• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.81.1-81.1
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• 2016

A total solar eclipse occurs on March 9 along the path through Indonesia and the Pacific. KASI organized an expedition team for total solar eclipse observation. The main purpose of this observation is to test the coronal temperature and outflow velocity diagnostics based on filter observation, which is proposed for the next generation coronagraph. In addition, various white light observations including automatic programmed observation, manual observation, linear polarization, and time-lapse movie will be tried. We report the preliminary result of the expedition.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.5
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• pp.1-8
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• 2001

A measuring system is developed to acquire static image from rotary state through CCD camera in back light illumination by synchronizing chopper to workpiece. In image processing of acquired image, lowpass filter is very useful in view of noise removal, and optimum binary image can be made through histogram equalization which is one of the histogram technique to maximize brightness intensity between workpiece and background. After image treatment applying Laplacian operator, surface roughness is calculated by introducing conversion coefficient of pixel which edge is composed of.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.237-238
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• 2015

본 논문은 스위치 동작 듀티에 따른 등가임피던스가 광범위하게 변화 하는 벅부스트 컨버터를 이용하여 전자식, 자기식 안정기 모두 호환 가능한 LED(Light Emitting Diode) 구동회로를 제안한다. 현재 사용되는 안정기는 상용 주파수를 출력으로 가지는 자기식 안정기와 LCC 인버터를 거쳐 수십kHz 주파수 출력을 가지는 전자식 안정기가 있다. 제안 회로는 안정기출력 주파수 특성 차이를 이용하여 High Pass Filter(HPF)를 통해 전자식 또는 자기식 안정기가 연결되었음을 감지하여 서로 다른 제어방식으로 동작시킴으로써 전자식 및 자기식 안정기 모두 호환이 가능하다. 본 논문에서 제안된 회로의 우수성을 검증하기 위하여 이론적 분석 및 16.8W급 LED 구동회로에 적용한 실험결과를 제시한다.

• Bulletin of the Korean Chemical Society
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• v.5 no.1
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• pp.32-37
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• 1984

The photoreaction of 2, 3-benzo-1, 1-diphenyl (or dimethyl)-1-sila-2-cyclobutene (9 or 10) with an aldehyde or ketone results in 1:1 cycloadduct of [4 + 2] type. In the reactions of 2, 3-benzo-1, 1-dimethyl-1-sila-2-cyclobutene (10) with acetone and butanone, another 1:1 adducts (13) were also formed, respectively. The following facts indicate that the formation of adduct involves an attack of a triplet carbonyl compound on the silicon of the benzosilacyclobutene, an $S_H2$ process. (1) Even when the reaction of 9 with acetophenone was carried out under conditions such that more than 99% of incident light was absorbed only by acetophenone using the filter solution of aq. cupric sulfate, the same adduct was still formed. (2) When the reaction of 9 with acetone was carried out under oxygen atmosphere, only trace amount of adduct was formed.

• ETRI Journal
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• v.41 no.1
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• pp.32-41
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• 2019

We propose a speckle reduction technique in electronic holographic display systems, where digital micro-mirror array devices are used as spatial light modulators. By adopting a programmable filtration in a general 4-f optic configuration, it is shown that the signal spectrum components in the frequency domain of a viewing-window-based holographic display system can be selectively filtered. Compared to the widely utilized single-sideband filtration techniques in electronic holographic display systems, our proposed programmable filtration can be utilized to effectively reduce the speckles in the reconstruction of point-cloud-based computer-generated holograms. Experimental results are presented to verify our proposed concept.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2019.06a
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• pp.125-126
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• 2019

현재 상업적으로 널리 쓰이는 CCTV 용 카메라는 충분한 광량이 보장된 환경에서는 가시영역 영상을, 저조도 환경에서는 적외선 영상을 획득한다. 적외선 영상은 색채정보를 갖고 있지 않아 객체의 색채 정보를 이용하여야 하는 응용에 활용하기 어렵다. 본 논문에서는 ND 필터를 사용하여 가시광선 및 근적외선 영역의 영상정보를 분리하여 취득하는 가능성에 대한 연구를 하였다. 먼저 카메라 내부의 Hot Mirror 필터를 제거하여 가시영역 및 근적외선 신호 모두가 카메라에 들어오도록 한 후 ND 필터를 사용하여 영상을 취득한 후, 본 논문에서 제안하는 분리방식을 사용하여 가시영역 및 근적외선 영역으로 분리하였다.

• Journal of Information Processing Systems
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• v.17 no.4
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• pp.737-753
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• 2021

As the demand for high-quality rendering for mixed reality, videogame, and simulation has increased, global illumination has been actively researched. Monte Carlo path tracing can realize global illumination and produce photorealistic scenes that include critical effects such as color bleeding, caustics, multiple light, and shadows. If the sampling rate is insufficient, however, the rendered results have a large amount of noise. The most successful approach to eliminating or reducing Monte Carlo noise uses a feature-based filter. It exploits the scene characteristics such as a position within a world coordinate and a shading normal. In general, the techniques are based on the denoised pixel or sample and are computationally expensive. However, the main challenge for all of them is to find the appropriate weights for every feature while preserving the details of the scene. In this paper, we compare the recent algorithms for removing Monte Carlo noise in terms of their performance and quality. We also describe their advantages and disadvantages. As far as we know, this study is the first in the world to compare the artificial intelligence-based denoising methods for Monte Carlo rendering.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.1
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• pp.166-179
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• 2021

Recently, with the development of technology, computer vision research based on the human visual system has been actively conducted. Saliency maps have been used to highlight areas that are visually interesting within the image, but they can suffer from low performance due to external factors, such as an indistinct background or light source. In this study, existing color, brightness, and contrast feature maps are subjected to multiple shape and orientation filters and then connected to a fully connected layer to determine pixel intensities within the image based on location-based weights. The proposed method demonstrates better performance in separating the background from the area of interest in terms of color and brightness in the presence of external elements and noise. Location-based weight normalization is also effective in removing pixels with high intensity that are outside of the image or in non-interest regions. Our proposed method also demonstrates that multi-filter normalization can be processed faster using parallel processing.

• Current Optics and Photonics
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• v.6 no.3
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• pp.288-296
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• 2022

We propose and experimentally demonstrate a novel photonic compressive sensing (CS) scheme for acquiring sparse radio frequency signals with adjustable compression ratio in this paper. The sparse signal to be measured and a pseudo-random binary sequence are modulated on consecutively connected chirped pulses. The modulated pulses are compressed into short pulses after propagating through a dispersive element. A programmable optical filter based on spatial light modulator is used to realize spectral segmentation and demultiplexing. After spectral segmentation, the compressed pulses are transformed into several sub-pulses and each of them corresponds to a measurement in CS. The major advantage of the proposed scheme lies in its adjustable compression ratio, which enables the system adaptive to the sparse signals with variable sparsity levels and bandwidths. Experimental demonstration and further simulation results are presented to verify the feasibility and potential of the approach.

• Journal of Korea Multimedia Society
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• v.25 no.4
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• pp.559-567
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• 2022

The optimal shipping location is determined by measuring the volume and weights of cargo shipped to non-standard cargo carriers. Currently, workers manually measure cargo volume, but automate it to improve work inefficiency. In this paper, we proposed the method of a real-time volume calculation using LiDar sensor for automating cargo measurement of non-standard cargo. For this purpose, we utilized the statistical techniques for data preprocessing and volume calculation, also used Voxel Grid filter to light weighted of data which are appropriate in real-time calculation. We implemented the function of Normal vectors and Triangle Mesh to generate surfaces and Alpha Shapes algorithms to process 3D modeling.