camera in hand not in the entire workspace, but on a single linear path along which the robot moves under the control of a commercially provided function of linear motion. And then, control actions of the camera are approximately found by fuzzy-neural networks to follow such desired feature trajectories. To show the validity of proposed algorithm, some experimental results are illustrated, where a four axis SCARA robot with a B/W CCD camera is used.

• Journal of information and communication convergence engineering
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• v.2 no.1
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• pp.52-57
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• 2004

In this paper, we propose a panorama-based object tracking scheme for wide-view surveillance systems that can detect and track moving objects with a pan-tilt camera. A dynamic mosaic of the background is progressively integrated in a single image using the camera motion information. For the camera motion estimation, we calculate affine motion parameters for each frame sequentially with respect to its previous frame. The camera motion is robustly estimated on the background by discriminating between background and foreground regions. The modified block-based motion estimation is used to separate the background region. Each moving object is segmented by image subtraction from the mosaic background. The proposed tracking system has demonstrated good performance for several test video sequences.

• Journal of Korea Multimedia Society
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• v.9 no.4
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• pp.421-433
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• 2006

This paper proposes a method to insert virtual objects into a real video stream based on feature tracking and camera pose estimation from a set of single-camera video frames. To insert or modify 3D shapes to target video frames, the transformation from the 3D objects to the projection of the objects onto the video frames should be revealed. It is shown that, without a camera calibration process, the 3D reconstruction is possible using multiple images from a single camera under the fixed internal camera parameters. The proposed approach is based on the simplification of the camera matrix of intrinsic parameters and the use of projective geometry. The method is particularly useful for augmented reality applications to insert or modify models to a real video stream. The proposed method is based on a linear parameter estimation approach for the auto-calibration step and it enhances the stability and reduces the execution time. Several experimental results are presented on real-world video streams, demonstrating the usefulness of our method for the augmented reality applications.

• Journal of the Optical Society of Korea
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• v.20 no.6
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• pp.784-793
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• 2016

We present a single shot low coherence white light Hilbert phase microscopy (WL-HPM) for quantitative phase imaging of Si optoelectronic devices, i.e., Si integrated circuits (Si-ICs) and Si solar cells. White light interferograms were recorded by a color CCD camera and the interferogram is decomposed into the three colors red, green and blue. Spatial carrier frequency of the WL interferogram was increased sufficiently by means of introducing a tilt in the interferometer. Hilbert transform fringe analysis was used to reconstruct the phase map for red, green and blue colors from the single interferogram. 3D step height map of Si-ICs and Si solar cells was reconstructed at multiple wavelengths from a single interferogram. Experimental results were compared with Atomic Force Microscopy and they were found to be close to each other. The present technique is non-contact, full-field and fast for the determination of surface roughness variation and morphological features of the objects at multiple wavelengths.

• Journal of the Semiconductor & Display Technology
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• v.21 no.1
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• pp.44-49
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• 2022

The number of single-person households is increasing worldwide, and among them, the proportion of elderly single-person households is increasing. In the case of elderly single-person households, a significant portion of their leisure time is devoted to watching TV. However, if they fall asleep while watching TV without turning it off, it may be difficult to sleep well due to lights and sounds of TV, which can cause health problems such as depression and reduced immunity. Therefore, in this paper, we propose a system that automatically turns off the TV when a person watching TV falls asleep. Images are collected using the camera installed in front of the TV. Since the posture of a person watching TV varies from a sitting posture to a lying posture, the system is designed to determine whether or not to fall asleep regardless of the posture. In addition, since it becomes difficult to judge eye movements as a person moves away from the TV, a method for extending the judgmentable distance is proposed. The system model was implemented and tested using a Raspberry Pi, a monitor, an infrared sensor, and a camera. Eye movements were judged regardless of sitting or lying position, and the distance between a user and a TV was extended by about 200 cm.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.2
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• pp.109-121
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• 2020

Depth calculation of objects in a scene from images is one of the most studied processes in the fields of image processing, computer vision, and photogrammetry. Conventionally, depth is calculated using a pair of overlapped images captured at different view points. However, there have been studies to calculate depths from a single image. Theoretically, it is known to be possible to calculate depth using the diameter of CoC (Circle of Confusion) caused by defocus under the assumption of a thin lens model. Thus, this study aims to verify the validity of the thin lens model to calculate depth from edge blur amount which corresponds to the radius of CoC. For this study, a commercially available DSLR (Digital Single Lens Reflex) camera was used to capture a set of target sheets which had different edge contrasts. In order to find out the pattern of the variations of edge blur against varying combination of FD (Focusing Distance) and OD (Object Distance), the camera was set to varying FD and target sheet images were captured at varying OD under each FD. Then, the edge blur and edge displacement were estimated from edge slope profiles using a brute-force method. The experimental results show that the pattern of the variations of edge blur observed in the target images was apart from their corresponding theoretical amounts derived under the thin lens assumption but can still be utilized to calculate depth from a single image for the cases similar to the limited conditions experimented under which the tendency between FD and OD is manifest.

• The Journal of the Korea Contents Association
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• v.11 no.2
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• pp.1-12
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• 2011

Movie contents requiring multiple shootings in places need much man power and many equipments. It is more serious in the case of multiple simultaneous shootings. In the points of small broadcasting companies, it is more difficult to cope with the situation, but it is also an essential task for the variety of video contents. We propose an one-person movie production scheme based on an IP camera-based live webcasting system which makes multiple shootings in places possible. It consists of three main functions of (1) collecting multiple video streams sent from IP cameras installed in places, (2) properly distributing them to Internet, and (3) receiving and editing them including recording video. By using the proposed scheme, we can be able to remotely utilize a new framework of Single-Person/ Multiple-Camera which beyonds the conventional Single-Person/Single-Camera framework. It becomes possible to take multiple simultaneous shoots in places. We can get an advantage of saving man power and time for producing various movie contents.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.4
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• pp.305-315
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• 2020

The purpose of this study is to compare algorithms of single photo resection, which determines the exterior orientation parameters used in fields such as photogrammetry, computer vision, robotics, etc. To this end, the algorithms were compared by generating experimental data by simulating terrain based on a camera used in aerial and close-range photogrammetry. Through experiments on aerial photographic camera that was taken almost vertically, it was possible to determine the exterior orientation parameters using three ground control points, but the Procrustes algorithm was sensitive to the configuration of the ground control points. Even in experiments with a close-range amateur camera where the attitude angles of the camera change significantly, the algorithm was sensitive to the configuration of the ground control points, and the other algorithms required at least six ground control points. Through experiments with two types of cameras, it was found that cosine lawbased spatial resection shows performance similar to that of a traditional photogrammetry algorithm because the number of iterations is short and no explicit initial values are required.

• Journal of the Korean Ceramic Society
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• v.25 no.1
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• pp.73-77
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• 1988

Single crystals of kalsilite were synthesized by hydrothermal method at 420$^{\circ}C$-480$^{\circ}C$ and 100 atm-1500 atm. The crystal habits are similar to those of KLiSiO4 single crystals. The crystal structure was investigated by means of X-ray single crystal diffraction. The space group of kalsilite is P63. Phase transitiions were determined by use of DTA and high temperature X-ray Guinier camera. Phase transitions of kalsilite are summerized and discussed.

• Journal of the Korean Ceramic Society
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• v.27 no.5
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• pp.631-637
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• 1990

Lithium fluolide single crystals were grown by a floating zone method, with infrared radiation convergence type heater, which is free of contamination from the crucible wall. The crystals grown by this apparatus are 5cm in length and 5-6mm in diameter. The grown cryatal was examined by an optical microscope, XRD, Laue camera, Vickers hardness tester, and FTIR.