• 한국환경과학회지
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• 제15권12호
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• pp.1141-1154
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• 2006

Orographic effect is one of the important factors to induce Local circulations and to make atmospheric turbulence, so it is necessary to use the exact topographic data for prediction of local circulations. In order to clarify the sensitivity of the spatial resolution of topography data, numerical simulations using several topography data with different spatial resolution are carried out under stable and unstable synoptic conditions. The results are as follows: 1) Influence of topographic data resolution on local circulation tends to be stronger at simulation with fine grid than that with coarse grid. 2) The hight of mountains in numerical model become mote reasonable with high resolution topographic data, so the orographic effect is also emphasized and clarified when the topographic data resolution is higher. 2) The higher the topographic resolution is, the stronger the mountain effect is. When used topographic data resolution become fine, topography in numerical model becomes closer to real topography. 3) The topographic effect tends to be stronger when atmospheric stability is strong stable. 4) Although spatial resolution of topographic data is not fundamental factor for dramatic improvement of weather prediction accuracy, some influence on small scale circulation can be recognized, especially in fluid dynamic simulation.

• 한국융합학회논문지
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• 제11권12호
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• pp.15-22
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• 2020

본 논문은 채널 강조(Channel Attentin)와 공간 강조(Spatial Attention) 방법을 결합한 딥 러닝 기반의 초해상도 방법을 제안하였다. 초해상도 과정에서 질감, 특징과 같은 주변 픽셀의 변화량이 큰 고주파 성분의 복원이 중요하다. 채널 강조와 공간 강조를 결합한 특징 강조를 이용한 초해상도 방법을 제안하였다. 기존의 CNN(Convolutional Neural Network) 기반의 초해상도 방법은 깊은 네트워크의 학습이 어려우며, 고주파 성분의 강조가 부족하여 윤곽선이 흐려지거나 왜곡이 발생한다. 문제를 해결하기 위해 스킵-커넥션(Skip Connection)을 적용한 채널 강조와 공간 강조를 결합한 강조 블록과 잔차 블록(Residual Block)을 사용하였다. 방법으로 추출한 강조된 특징 맵을 부-픽셀 컨볼루션(Sub-pixel Convolution)을 통해 특징맵을 확장하여 초해상도를 진행하였다. 이를 통해 기존의 SRCNN과 비교하여 약 PSNR는 5%, SSIM은 3% 향상되었으며 VDSR과 비교를 통해 약 PSNR는 2%, SSIM은 1% 향상된 결과를 보였다.

• 한국멀티미디어학회논문지
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• 제24권2호
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• pp.178-185
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• 2021

Three-dimensional high-resolution magnetic resonance imaging (MRI) provides fine-level anatomical information for disease diagnosis. However, there is a limitation in obtaining high resolution due to the long scan time for wide spatial coverage. Therefore, in order to obtain a clear high-resolution(HR) image in a wide spatial coverage, a super-resolution technology that converts a low-resolution(LR) MRI image into a high-resolution is required. In this paper, we propose a super-resolution technique through filter learning based on information on the surrounding gradient information in 3D space from 3D MRI images. In the learning step, the gradient features of each voxel are computed through eigen-decomposition from 3D patch. Based on these features, we get the learned filters that minimize the difference of intensity between pairs of LR and HR images for similar features. In test step, the gradient feature of the patch is obtained for each voxel, and the filter is applied by selecting a filter corresponding to the feature closest to it. As a result of learning 100 T1 brain MRI images of HCP which is publicly opened, we showed that the performance improved by up to about 11% compared to the traditional interpolation method.

• 대한원격탐사학회지
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• 제33권6_1호
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• pp.961-970
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• 2017

위성을 이용한 에어로졸 원격탐사에서 높은 공간해상도의 정보에 대한 요구가 많았음에도 그동안 단일화소가 갖는 물리적인 에어로졸 신호의 약화와 구름 등에 의한 오차 증가로 인해 산출에 어려움을 겪어왔다. 본 연구에서는 GOCI 자료를 이용하여 한-미 협력 국내 대기질 공동조사 캠페인 기간인 2016년 5, 6월에 대해 GOCI의 최대 공간 해상도인 500 m에서 고해상도 에어로졸 광학 깊이를 산출하였다. 기존의 GOCI 알고리즘은 6 km 해상도로 에어로졸 산출물을 제공해왔으며, 이번 연구에서 개발한 고해상도 산출 알고리즘은 기존 알고리즘을 기반으로 한다. 에어로졸 모형, 조견표 구성 및 역추산 과정은 동일하게 이용되었으나, 높은 해상도에서의 구름 제거 방법이 개선되었다. 그 결과, 몇 가지 사례에 대하여 6 km 산출물과 비교하였을 때 500 m 산출물의 분포 및 크기는 유사하게 나타났으나 공간 해상도가 높기 때문에 더 많은 화소에 대하여 산출되었다. 이에 따라 작은 규모의 구름 주위에서도 산출이 되었고, 에어로졸의 공간적인 변화를 세밀하게 살펴볼 수 있었다. 정확도 검증을 위하여 지상 관측 장비와 비교를 하였을 때 공간해상도가 크게 좋아졌음에도 상관 계수가 0.76, 기대 오차 내에 들어오는 비율이 51.1%로 6 km 산출물과 유사한 검증 결과를 보였다.

• 대한원격탐사학회지
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• 제35권6_4호
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• pp.1391-1401
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• 2019

KOMPSAT-3A는 2015년 한국항공우주연구원(KARI)이 발사한 고해상 광학위성으로 0.55 m 급 전정색영상(PAN), 2.2 m 급 다중 분광 영상(MS) 그리고 5.5 m 급 중적외선 영상(MIR_OR)을 제공한다. 그러나 보안 또는 군사적인 문제로 인해 공간 해상도 5.5 m MIR_OR 영상은 33 m 공간해상도로 down-sampling된 MIR_rd 영상으로 제공된다. 본 연구에서는 가상의 고주파(HP) 영상과 최적 융합 계수를 이용하여 MIR_rd 영상의 공간해상도를 복원하는 방법을 제안하였다. MS 영상과 MIR_rd 영상을 이용하여 가상의 MIR_OR^fus 영상을 제작하였으며, 이를 실제 MIR_OR 영상과 비교 분석하였다. 실험 결과, 제안된 방법이 MS 영상의 공간해상도와 MIR_rd 영상의 분광정보를 효과적으로 조합 하였다는 것을 보여주었다.

• 대기
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• 제25권2호
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• pp.283-294
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• 2015

For urban flash flood simulation, we need the higher resolution radar rainfall than radar rainfall of KMA, which has 10 min time and 1km spatial resolution, because the area of subbasins is almost below $1km^2$. Moreover, we have to secure the high quantitative accuracy for considering the urban hydrological model that is sensitive to rainfall input. In this study, we developed the quantitative precipitation estimation (QPE), which has 250 m spatial resolution and high accuracy using KMA AWS and SK Planet stations with Mt. Gwangdeok radar data in Seoul area. As the results, the rainfall field using KMA AWS (QPE1) is showed high smoothing effect and the rainfall field using Mt. Gwangdeok radar is lower estimated than other rainfall fields. The rainfall field using KMA AWS and SK Planet (QPE2) and conditional merged rainfall field (QPE4) has high quantitative accuracy. In addition, they have small smoothed area and well displayed the spatial variation of rainfall distribution. In particular, the quantitative accuracy of QPE4 is slightly less than QPE2, but it has been simulated well the non-homogeneity of the spatial distribution of rainfall.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1999년도 Proceedings of International Symposium on Remote Sensing
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• pp.122-126
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• 1999

The imaging characteristics of a 2-D interferometric synthetic aperture radiometer, such as an angular resolution, depend largely on the type of an antenna array. In this paper, different array configurations of antenna are studied and compared with each array types to get more high resolution image in spatial. T-, X- and Y- types of antenna array are considered and the performances of each type are analyzed considering spatial resolution. The simulation results of candidate antenna types are presented in this paper. In case of Y-type the coverage area of the visibility function is wide and the angular resolution is high more than the others. X-type array shows the good performance for side lobe level.

• 한국GIS학회:학술대회논문집
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• 한국GIS학회 2003년도 추계학술대회논문집
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• pp.23-29
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• 2003

Detection in remotely sensed images can be conducted spatially, spectrally or both [2]. If the images have high spatial resolution, materials can be detected by using spatial and spectral information, unless we can't see the object embedded in a pixel. In this paper, we intend to solve the limit of spatial resolution by using the hyperspectral image which has high spectral resolution. Therefore, the Linear Spectral Mixing(LSM) Model which is sub-pixel detection algorithm is used to solve this problem. To find class Endmembers, we applied Geometric Model with MNF(Minimum Noise Fraction) transformation. From the result of sub-pixel detection algorithm, we can see the detection of water is satisfied and the object shape cannot be extracted but the possibility of material existence can be identified.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.275-279
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• 2002

Change Detection is a useful technology that can be applied to various fields, taking temporal change information with the comparison and analysis among multi-temporal satellite images. Especially, Change Detection that utilizes high-resolution satellite imagery can be implemented to extract useful change information for many purposes, such as the environmental inspection, the circumstantial analysis of disaster damage, the inspection of illegal building, and the military use, which cannot be achieved by low- or middle-resolution satellite imagery. However, because of the special characteristics that result from high-resolution satellite imagery, it cannot use a pixel-based method that is used for low-resolution satellite imagery. Therefore, it must be used a feature-based algorithm based on the geographical and morphological feature. This paper presents the system that builds the change map by digitizing the boundary of the changed object. In this system, we can make the change map using manual or semi-automatic digitizing through the user interface implemented with a floating window that enables to detect the sign of the change, such as the construction or dismantlement, more efficiently.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.343-345
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• 2003

This paper describes the system development for the Ground Control Point collection and management through the major coastline region in KOREA, which will collect and manage the ground control point based on high resolution satellite image database. The module of this system is following 1) GCP/Coarstline research plan module 2) GCP/Coarstline ground collection module 3) GCP/Coarstline post processing module Our team developed the core components of ‘High Resolution Satellite Image Processing Technique’ project, and this system, among applications of our project, is constructed to apply to practical use. In this application, you will also see how to apply core components of our project.