• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.109-111
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• 2021

Recently, computer vision research using light field cameras has been actively conducted. Since light field cameras have spatial information, various studies are being conducted in fields such as depth map estimation, super resolution, and 3D object detection. In this paper, we propose a method for detecting objects in blur images through a 7×7 array of images acquired through a light field camera. The blur image, which is weak in the existing camera, is detected through the light field camera. The proposed method uses the SSD algorithm to evaluate the performance using blur images acquired from light field cameras.

• Journal of The Korean Astronomical Society
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• v.37 no.4
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• pp.179-184
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• 2004

We have developed a wide-field imaging camera system, called WICZO, to monitor light of the night sky over extended period. Such monitoring is necessary for studying the morphology of interplanetary dust cloud and also the time and spatial variations of airglow emission. The system consists of an electric cooler a CCD camera with $60\%$ quantum efficiency at 500nm, and a fish-eye lens with $180^{\circ}$ field of view. Wide field imaging is highly desired in light of the night sky observations in general, because the zodiacal light and the airglow emission extend over the entire sky. This paper illustrates the design of WICZO, reports the result of its laboratory performance test, and presents the first night sky image, which was taken, under collaboration with Byulmaro Observatory, on top of Mt. Bongrae at Yongweol in January, 2004.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.11a
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• pp.180-181
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• 2015

In this paper, we present a consistent and efficient edit propagation method that is applied for light field data. Unlike conventional sparse edit propagation, the coherency between light field sub-aperture images is fully considered by utilizing light field consistency in the optimization framework. Instead of directly solving the optimization function on all light field sub-aperture images, the proposed optimization framework performs sparse edit propagation in the extended focus image domain. The extended focus image is the representative image that contains implicit depth information and the well-focused region of all sub-aperture images. The edit results in the extended focus image are then propagated back to each light field sub-aperture image. Experimental results on test images captured by a Lytro off-the-shelf light field camera confirm that the proposed method provides robust and consistent results of edited light field sub-aperture images.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.8
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• pp.767-773
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• 2008

This paper presents a localization system based on the use of electric compass and tracking IR light source. Digital RGB(Red, Green, Blue)signal of digital CMOS Camera is sent to CPLD which converts the color image to binary image at 30 frames per second. CMOS camera has IR filter and UV filter in front of CMOS cell. The filters cut off above 720nm light source. Binary output data of CPLD is sent to DSP that rapidly tracks the IR light source by moving Camera tilt DC motor. At a robot toward north, electric compass signals and IR light source angles which are used for calculating the data of the location system. Because geomagnetic field is linear in local position, this location system is possible. Finally, it is shown that position error is within ${\pm}1.3cm$ in this system.

• Electronics and Telecommunications Trends
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• v.33 no.2
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• pp.56-63
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• 2018

A light field (LF) is a field for expressing the intensity and direction of light reflected from a subject in a 3D space. Dual LF cameras are equipped in smart phones in Korea, mainly those by Samsung and LG. Lytro, Apple, Nvidia, MIT Media Lab, Magic Lip, and NHK are also developing LF camera technologies. LF displays are being researched by ETRI, Samsung Electronics, KIST, KAIST, SNU, MIT Media Lab, USC, HP, Apple, Microsoft, SeeReal, Musion Eyeliner, Dimenco, and Holografika.

• International journal of advanced smart convergence
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• v.10 no.2
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• pp.45-52
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• 2021

The surveillance camera market has developed and plays an important role in the field of video surveillance. However, in recent years, the identification of areas requiring surveillance has been limited by reflective light in the surveillance camera market. Cameras using polarization filters are being developed to reduce reflective light and facilitate identification. Programs are required to automatically adjust polarization filters. In this paper, we proposed an optimal angle extraction method from surveillance cameras using polarization filters through histogram analysis. First of all, transformed to grayscale to analyze the specifications of frames in multiple polarized angle images, reducing computational throughput. Then we generated and analyzed a histogram of the corresponding frame to extract the angle when the highlights are the fewest. Experiments with 0˚ and 90˚ showed high performance in extracting optimal angles. At this point, it is hoped this technology would be used for surveillance cameras in place like beach with a lot of reflective light.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2019.06a
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• pp.222-224
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• 2019

Light Field (LF) camera captures not only the light intensity but also the light direction coming to camera. While the rich information captured by LF camera enables many interesting applications such as digital refocusing, viewpoint changing, and 3D reconstruction, but it also requires powerful coding tools to reduce its large volume of data. In this paper, we investigate using the intra prediction scheme of the versatile video coding (VVC), which is the most recent video coding technology currently under developing, to compress the LF image. The Intra Block Copy (IBC) technique in VVC is exploited considering special LF image structure. The experimental result shows that VVC intra predict ion outperforms the H.265/HEVC intra coding technique in encoding LF data irrespective of using the IBC mode or not.

• Journal of Broadcast Engineering
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• v.20 no.5
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• pp.676-686
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• 2015

A 4D light field image is represented in traditional 2D spatial domain and additional 2D angular domain. The 4D light field has a resolution limitation both in spatial and angular domains since 4D signals are captured by 2D CMOS sensor with limited resolution. In this paper, we propose a dictionary learning-based superresolution algorithm in 4D light field domain to overcome the resolution limitation. The proposed algorithm performs dictionary learning using a large number of extracted 4D light field patches. Then, a high resolution light field image is reconstructed from a low resolution input using the learned dictionary. In this paper, we reconstruct a 4D light field image to have double resolution both in spatial and angular domains. Experimental result shows that the proposed method outperforms the traditional method for the test images captured by a commercial light field camera, i.e. Lytro.

• Journal of Welding and Joining
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• v.21 no.2
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• pp.102-110
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• 2003

A visual sensor consisted of polygonal mirror, laser, and CCD camera was proposed to measure the distance to the weld joint for recognizing the joint shape. To scan the laser beam of the sensor onto an object, 8-facet polygonal mirror was used as the rotating mirror. By locating the laser and the camera at axi-symmetrical positions around the mirror, the synchronized-scan condition could be satisfied even when the mirror was set to rotate through one direction continuously, which could remove the inertia effect of the conventional oscillating-mirror methods. The mathematical modelling of the proposed sensor with the optical triangulation method made it possible to derive the relation between the position of an image on the camera and the one of a laser light on the object. Through the geometrical simulation of the proposed sensor with the principal of reflection and virtual image, the optical path of a laser light could be predicted. The position and direction of the CCD camera were determined based on the Scheimpflug's condition to fit the focus of any image reflected from an object within the field of view. The results of modelling and simulation revealed that the proposed visual sensor could be used to recognize the weld joint and its vicinity located within the range of the field of view and the resolution. (Received February 19, 2003)

• Electronics and Telecommunications Trends
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• v.28 no.4
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• pp.97-106
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• 2013

기존 2D 카메라로 획득된 영상은 공간에 존재하는 빛에 대한 손실된 정보를 담고 있어 그 응용에 한계를 가지고 있다. 그러나 공간 내에 존재하는 빛 정보를 획득하여 가지고 있다면 그 공간을 똑같이 인위적으로 다른 장소에서 그대로 재현해 낼 수 있어 다양한 분야에 응용할 수 있을 것으로 기대된다. 근래에 이러한 빛 정보를 획득하기 위한 카메라 기술 및 장치들에 대한 연구개발이 활발히 진행되고 있다. 본고에서는 공간에 존재하는 빛 정보를 나타내기 위한 light field 개념을 소개하고, light field 정보 획득 카메라 기술 및 장치에 대해 살펴본다. 또한 기 개발된 light field 카메라들의 특정들을 비교 분석하고, 다양한 응용 사례에 대해 알아보기로 한다.