• Korean Journal of Optics and Photonics
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• v.28 no.6
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• pp.356-360
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• 2017

Indium tin oxide (ITO) provides high electrical conductivity and transparency at visible and near-IR wavelengths. ITO is widely used as a transparent electrode for the fabrication of LCDs, OLEDs, and many kinds of optical applications. It is widely employed for electrodes in various electric and display sectors because of its transparency in the visible range and high conductivity. Therefore, one issue is removing a specific area of a layer of material such as ITO or metallic film on a substrate, without affecting the properties of the substrate. ITO-on-glass removal using a laser is friendlier to the environment than traditional methods. In this study, ablation of ITO film on glass using a femtosecond-laser micromachining system (wavelength 1026 nm, pulse duration 150 fs) and a nanosecond-laser micromachining system (wavelength 1027 nm, pulse duration 5 ns) are described, compared, and analyzed.

• Smart Media Journal
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• v.2 no.4
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• pp.60-65
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• 2013

In this paper, we propose a high-resolution disparity map generation method using a low-resolution time-of-flight (TOF) depth camera and color camera. The TOF depth camera is efficient since it measures the range information of objects using the infra-red (IR) signal in real-time. It also quantizes the range information and provides the depth image. However, there are some problems of the TOF depth camera, such as noise and lens distortion. Moreover, the output resolution of the TOF depth camera is too small for 3D applications. Therefore, it is essential to not only reduce the noise and distortion but also enlarge the output resolution of the TOF depth image. Our proposed method generates a depth map for a color image using the TOF camera and the color camera simultaneously. We warp the depth value at each pixel to the color image position. The color image is segmented using the mean-shift segmentation method. We define a cost function that consists of color values and segmented color values. We apply a weighted average filter whose weighting factor is defined by the random walk probability using the defined cost function of the block. Experimental results show that the proposed method generates the depth map efficiently and we can reconstruct good virtual view images.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.89-89
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• 2000

AlN 박막은 Al과 N원자의 부분적 이온결합 특성을 가진 공유결합을 한 육방정계의 wurtzite 경정구조의 화합물 반도체로서, III-V족 반도체 중 가장 큰 에너지 갭(6.2 eV), 결정 구조적 이방성, 화학 양론적 결합구조, 높은 탄성종과 전달속도(약 10$\times$106 m/s)와 높은 열전도도, 고온 안정성, 가시광성.적외선 영역에서의 좋은 투과성과 높은 굴절률, 상온 대기압에서의 유일하게 안정적인 특성을 가지고 있어, 절연재료, 내열재료, 저주파 영역 센서의 압전 트랜스듀서, 광전소자, 탄성파 소자 및 내환경 소자, MIS소자 등으로 주목받고 있다. 본 연구에서는 BAW 공진기의 활용을 목적으로 반응성 마그네트론 스퍼터링 방법으로 AIN 압전박막을 제작하여, 증착 조건-질소 농도, 고주파 출력, 전체 스퍼터링 압력, 기판 온도-에 대한 박막의 특성을 조사하였다. AlN 박막의 c축 우선 방위 결정성 및 낮은 투과성, 적당한 굴절률의 특성이 BAW 공진기의 활용을 위한 요건이므로, 각각의 증착 조건하에 제작된 박막은 XRD의 $\theta$/2$\theta$ 스캔 회절상에 의한 결정성의 분석과 우선 성장 결정면의 rocking curve 및 XRD로 측정한 FWHM과 표준 편차로 결정성의 배열성과 소자 응용가능성을 조사하였다. 박막의 표면.단면 미세 구조 및 평활도는 SEM으로 관찰하였으며, Al-N 결합 상태는 XPS와 FT-IR로 분석 조사하였다. 제작된 AlN 박막의 결정성 분석 결과, c축 우선 방위 성장을 위한 스퍼터링 압력에 대한 임계 질소 농도와 임계 스퍼터링 압력이 관찰되었다. 전체 스퍼터링 압력이 6~8 mTorr의 범위에서 나타난 최소 임계질소 농도는 10%, 최대 임계 질소 농도는 60%이며, 4 m Torr 이하 10 m Torr 이상의 전체 스퍼터링 압력에서 박막의 우선 방위성장이 제재된다. 이는 AlN 박막이 형성에 관여하는 질소 이온 양의 충분한 형성에 필요로 하는 질소 가스의 유입량에 따른 것으로 판단된다. AlN 박막의 c축 결정면인 (002) 결정면의 성장을 유도하며 다른 방향으로의 성장을 제어하여 소자 활용에 유용한 박막을 제작하기 위한 고주파 출력은 300W 정도가 적당하며, 기판을 가열하지 않았을 때 낮은 투과도를 나타낸다. 본 연구에 의한 BAW 공진기 활용을 위한 AlN 압전박막의 제작을 위한 최적 증착 조건은 기판의 가열 없이 6~8 mTorr의 전체 스퍼터링 압력에 20~25%의 질소종도, 300W의 고주파 출력이다. 최적 조건에서의 AlN 박막은 약 0.19$^{\circ}$의 FWHM과 약 0.08$^{\circ}$의 표준편차를 가지며, 균일하고 조밀한 표면 미세구조와 주상정 구조의 측면구조, 파장에 대한 약 2.0의 굴절률, 낮은 투과도와 화학 양론적 구조를 가지는 우수한 박막이 형성되었다.

• Korean Journal of Remote Sensing
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• v.31 no.2
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• pp.137-148
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• 2015

The National Institute of Meteorological Research (NIMR) has operated the Fourier Transform InfraRed (FTIR) spectrometer which is the Atmospheric Emitted Radiance Interferometer (AERI) in Anmyeon island, Korea since June 2010. The ground-based AERI with similar hyper-spectral infrared sensor to satellite could be an alternative way to validate satellite-based remote sensing. In this regard, the NIMR has focused on the improvement of retrieval quality from the AERI, particularly cloud-data filtering method. The AERI spectrum which is measured on a typical clear day is selected reference spectrum and we used region of atmospheric window. We performed test of threshold in order to select valid threshold. We retrieved methane using new method which is used reference spectrum, and the other method which is used KLAPS cloud cover information, each retrieved methane was compared with that of ground-based in-situ measurements. The quality of AERI methane retrievals of new method was significantly more improved than method of used KLAPS. In addition, the comparison of vertical total column of methane from AERI and GOSAT shows good result.

• Korean Journal of Remote Sensing
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• v.31 no.5
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• pp.409-419
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• 2015

The Atmospheric Emitted Radiance Interferometer (AERI) which is the Fourier Transform InfraRed (FTIR) spectrometer has been operated by the National Institute of Meteorological Research (NIMR) in Anmyeon island, South Korea since June 2010. The ground-based AERI with similar hyper-spectral infrared sensor to satellite could be an alternative way to validate satellite-based remote sensing. In this regard, the NIMR has focused on the improvement of Cloud data Filtering Method (CFM) which employed only one reference spectrum of clear sky in winter season. This study suggests Seasonal-Cloud data Filtering Method (S-CFM) which applied seasonal AERI reference spectra. For the comparison of applied S-CFM and CFM, the methane retrievals (surface volume mixing ratio) from AERI spectra are used. The quality of AERI methane retrieval applied S-CFM was significantly more improved than that of CFM. The positive result of S-CFM is similar pattern with the seasonal variation of methane from ground-based in-situ measurement, even if the summer season's methane is retrieved over-estimation. In addition, the comparison of vertical total column of methane from AERI and GOSAT shows good result except for the summer season.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.39 no.4
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• pp.223-233
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• 2021

Systematic and continuous monitoring and management of the energy consumption of buildings are important for estimating building energy efficiency, and ultimately aim to cope with climate change and establish effective policies for environment, and energy supply and demand policies. Globally, buildings consume 36% of total energy and account for 39% of carbon dioxide emissions. The purpose of this study is to generate three-dimensional thermo-spatial building models with photogrammetric technique using drone TIR (Thermal Infrared) images to measure the temperature emitted from a building, that is essential for the building energy rating system. The aerial triangulation was performed with both optical and TIR images taken from the sensor mounted on the drone, and the accuracy of the models was analyzed. In addition, the thermo-spatial models of temperature distribution of the buildings in three-dimension were visualized. Although shape of the objects 3D building modeling is relatively inaccurate as the spatial and radiometric resolution of the TIR images are lower than that of optical images, TIR imagery could be used effectively to measure the thermal energy of the buildings based on spatial information. This paper could be meaningful to present extension of photogrammetry to various application. The energy consumption could be quantitatively estimated using the temperature emitted from the individual buildings that eventually would be uses as essential information for building energy efficiency rating system.

• Journal of the Korea Society of Computer and Information
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• v.27 no.5
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• pp.1-9
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• 2022

Localization systems can be used with various circumstances like measuring population movement and rescue technology, even in security technology (like infiltration detection system). Vision sensors such as camera often used for localization is susceptible with light and temperature, and can cause invasion of privacy. In this paper, we used ultra-wideband radar technology (which is not limited by aforementioned problems) and machine learning techniques to measure the number and location of occupants in other indoor spaces behind the wall. We used four different algorithms and compared their results, including extremely randomized tree for four different situations; detect the number of occupants in a classroom, split the classroom into 28 locations and check the position of occupant, select one out of the 28 locations, divide it into 16 fine-grained locations, and check the position of occupant, and checking the positions of two occupants (existing in different locations). Overall, four algorithms showed good results and we verified that detecting the number and location of occupants are possible with high accuracy using machine learning. Also we have considered the possibility of service expansion using the oneM2M standard platform and expect to develop more service and products if this technology is used in various fields.

• Journal of the Korean Society of Radiology
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• v.17 no.5
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• pp.679-684
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• 2023

Venous puncture is widely used to obtain blood samples for pathological examination. Because the invasive venipuncture method using a needle is repeatedly performed, the pain suffered by the patient increases, so our research team pre-developed a miniaturized near-infrared (NIR) imaging system in advance. To improve the image quality of the acquired NIR images, this study aims to model the non-local means (NLM) algorithm, which is well known to be efficient in noise reduction, and analyze its applicability in the system. The developed NIR imaging system is based on the principle that infrared rays pass through dichroic and long-pass filters and are detected by a CMOS sensor module. The proposed NLM algorithm is modeled based on the principle of replacing the pixel from which noise is to be removed with a value that reflects the distances between surrounding pixels. After acquiring an NIR image with a central wavelength of 850 nm, the NLM algorithm was applied to segment the final vein area through histogram equalization. As a result, the coefficient of variation of the NIR image of the vein using the NLM algorithm was 0.247 on average, which was an excellent result compared to conventional filtering methods. In addition, the dice similarity coefficient value of the NLM algorithm was improved by 62.91 and 9.40%, respectively, compared to the median filter and total variation methods. In conclusion, we demonstrated that the NLM algorithm can acquire accurate segmentation of veins acquired with a NIR imaging system.

• Korean Journal of Remote Sensing
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• v.37 no.6_1
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• pp.1631-1645
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• 2021

This research aims to provide the characteristics of the world's first active lidar sensor Atmospheric Laser Doppler Instrument (ALADIN) wind data and Geostationary Korea Multi Purpose Satellite 2A (GK2A) Atmospheric Motion Vector (AMV) data by comparing two wind data. As a result of comparing the data from September 2019 to August 1, 2020, The total number of collocated data for the AMV (using IR channel) and Mie channel ALADIN data is 177,681 which gives the Root Mean Square Error (RMSE) of 3.73 m/s and the correlation coefficient is 0.98. For a more detailed analysis, Comparison result considering altitude and latitude, the Normalized Root Mean Squared Error (NRMSE) is 0.2-0.3 at most latitude bands. However, the upper and middle layers in the lower latitudes and the lower layer in the southern hemispheric are larger than 0.4 at specific latitudes. These results are the same for the water vapor channel and the visible channel regardless of the season, and the channel-specific and seasonal characteristics do not appear prominently. Furthermore, as a result of analyzing the distribution of clouds in the latitude band with a large difference between the two wind data, Cirrus or cumulus clouds, which can lower the accuracy of height assignment of AMV, are distributed more than at other latitude bands. Accordingly, it is suggested that ALADIN wind data in the southern hemisphere and low latitude band, where the error of the AMV is large, can have a positive effect on the numerical forecast model.