Target Identification of Low-Resolution SAR Image via Super-Resolution

최한영 포항공과대학교 일반대학원 2022 국내석사

Resolution of synthetic aperture radar (SAR) is limited by hardware specifications of the radar and operational mode of the SAR system. The resolution is an important factor affecting SAR automatic target recognition (ATR) and low-resolution SAR images provide poor ATR performance. To solve this problem, a framework for target identification for low-resolution SAR is proposed in this thesis. We combine a spectral estimation-based super-resolution technique with deep neural network (DNN)-based ATR frameworks. The experimental results under SOCs (standard operation conditions) and EOCs (extended operation conditions) using various DNN backbones show significant improvement in identification performance for low-resolution image by the proposed framework. For the target class with significantly improved accuracy, we confirm that the unresolved scattering point in the low-resolution is successfully resolved through the method, resulting in a difference between the two classes.

Resolution target을 이용한 FT-IR imaging system의 spatial resolution 측정

강현우 인하대학교 대학원 2014 국내석사

최근에 attenuated total reflectance FT-IR imaging(ATR-FT-IR) 분석법과 low-Z particle electron probe X-ray microanalysis(low-Z particle EPMA)를 상호 보완적으로 사용하는 단일입자분석법이 개발되었다. 그러나 ATR-FT-IR imaging 측정시, ATR crystal이 시료와 직접적으로 접촉하므로, 측정 후 시료의 변형이 일어나는 단점이 있다. 반면 transmission와 reflectance FT-IR imaging 분석법은 ATR crystal을 사용하지 않으므로 시료의 변형 없이 분석 할 수 있고 시료를 다시 회수하여 다른 분석법과도 연계하여 더 많은 정보를 얻을 수 있다는 장점이 있다. 이를 바탕으로 본 연구에서는 transmission와 reflectance FT-IR imaging 분석법을 단일입자 분석에 적용하고자 그 선행연구로 FT-IR imaging 분석법의 spatial resolution을 실험적으로 측정하였다. 측정에 사용된 시료는 USAF 1951 resolution target이며, FT-IR imaging technique의 3가지 방법인 transmission, reflectance, ATR mode에서 측정하였다. 측정된 데이터로부터 Rayleigh’s criterion, edge response, MTF curve의 3가지 definition을 사용하여 spatial resolution을 얻었다. 이번 연구를 통해 FT-IR imaging technique의 3가지 방법의 spatial resolution을 실험적으로 측정하였고, ATR-FT-IR imaging 분석법 뿐만 아니라 transmission, reflectance FT-IR imaging 분석법도 low-Z particle EPMA와 연계한 단일입자 분석법에 적용할수 있을 것으로 기대된다.

Superlocalization fluorescence imaging based on plasmonic nanostructures

이원주 Graduate School, Yonsei University 2016 국내박사

Super-resolution microscopy has attracted tremendous interests in bioimaging researches. Many techniques have been developed for super-resolution imaging of live cells, intracellular proteins, bacteria, etc. It has been generally known that, using conventional fluorescence microscopy such as epifluorescence (wide-field), confocal, or total internal reflection fluorescence microscopy (TIRFM), two different subwavelength objects located within a distance of the Abbe diffraction limit cannot be distinguished from raw image obtained by charge-coupled device (CCD). The Abbe limit means that the resolution is determined by the wavelength of light and numerical aperture, generally known as almost half of the wavelength of light, i.e. 200~300 nm at a visible range. In other words, it has been a little difficult to observe sub-diffraction-limited intracellular interactions or nanoscale objects such as single molecule, virus and protein by using conventional fluorescence microscopy. Most notable imaging techniques including stimulated emission depletion (STED), structured light illumination (SIM), and single molecule localization such as photoactivated localization microscopy (PALM) and stochastic optical reconstruction microscopy (STORM) have significantly improved the resolution beyond the diffraction limit. A few tens of nanometer-scaled resolution has been reported, which leads to imaging of intracellular organisms or single molecular tracking. In this dissertation, the feasibility of plasmonic nanostructure based super-resolution imaging is explored to analyze various biological events. Nanoscale hot spots can be created at the surface of nanostructure arrays based on plasmonic field localization. Since arrayed hot spots are used for spatial sampling of biomolecules, cells, and bacteria, raw image measured by detectors can be reconstructed based on superlocalization imaging for improved image resolution below the Abbe diffraction limit. Consequently, for super-resolution imaging using subwavelength metallic nanostructures including nanograting and nanoaperture (i.e., nanohole) based on field localization, three major techniques by superlocalization sampling to obtain the sub-diffraction-limited resolution are introduced in this dissertation: (1) nanoscale localization sampling (NLS), (2) three-dimensional superlocalization imaging based on extraordinary light transmission (EOT), and (3) plasmonics-based spatially activated light microscopy (PSALM). For an NLS-based imaging technique, periodical sampling of moving targets on nanoscale was implemented using highly localized hot spots that are created on nanohole arrays based on localized surface plasmons, which leads to enhance the spatial resolution. The feasibility of NLS for sub-diffraction-limited imaging was explored to measure fluorescent monomers of microtubules gliding at the nanoaperture surface. From the reconstructed image of NLS, four times improvement in the lateral resolution was validated compared to conventional fluorescence microscopy. For three-dimensional superlocalization imaging, metallic nanoaperture arrays were also employed for EOT. Light can highly transmit through subwavelength metallic nanoapertures due to plasmon coupling. A power of imaging and sampling based on EOT is that light penetration is much deeper than that of evanescent waves under TIRFM and can be controlled by changing the aperture size. To analyze three-dimensional motion dynamics of gliding bacteria, movements of bacteria were extracted with the lateral and axial sampling precision less than 50 nm by mapping intensity variations to spatial distribution of each field spot by EOT. For PSALM, the imaging resolution is effectively determined by the distance among multiple hot spots that are formed around a nanopattern, i.e., the super-resolution can be obtained by controlling multiple light activation within a few tens of nanometers. Further studies using nanostructures based on plasmonic localization have been performed for sensing techniques as well as imaging. 최근, 초고분해능 광학 현미경은 바이오이미징 연구 분야에서 활발하게 연구되어 왔으며 이를 위한 다양한 기술들이 살아있는 세포, 세포 내 단백질, 바이러스, 박테리아 등의 영상화를 위해 개발되었다. 공초점 형광 현미경 혹은 전반사 형광 현미경과 같은 기존의 형광 영상 시스템에서는, 잘 알려진 바와 같이 아베(Abbe) 회절 한계 거리 이내에 위치한 파장 이하 크기의 서로 다른 물체가 카메라로 측정된 이미지에서는 구분될 수 없다. 이때, 분해능 한계는 빛의 파장과 개구수(開口數)에 의하여 결정되며, 가시 광 영역 대에서는 대략 빛의 반 파장, 즉 200~300 나노미터의 분해능을 갖는다. 즉, 일반적인 광학 형광 현미경을 사용하여 회절 한계 이하의 영역에서 일어나는 현상 혹은 작은 물체, 단분자, 바이러스, 단백질 등을 측정하는 것이 불가능하다. 최근 주목 받고 있는, 회절 한계 이하의 초고분해능 영상을 위한 자극 방출 억제, 구조 조명, 그리로 단일 분자 형광 기반의 이미징 기술이 전 세계적으로 활발하게 연구되고 있다. 이러한 초고분해능 광학현미경의 개발로 인해, 수 십 나노미터 스케일의 영상 분해능으로서 세포 내 유기체 혹은 단 분자 트랙킹 연구가 이뤄지고 있다. 본 논문에서는, 다양한 생물학적 현상을 관찰하고 분석하기 위한 플라즈모닉 나노구조 기반의 초고분해능 영상 시스템을 개발하고자 한다. 플라즈모닉 나노구조의 사용은 표면 전자기 필드의 국소화 현상을 유도하기 때문에, 이 때 나노구조 표면에 나노스케일 국소화 필드로서의 핫 스팟이 형성된다. 주기성을 갖는 나노구조 표면에서 발생되는 핫 스팟 어레이로부터 세포, 박테리아, 혹은 바이오 물질 등의 공간적 샘플링이 가능하기 때문에, 이러한 나노스케일 국소화 이미징을 기반으로 하여, 검출기로부터 측정 된 원시 데이터는 아베 회절 한계 이하의 분해능을 갖는 영상으로 복원 될 수 있다. 따라서 본 논문에서는, 필드 국소화 기반 파장 이하의 금속 나노격자 및 나노구멍 구조를 사용한 초고분해능 이미징을 위해, (1) 나노스케일 국소화 샘플링, (2) 특이 광 투과 현상 기반 삼차원 초고분해능 샘플링, 그리고 (3) 플라즈모닉 국소화 필드의 공간적 활성화 및 스위칭의 세 가지 주요 기술을 소개하고자 한다. 첫 번째로, 나노스케일 국소화 샘플링 기반의 이미징 기술에서는 나노구멍 어레이 구조 표면에서 발생되는 핫 스팟으로부터 측정 타겟의 움직임이 주기적 샘플링 되었으며, 이로서 공간 분해능의 향상을 유도하였다. 표면에서 글라이딩 운동을 하는 미세소관의 형광 모노머 분포 특성이 복원 된 회절 한계 이하의 분해능을 갖는 이미지로부터 측정 되었으며, 일반적인 형광 현미경과 비교하여 네 배 정도의 측면 분해능 향상 결과가 입증되었다. 필드 국소화 기반 삼차원 초고분해능 샘플링 및 이미징 기술에서는, 금속 나노구멍 어레이 구조가 표면의 특이 광 투과 현상을 유도하기 위하여 사용되었다. 파장 이하의 크기를 갖는 금속 나노구멍 구조로 입사된 빛은 플라즈모닉 커플링 현상으로 인해, 구조체를 강하게 투과할 수 있다. 이 때, 나노구멍 사이즈를 조절하여 투과 깊이를 조정할 수 있으며 전반사 형광 현미경의 소실파의 두께 보다 축 방향으로 훨씬 깊게 빛이 투과될 수 있기 때문에, 표면으로부터 깊은 영역에서 존재하는 물질 혹은 바이오 현상을 관찰할 수 있다는 이점이 있다. 측정된 형광 신호의 변동폭을 특이 광 투과 스팟 필드에 공간적으로 매핑함으로써, 박테리아의 위치 정보를 삼차원 영역에서 50 나노미터 이하의 샘플링 오차 및 정밀도로 추출하여 글라이딩 운동 특성을 분석하였다. 또한, 플라즈모닉 국소화 필드의 공간적 활성화 및 스위칭 기반 초고분해능 영상법에서는 나노패턴에서 발생하는 핫 스팟의 위치를 공간적으로 조정하면서 다중 핫 스팟을 통한 샘플링을 하기 때문에, 다중 핫 스팟 간 거리에 의하여 유효 분해능이 결정된다. 즉, 수 십 나노미터 이내의 영역에서 빛의 활성화/비활성화 제어에 따라 초고분해능 영상을 복원할 수 있게 된다. 이 밖에도 본 논문에서는 플라즈모닉 국소화 기반의 나노구조를 사용한 연구로서 이미징 뿐만 아니라 센싱 분야로의 적용 기술 또한 다루고자 한다.

Development of super-resolution microscopy towards unlimited resolution via selective deactivation of molecular transition

Doyeon Kim 고려대학교 대학원 2020 국내박사

Understanding how cells function at the subcellular level has become important. The phrase “seeing is believing” can exactly represent the scientist’s desire. They want to see the smaller and faster moving of micro-scale molecules. Microscopy is a right that technique to visualize objects and areas of objects that cannot be seen with the naked eyes. Advances in microscopy technique open the new window not only for biologist but also various experts who deal with micro-scale systems. However, the resolution of conventional optical microscopy is limited by the diffraction limit of scattered light. This limit also called the point spread function (PSF) is 200~300 nm in the x and y direction, and 450~700 nm in the axial direction. This scale is larger or similar to subcellular structures that can’t be seen by using a diffraction limited conventional microscope. To overcome the diffraction limit, super-resolution techniques have been developed in recent 20 years to visualize the biomolecular structure under few nanometer scales. Although the detailed strategies of super-resolution techniques are different from each other, they are based on the same mechanism, which uses the switching between on and off states of the target molecule’s signal. Stimulated emission depletion (STED) microscopy is one of these super-resolution techniques that impose the switching mechanism of fluorophores. STED reengineers the effective PSF by suppressing fluorescence with stimulated emission at the periphery of the confocal fluorescence PSF using donut-shaped beam. The STED microscopy can provide unlimited resolution theoretically. However, when it comes to real experimental application, STED microscopy has been reported that tends to give lower spatial resolution even when compared to STORM. The photobleaching and quenching of fluorophore induced by intense depletion beam is a severe problem that limits the resolution of the STED microscopy. Additionally, the fluorscent super-resolution microscopy methods require endogenous (e.g., fluorescence proteins) or exogenous (e.g., immunostaining) fluorophore tags. Since these tags typically have a bulky size (~ 25 nm if primary and secondary antibodies are used), they could give significant uncertainty to the localization of a target molecule. Also, exogenous tags can influence the function of biomolecules. We demonstrated the novel method to unlimited resolution, using selective deactivation of molecular transition. With the scheme of signal switch-off, that based on the idea using donut beam, we introduced super-resolution optical microscopy technique that could solve the two fundamental problems in STED microscopy: first, increasing the spatial resolution in fluorescence microscopy by combining expansion microscopy (ExM) with STED microscopy (Chapter 1-2); second, developing label-free super-resolution nonlinear vibrational microscopy technique with stimulated Raman scattering (SRS) microscopy (Chapter 3-4). Chapter 1 outlines the theoretical background for fluorescence and a brief introduction of fluorescence microscopy and conventional super-resolution microscopy techniques. Chapter 2 describes the amplified expansion stimulated emission depletion microscopy method. we developed extremely bright expansion nanoscopy by using biotin–avidin signal amplification to increase the labeling density. Our method provides up to sevenfold increases in fluorescence signal intensity in expanded samples, thus enabling the use of STED imaging with maximum depletion intensities of a commercial microscope in the order of GWcm-2. We demonstrated the method by using biotinylated antibodies and genetic incorporation approaches that allow localization of biotin in a specific molecule or organelle. Chapter 3 depicts the theoretical background and introduction for coherent nonlinear microscopy. In chapter 4, we introduce a new method for sub-diffraction Raman imaging based on depletion of stimulated Raman scattering (SRS) with label-free and theoretically unlimited depletion efficiency. The idea is based on donut-shaped depletion light as in STED microscopy. To reduce the effective focal spot of the SRS signal, it is required to find a spectroscopic process that efficiently depletes SRS signal at the periphery of the focal spot. Here, we use the three-beam femtosecond SRS scheme formulated and demonstrated to simultaneously induce two different SRS processes associated with Raman-active modes in the same molecule. Two SR gains involving a common pump pulse are coupled and compete: As one of the Stokes beam intensities increases, the other SRS is selectively suppressed. We provide a theoretical description and experimental evidence that the selective suppression behavior is due to the limited number of pump photons used for both of the two SRS processes when an intense depletion beam induces one SRS process. The maximum suppression efficiency was ∼60% with our experimental setup, where the SR gain of the ring breathing mode of benzene is the target SRS signal, which is allowed to compete with another SRS process, induced by an intense depletion beam, of the CH stretching mode. With these experimental and theoretically derived data, we expect practical biological imaging based on Raman scattering with sub-100-nm resolution.

The Role of Government in Conflict Resolution Related to Urban and Regional Development in Korea

박형서 University of Liverpool 2001 해외박사

This research started from the recognition that intergovernmental conflicts are inevitable in the process of public policy-making, and that changes in external environments have an influence on the process of conflict management and resolution. As Korean society changed in the 1990s toward democratisation and local autonomy (especially from 1995), the potential grew for intergovernmental conflicts over major urban and regional development projects. The purpose of this research has been to examine the factors influencing the intensity of such conflicts and the variables for conflict resolution related to major regional development projects and environmental issues, and in particular to consider the role of the government in the process of conflict resolution. A review of the literature on conflict theory and conflict resolution (Chs. 3 -4) identified the key factors influencing conflict origins and management of the process of conflict. It indicated the key variables influencing conflict resolution including the potential for new, more mediating roles in conflict resolution. It suggested that the degree of difficulty in resolving conflicts was related to the intensity of the conflict concerned. Further literature reviews on the introduction of local government autonomy in Korea (Ch.4) and the existing spatial planning system (Ch.5), document the growth of intergovernmental conflicts since 1995. They also verified the need for research into this general problem and provided a specific research scope in relation to major development and environmental projects in Korea so as to promote more effective management and negotiation strategies (Ch.6). The second stage of the research programme began by defining the requirements of a theoretical framework to be applied in an empirical analysis. Because of the need to investigate complex, time-extensive relationships in the specific context of Korea, the method of comparative case studies was chosen for this purpose. The main elements of the framework (Ch.7) included the factors influencing the intensity of conflict, ways of measuring the degree of intensity and the factors involved in conflict resolution. Three categories of intergovernmental conflicts were chosen for case study, and in order to provide a basis of comparison of the position before and after local autonomy (1995) two cases were examined in each category. The three categories were: nuclear plants at Amyun Island and Yongwang (Ch.8); major transport infrastructure projects at Kyungju and Inchun (Ch.9); and, water resource investment projects at Wichun and Youngwol (Ch.10). The comparative analysis is provided in Chapter 11. The case study analysis of these major development projects in Korea generally supported the central hypothesis of the relationship between the intensity of a conflict and the relative difficulty in its resolution. After the introduction of local autonomy the intensity of intergovernmental conflicts had become more visible, more intense and more difficult to resolve. Despite central government's role as a direct participant, there was some evidence of an emerging and useful mediation role which could be encouraged and developed further. The conclusions drawn from this research suggest that the key to developing a successful government role in conflict resolution in Korea will be to ensure a congruence between all elements of the planning framework, full integration and co-ordination between spatial plans or projects, and, the involvement all participants in the process of conflict resolution. There are also important roles for government in establishing new schemes for alternative dispute resolution and mechanisms for balancing between local/regional burdens and national benefits. These should be an integral part of an organisational strategy for continuous improvement in order to maximise the level of social satisfaction and competitive advantages in Korea's regional development. In terms of successful implementations of alternative approaches for conflict resolution, the outcomes for governments and people would be a better performance in conflicts related to urban and regional development.

Does spatial resolution influence the detection and attribution of extreme reduction in GPP?

김소윤 서울대학교 대학원 2018 국내석사

Climate extreme events such as drought, heat wave, and heavy rainfall have significant impacts on the terrestrial ecosystems by reducing the photosynthetic process. Due to the lack of climate and gross primary productivity datasets in fine resolution, most of the previous studies on extreme events have been conducted with coarse spatial resolution like 0.5 degree. To quantify how spatial resolutions influence the detection and attribution of extreme reduction in GPP, we used for different spatial resolutions, 5 km, 10 km, 25 km, and 50 km resolution. In this study, we deal with following two research questions 1) how does spatial resolution influence the detection of extreme reduction in GPP? 2) how does spatial resolution influence the attribution of extreme reduction in GPP? By applying the method in Zscheischler et al., (2013), we defined GPP extremes as the 3D-connected extreme reduction of GPP, which are smaller than the 1st-percentile threshold. Our results showed that 5 km, 10 km, and 25 km resolution detected 11.3%, 8.1%, and 4.4% bigger GPP reduction than 50 km resolution across the continental United States. At regional scale, total GPP reduction in the Northwest region at 5 km resolution was approximately five times bigger than that at 50 km resolution, however, that in the Great Plains and Midwest region was only increasing 3.5% and 13.0% by the change of spatial resolution from 50 km to 5 km. Interestingly, in contrast to the aforementioned results, the magnitude of spatiotemporally large connected events were rather decreasing with finer spatial resolution (the largest 50 events: 686.1 Tg C in 5 km, 709.9 Tg C in 10 km, 759.3 Tg C in 25 km, and 858.0 Tg C in 50 km resolution). The dominant climatic factor (drought) of extreme reduction in GPP was invariant to the spatial resolution. The magnitude of GPP reduction attributed to each climatic driver, however, was overestimated at the coarse spatial resolution (cold: 38.0%, hot: 21.6%, dry: 21.5%, and wet: 34.0% of relative difference, p-value < 0.1). These findings implicated that previous studies on extreme events at 0.5 degree resolution could include overestimation in quantifying the GPP reduction attributed to the climatic drivers.

Monitoring vegetation changes by enhancing the spatiotemporal resolution of satellite imagery

공주원 서울대학교 대학원 2023 국내박사

육상 생태계에서 대기권과 생물권의 상호 작용을 이해하기 위해서는 식생 변화의 모니터링이 필요하다. 이 때, 위성영상은 지표면을 관측하여 식생지도를 제공할 수 있지만, 지표변화의 상세한 정보는 구름이나 위성 이미지의 공간 해상도에 의해 제한되었다. 또한 위성영상의 시공간 해상도가 식생지도를 통한 광합성 모니터링에 미치는 영향은 완전히 밝혀지지 않았다. 본 논문에서는 고해상도 식생 지도를 일단위로 생성하기 위성 영상의 시공간 해상도를 향상시키는 것을 목표로 하였다. 고해상도 위성영상을 활용한 식생 변화 모니터링을 시공간적으로 확장하기 위해 1) 정지궤도 위성을 활용한 영상융합을 통해 시간해상도 향상, 2) 적대적생성네트워크를 활용한 공간해상도 향상, 3) 시공간해상도가 높은 위성영상을 토지피복이 균질하지 않은 공간에서 식물 광합성 모니터링을 수행하였다. 이처럼, 위성기반 원격탐지에서 새로운 기술이 등장함에 따라 현재 및 과거의 위성영상은 시공간 해상도 측면에서 향상되어 식생 변화의 모니터링 할 수 있다. 제2장에서는 정지궤도위성영상을 활용하는 시공간 영상융합으로 식물의 광합성을 모니터링 했을 때, 시간해상도가 향상됨을 보였다. 시공간 영상융합 시, 구름탐지, 양방향 반사 함수 조정, 공간 등록, 시공간 융합, 시공간 결측치 보완 등의 과정을 거친다. 이 영상융합 산출물은 경작관리 등으로 식생 지수의 연간 변동이 큰 두 장소(농경지와 낙엽수림)에서 평가하였다. 그 결과, 시공간 영상융합 산출물은 결측치 없이 현장관측을 예측하였다 (R2 = 0.71, 상대 편향 = 5.64% 농경지; R2 = 0.79, 상대 편향 = -13.8%, 활엽수림). 시공간 영상융합은 식생 지도의 시공간 해상도를 점진적으로 개선하여, 식물 생장기동안 위성영상이 현장 관측을 과소 평가를 줄였다. 영상융합은 높은 시공간 해상도로 광합성 지도를 일간격으로 생성하기에 이를 활용하여 위성 영상의 제한된 시공간 해상도로 밝혀지지 않은 식물변화의 과정을 발견하길 기대한다. 식생의 공간분포은 정밀농업과 토지 피복 변화 모니터링을 위해 필수적이다. 고해상도 위성영상으로 지구 표면을 관측하는 것을 용이하게 해졌다. 특히 Planet Fusion은 초소형위성군 데이터를 최대한 활용해 데이터 결측이 없는 3m 공간 해상도의 지표 표면 반사도이다. 그러나 과거 위성 센서(Landsat의 경우 30~60m)의 공간 해상도는 식생의 공간적 변화를 상세 분석하는 것을 제한했다. 제3장에서는 Landsat 데이터의 공간 해상도를 향상하기 위해 Planet Fusion 및 Landsat 8 데이터를 사용하여 이중 적대적 생성 네트워크(the dual RSS-GAN)를 학습시켜, 고해상도 정규화 식생 지수(NDVI)와 식물 근적외선 반사(NIRv)도를 생성하는 한다. 타워기반 현장 식생지수(최대 8년)와 드론기반 초분광지도로 the dual RSS-GAN의 성능을 대한민국 내 두 대상지(농경지와 활엽수림)에서 평가했다. The dual RSS-GAN은 Landsat 8 영상의 공간해상도를 향상시켜 공간 표현을 보완하고 식생 지수의 계절적 변화를 포착했다(R2> 0.96). 그리고 the dual RSS-GAN은 Landsat 8 식생 지수가 현장에 비해 과소 평가되는 것을 완화했다. 현장 관측에 비해 이중 RSS-GAN과 Landsat 8의 상대 편향 값 각각 -0.8% 에서 -1.5%, -10.3% 에서 -4.6% 였다. 이러한 개선은 Planet Fusion의 공간정보를 이중 RSS-GAN로 학습하였기에 가능했다. 헤당 연구 결과는 Landsat 영상의 공간 해상도를 향상시켜 숨겨진 공간 정보를 제공하는 새로운 접근 방식이다. 고해상도에서 식물 광합성 지도는 토지피복이 복잡한 공간에서 탄소 순환 모니터링시 필수적이다. 그러나 Sentinel-2, Landsat 및 MODIS와 같이 태양 동조 궤도에 있는 위성은 공간 해상도가 높거나 시간 해상도 높은 위성영상만 제공할 수 있다. 최근 발사된 초소형위성군은 이러한 해상도 한계을 극복할 수 있다. 특히 Planet Fusion은 초소형위성 자료의 시공간 해상도로 지표면을 관측할 수 있다. 4장에서, Planet Fusion 지표반사도를 이용하여 식생에서 반사된 근적외선 복사(NIRvP)를 3m 해상도 지도를 일간격으로 생성했다. 그런 다음 미국 캘리포니아주 새크라멘토-샌 호아킨 델타의 플럭스 타워 네트워크 데이터와 비교하여 식물 광합성을 추정하기 위한 NIRvP 지도의 성능을 평가하였다. 전체적으로 NIRvP 지도는 습지의 잦은 수위 변화에도 불구하고 개별 대상지의 식물 광합성의 시간적 변화를 포착하였다. 그러나 대상지 전체에 대한 NIRvP 지도와 식물 광합성 사이의 관계는 NIRvP 지도를 플럭스 타워 관측범위와 일치시킬 때만 높은 상관관계를 보였다. 관측범위를 일치시킬 경우, NIRvP 지도는 식물 광합성을 추정하는 데 있어 현장 NIRvP보다 우수한 성능을 보였다. 이러한 성능 차이는 플럭스 타워 관측범위를 일치시킬 때, 연구 대상지 간의 NIRvP-식물 광합성 관계의 기울기가 일관성을 보였기 때문이다. 본 연구 결과는 위성 관측을 플럭스 타워 관측범위와 일치시키는 것의 중요성을 보여주고 높은 시공간 해상도로 식물 광합성을 원격으로 모니터링하는 초소형위성군 자료의 잠재력을 보여준다. Monitoring changes in terrestrial vegetation is essential to understanding interactions between atmosphere and biosphere, especially terrestrial ecosystem. To this end, satellite remote sensing offer maps for examining land surface in different scales. However, the detailed information was hindered under the clouds or limited by the spatial resolution of satellite imagery. Moreover, the impacts of spatial and temporal resolution in photosynthesis monitoring were not fully revealed. In this dissertation, I aimed to enhance the spatial and temporal resolution of satellite imagery towards daily gap-free vegetation maps with high spatial resolution. In order to expand vegetation change monitoring in time and space using high-resolution satellite images, I 1) improved temporal resolution of satellite dataset through image fusion using geostationary satellites, 2) improved spatial resolution of satellite dataset using generative adversarial networks, and 3) showed the use of high spatiotemporal resolution maps for monitoring plant photosynthesis especially over heterogeneous landscapes. With the advent of new techniques in satellite remote sensing, current and past datasets can be fully utilized for monitoring vegetation changes in the respect of spatial and temporal resolution. In Chapter 2, I developed the integrated system that implemented geostationary satellite products in the spatiotemporal image fusion method for monitoring canopy photosynthesis. The integrated system contains the series of process (i.e., cloud masking, nadir bidirectional reflectance function adjustment, spatial registration, spatiotemporal image fusion, spatial gap-filling, temporal-gap-filling). I conducted the evaluation of the integrated system over heterogeneous rice paddy landscape where the drastic land cover changes were caused by cultivation management and deciduous forest where consecutive changes occurred in time. The results showed that the integrated system well predict in situ measurements without data gaps (R2 = 0.71, relative bias = 5.64% at rice paddy site; R2 = 0.79, relative bias = -13.8% at deciduous forest site). The integrated system gradually improved the spatiotemporal resolution of vegetation maps, reducing the underestimation of in situ measurements, especially during peak growing season. Since the integrated system generates daily canopy photosynthesis maps for monitoring dynamics among regions of interest worldwide with high spatial resolution. I anticipate future efforts to reveal the hindered information by the limited spatial and temporal resolution of satellite imagery. Detailed spatial representations of terrestrial vegetation are essential for precision agricultural applications and the monitoring of land cover changes in heterogeneous landscapes. The advent of satellite-based remote sensing has facilitated daily observations of the Earth’s surface with high spatial resolution. In particular, a data fusion product such as Planet Fusion has realized the delivery of daily, gap-free surface reflectance data with 3-m pixel resolution through full utilization of relatively recent (i.e., 2018-) CubeSat constellation data. However, the spatial resolution of past satellite sensors (i.e., 30–60 m for Landsat) has restricted the detailed spatial analysis of past changes in vegetation. In Chapter 3, to overcome the spatial resolution constraint of Landsat data for long-term vegetation monitoring, we propose a dual remote-sensing super-resolution generative adversarial network (dual RSS-GAN) combining Planet Fusion and Landsat 8 data to simulate spatially enhanced long-term time-series of the normalized difference vegetation index (NDVI) and near-infrared reflectance from vegetation (NIRv). We evaluated the performance of the dual RSS-GAN against in situ tower-based continuous measurements (up to 8 years) and remotely piloted aerial system-based maps of cropland and deciduous forest in the Republic of Korea. The dual RSS-GAN enhanced spatial representations in Landsat 8 images and captured seasonal variation in vegetation indices (R2 > 0.95, for the dual RSS-GAN maps vs. in situ data from all sites). Overall, the dual RSS-GAN reduced Landsat 8 vegetation index underestimations compared with in situ measurements; relative bias values of NDVI ranged from −3.2% to 1.2% and −12.4% to −3.7% for the dual RSS-GAN and Landsat 8, respectively. This improvement was caused by spatial enhancement through the dual RSS-GAN, which captured fine-scale information from Planet Fusion. This study presents a new approach for the restoration of hidden sub-pixel spatial information in Landsat images. Mapping canopy photosynthesis in both high spatial and temporal resolution is essential for carbon cycle monitoring in heterogeneous areas. However, well established satellites in sun-synchronous orbits such as Sentinel-2, Landsat and MODIS can only provide either high spatial or high temporal resolution but not both. Recently established CubeSat satellite constellations have created an opportunity to overcome this resolution trade-off. In particular, Planet Fusion allows full utilization of the CubeSat data resolution and coverage while maintaining high radiometric quality. In Chapter 4, I used the Planet Fusion surface reflectance product to calculate daily, 3-m resolution, gap-free maps of the near-infrared radiation reflected from vegetation (NIRvP). I then evaluated the performance of these NIRvP maps for estimating canopy photosynthesis by comparing with data from a flux tower network in Sacramento-San Joaquin Delta, California, USA. Overall, NIRvP maps captured temporal variations in canopy photosynthesis of individual sites, despite changes in water extent in the wetlands and frequent mowing in the crop fields. When combining data from all sites, however, I found that robust agreement between NIRvP maps and canopy photosynthesis could only be achieved when matching NIRvP maps to the flux tower footprints. In this case of matched footprints, NIRvP maps showed considerably better performance than in situ NIRvP in estimating canopy photosynthesis both for daily sum and data around the time of satellite overpass (R2 = 0.78 vs. 0.60, for maps vs. in situ for the satellite overpass time case). This difference in performance was mostly due to the higher degree of consistency in slopes of NIRvP-canopy photosynthesis relationships across the study sites for flux tower footprint-matched maps. Our results show the importance of matching satellite observations to the flux tower footprint and demonstrate the potential of CubeSat constellation imagery to monitor canopy photosynthesis remotely at high spatio-temporal resolution.

재건축결의의 요건과 문제점 및 개선방안에 관한 연구 : 법원 판례연구를 중심으로

전준용 건국대학교 부동산대학원 2009 국내석사

Prior to the enactment of the Act on the Maintenance and Improvement of Urban Areas and Dwelling Conditions for Residents(the "Urban Improvement Act"), reconstruction projects were conducted under the Act on the Ownership and Management of Aggregate Buildings (the "Aggregate Buildings Act"). The key requirement for a reconstruction project is the adoption of a ‘resolution to proceed with reconstruction’ ("Reconstruction Resolution"). If a Reconstruction Resolution is adopted, the reconstruction association can exercise the right to request the existing strata title owners who oppose the reconstruction ("Dissenting Owners") to sell their strata title ownership. The Reconstruction Resolution is required to include the strata title owners’ consent to, among others, (i) the outline of the building design, (ii) estimation of the reconstruction cost, and (iii) allocation of the reconstruction cost. Even after the enactment of the Urban Improvement Act, these requirements are still effective in the form of the ‘consent to the establishment of the reconstruction association.’ Legal disputes with respect to reconstruction projects mostly involve whether the ‘Reconstruction Resolution’ is valid and there have been many cases where the courts ruled that a Reconstruction Resolution was null and void if it failed to contain sufficient details of the ‘reconstruction cost’ and the ‘allocation of the reconstruction cost’. It is noted that it takes more than 2 to 3 years before such judicial decisions become final and binding, and that in the intervening period, the reconstruction association has proceeded, based on a project approval, with the reconstruction project in terms of payment of the relocation expenses, demolition work, etc. A court decision stating that the Reconstruction Resolution with respect to a reconstruction project is null and void poses a problem in that such decision invalidates the existing progress of such reconstruction project, which is wasteful from the society’s viewpoints. This study aims to examine (i) in how much detail the matters requiring a ‘Reconstruction Resolution’ and ‘consent’ to the establishment of the reconstruction association must be described in a Reconstruction Resolution and (ii) what is the scope of such matters, if the risk of such Reconstruction Resolution becoming invalidated is to be avoided. These are necessary to eliminate or reduce the likelihood of disputes that may arise from abstract description of such matters in such Reconstruction Resolution. This study also examines the requirements for reconstruction projects around the time of the enactment of the Urban Improvement Act, namely, (i) the outline of the building to be newly constructed after the demolition of the existing building, (ii) estimated cost of the demolition of the existing building and construction of a new building, (iii) criteria for distribution of the reconstruction cost, (iv) granting of ownership after the completion of the reconstruction project, and (v) balance between the bearing of expenses and the granting of strata title ownership. This study has derived implications from court rulings by analyzing court rulings in various cases and classifying them into those where the consent to the establishment of the reconstruction association was invalidated and those where such consent was deemed valid. Especially, the estimated reconstruction cost and distribution thereof is the most important consideration in that it is the key element based on which the strata title owners may (i) decide to participate in the reconstruction project by bearing considerable expenses or (ii) choose to sell their strata title ownership as Dissenting Owners and not to participate in the reconstruction project. The amount of the reconstruction cost to be allocated to the strata title owners or the criteria for such allocation must be determined so that the strata title owners no longer need to agree on the allocation of the reconstruction cost in the implementation phase of the reconstruction project. Although it may differ from one case to another, the important consideration for the strata title owners is that they should be provided with the ‘various prices per pyung of the property sold in lots and the amount to be borne by the members of the reconstruction association under the expected total floor space-to-ground floor ratio.’ Meanwhile, the Enforcement Rule of the Urban Improvement Act currently in effect, prescribes a ‘letter of consent form.’ However, even if such form is used, if such form fails to specifically describe the details of the ‘Reconstruction Resolution’, it is possible that such Reconstruction Resolution may be interpreted to be null and void according to the case law established by the Supreme Court of Korea. If such form is used, the form must describe, with respect to the criteria for allocation of the reconstruction cost, the information that enables the strata title owners to decide whether they want to ‘participate in the reconstruction project’, such as (i) which pyung of the newly constructed property in the reconstruction project each of the owners of the land, etc. can request to purchase in lots, (ii) how the rights of the existing owners of the land, etc. will be evaluated, (iii) what will be the price of the newly constructed property in lots, which the strata title owners may request to purchase, or what will be the ratio of such price to the valuation of the existing building, and (iv) what pyung of the newly constructed property the strata title owners may purchase in lots for free or what percentage ownership of the newly constructed property the strata title owners may be granted for free. 재건축사업은 도시및주거환경정비법(‘도시정비법’) 제정 이전에는 집합건물의소유및관리에관한법률(집합건물법)에 의해 진행되었는데, 재건축사업의 핵심요건은 ‘재건축결의’이다. 재건축결의가 있으면 조합이 재건축에 반대하는 자들에 대해 매도청구권을 행사할 수 있게 된다. 다만 이 재건축결의는 건축물설계의 개요, 비용의 개산액, 비용부담에 관한 사항 등에 대한 동의를 포함하도록 엄격하게 정해져 있다. 이러한 내용은 도시정비법 제정 이후에도 ‘조합설립 동의’의 요건으로 되었다. 재건축사업과 관련한 법률적 분쟁은 ‘재건축결의’의 무효여부가 다투어지는 것이 대부분이며, 법원은 특히 ‘비용’과 비용의 분담’에 관해 충분히 상세한 내용을 담지 않은 재건축결의는 무효라고 판단하는 예가 많았다. 그런데 이러한 판결이 확정되기까지는 2-3년 이상이 소요되고, 그 판결 확정 전에 재건축조합은 사업승인을 받아 이주비지급, 철거공사 등을 진행해 왔기 때문에 이렇게 진행된 사업을 모두 무효화시키는 것은 사회적으로 낭비이다. 본 연구의 목적은 이러한 재건축결의 내지 조합설립동의에서의 ‘결의’ 내지 ‘동의’의 대상이 되는 사항에 관하여 추상적인 기재로 인하여 발생할 수 있는 분쟁요인을 없애거나 감소시키기 위하여 ‘결의’ 내지 ‘동의’ 사항과 관련하여 어떤 내용을 그리고 어느 정도로 상세하게 기재하여야 ‘재건축결의 무효’의 위험을 방지할 수 있는지에 관한 것이다. 본 연구는 우선 도시정비법 제정 전후로 재건축사업에 있어서의 재건축결의의 요건인 ‘건설되는 건축물의 개요’, ‘건축물의 철거 및 신축에 소요되는 비용의 개략적인 금액’, ‘비용의 분담기준’, ‘사업완료후의 소유권의 귀속에 관한 사항’ 및 ‘비용분담과 구분소유권 귀속에 관한 형평성 유지’에 관하여 살펴보았고, 다수의 판례에 나타난 사안을 분석하여 조합설립 동의가 무효로 된 사안과 유효로 인정된 사안을 분류하여 그로부터 시사점을 얻었다. 특히 재건축비용의 개산액과 분담에 관한 사항은 구분소유자들로 하여금 상당한 비용을 부담하면서 재건축에 참가할 것인지, 아니면 시가에 의하여 구분소유권 등을 매도하고 재건축에 참가하지 않을 것인지를 선택하는 기준이 되는 것이므로 재건축결의에서 가장 중요한 것이다. 다만 이는 재건축의 실행단계에서 다시 비용 분담에 관한 합의를 하지 않아도 될 정도로 그 분담액 또는 산출기준을 정하여야 하는바, 구체적인 사안별로 다소 다르게 나타날 수 있지만 주요하게는 ‘여러 가지 평당 분양단가와 예상 용적율에 따른 조합원들의 분담액’이 가정적으로 제시되어야 한다는 것을 고찰했다. 한편 현행 도시정비법하에서는 시행규칙으로 ‘동의서’ 서식을 사용하도록 하고 있는바, 조합설립 동의를 위하여 이러한 서식을 사용하더라도 ‘재건축결의 사항’을 구체적으로 상세히 기재하지 않는 경우에는 대법원 판례의 기준에 따르면 무효로 해석될 여지가 있으므로 주의를 요한다. 서식을 이용할 경우에는 특히 비용의 분담기준과 관련하여 ① 각 토지등소유자들이 각자 어떤 분양평수의 신축건물에 대하여 분양신청을 할 수 있는지, ② 기존 토지등소유자의 권리가액에 대한 평가는 어떻게 이루어지는지, ③ 앞으로 신청할 신축건물의 분양가액은 어떠한지 또는 기존 건물에 대한 평가액과 대비하여 어떠한 비율로 책정되는지, ④ 무상분양평수 또는 무상지분율은 어떠한지 등과 같은 ‘재건축참여’ 여부를 판단할 수 있는 기준을 기재할 것이 요구된다고 할 것이다.

Spatial resolution limits for reconstruction of acoustic source distribution by inverse techniques

김영태 University of Southampton 2002 해외박사

One technique for deducing the strength of an acoustic source distribution from measurements of the radiated field involves the inversion of the matrix of frequency response functions relating the field measurement points to the strengths of a number of point sources used to represent the source distribution. In practice, the frequency response function matrix to be inverted may very often be ill-conditioned. This ill-conditioning will also often result in an ill-posed problem and thus regularisation algorithms are used to produce reasonable solutions. For this purpose, Tikhonov regularisation has been applied, and Generalised Cross Validation (GCV) and the L-curve method have been introduced as an effective method for determining of the proper amount of regularisation without prior knowledge of either the source distribution or the contaminating errors. In this thesis, the emphasis is placed on the relationship between the spatial resolution of the reconstructed source distribution and the small singular values of the frequency response function matrix to be inverted. However, the use of Tikhonov regularisation often suppresses the effect of small singular values and these are in turn often associated with high spatial frequencies of the source distribution. Thus the process of regularisation produces a useful estimate of the acoustic source strength distribution but with a limited spatial resolution. Furthermore, in the field of Fourier acoustics, the spatial resolution of the reconstructed source distribution is usually limited by the wavelength of the radiation. This thesis expresses the relationship between estimation accuracy, spatial resolution, noise-level and source/sensor geometry, when a range of inverse sound radiation problems are regularised using Tikhonov regularisation. The results presented form the basis of guidelines that enable the reconstruction of acoustic source strength with a resolution, under some circumstances, that is finer than the classical half-wavelength limit.

Improving image quality through enhancing spatial and spectral resolution

김한솔 Graduate School, Yonsei University 2024 국내박사

본 논문에서는 디지털 이미징 시스템을 통해 영상을 획득할 때 발생하는 열화를 극복하여 손실된 공간 해상도(Spatial resolution) 및 분광 해상도(Spectral resolution)를 복원하고 획득된 영상의 품질을 향상하는 기술에 관하여 연구한다. 영상 획득 모델에 따르면, 디지털 이미징 시스템을 통해 영상을 획득하면 워핑(Warping), 블러링(Blurring) 그리고 다운샘플링(Downsampling)의 열화 과정을 거치기 때문에 공간 해상도가 저하된 이미지가 획득된다. 신호 처리적 관점에서 해석하였을 때 이러한 열화는 블러링 과정이 영상의 고주파(High-frequency) 성분을 억제하는 저주파 통과 필터(Low-pass filter)의 역할을 수행하고, 다운샘플링 과정은 주파수 영역 정보를 서브샘플링(Sub-sampling)하여 고주파 성분을 손상하기 때문이다. 영상의 분광 해상도는 컬러 필터 배열(Color filter array)에 의해서 손상된다. 이미징 센서는 밝기 정보만을 감지할 수 있으며 색상 정보는 감지할 수 없기 때문에, 컬러 영상을 획득하기 위해서는 색상 정보를 선택적으로 투과하는 컬러 필터 배열을 사용한다. 그러나 각 화소(Pixel) 위치에서 한 가지의 색상 대역 정보만 획득할 수 있으므로, 다른 색상 대역의 정보는 획득되지 못한다. 영상 획득 과정에서 열화에 의해 손실된 공간 및 분광 해상도를 향상하는 방법으로 컬러 필터 배열에 의해 손실된 색상 정보를 복원하는 디모자이킹(Demosaicing) 기술과 여러 장의 저해상도 영상을 통해 단일 고해상도 영상을 복원하는 초해상도 영상처리(Super-resolution) 기술을 사용하였다. 먼저, RGBW 컬러 필터 배열의 전대역 채널(White channel) 정보를 활용하여 Colorization과 랭크 최소화(Rank Minimization) 방법을 번갈아 적용하여 저조도 환경에서 영상의 공간 및 분광 해상도를 복원하였다. 다음으로 멀티 프레임 Quad Bayer 컬러 필터 배열을 활용하여 영상의 공간 및 분광 해상도를 복원하였다. 프레임 사이의 전역적 움직임 정보를 추정하고 이를 바탕으로 방사형 비등방성 함수(Radial anisotropic function)를 설계하고, 선형 회귀 방법을 사용하여 영상의 공간 및 분광 해상도를 복원하였다. 마지막으로 자가 학습(Self-learning) 방법을 활용한 초해상도 영상처리 기술을 제안하였다. 제안하는 초해상도 영상복원 네트워크는 생성자가 생성한 영상을 영상 획득 모델에 따라 열화시켜 저해상도 영상을 생성하는 방법으로 외부 데이터셋이 필요하지 않은 자가 학습을 수행한다. 실험 결과에 따르면 본 논문에서 제안하는 방법은 영상의 공간 및 분광 해상도를 효과적으로 복원하고 영상의 품질을 향상하는 것으로 나타났으며, 영상의 노이즈를 제거할 수 있는 것으로 나타났다. 따라서, 저품질의 영상을 바탕으로 고품질의 영상을 획득하고자 하는 다양한 산업 분야에서 제안하는 방법을 활용할 수 있으리라 기대한다. The quality of an image acquired from a digital imaging system depends on its resolution. However, the resolution of an image, which can be categorized into spatial resolution and spectral resolution, is often degraded during the image acquisition process. First, the spectral resolution of an image captured using imaging sensors is often constrained due to the presence of the color filter array. The color filter array is a filter that selectively transmits specific spectral bands to obtain color channel information, as the imaging sensor itself can only measure brightness by counting the number of photons absorbed. While the color filter array allows the capture of specific color channels, it cannot capture the other color channels, thus making it impossible to observe the full-color image on its own. Second, the spatial resolution of an image tends to decrease due to the successive warping, blurring, and downsampling processes described in the imaging acquisition model. From a signal processing perspective, the blurring process suppresses high-frequency components as it operates as a low-pass filter. Additionally, the downsampling process introduces corruption between subsampled high-frequency components. In this dissertation, demosaicing and super-resolution techniques aimed at enhancing the resolution of the digital image are proposed. By comprehensively considering the structure of the RGBW color filter array and the Quad Bayer color filter array, a suitable demosaicing scheme is introduced. Additionally, a joint sub-pixel registration and superresolution method using multi-frame techniques is introduced. Based on self-learning scheme which does not require any external dataset and pre-training process, this method reconstructs high-resolution image from multi-frame low-resolution images. The experimental results demonstrate that the proposed method effectively improves both spatial and spectral resolution. The proposed method can be employed for obtaining high-quality images in various fields.