• 제목/요약/키워드: Ground truth

검색결과 301건 처리시간 0.025초

KOMPSAT-3A 위성영상과 토지피복도를 활용한 산림식생의 임상 분류법 개발 (Development of a Classification Method for Forest Vegetation on the Stand Level, Using KOMPSAT-3A Imagery and Land Coverage Map)

  • 송지용;정종철;이상훈
    • 한국환경생태학회지
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    • 제32권6호
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    • pp.686-697
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    • 2018
  • 오늘날 원격탐지기술의 발달로 인해, 산림지역과 같이 피복 분류작업이 난해한 지역을 비롯한 광범위한 지역에서의 세밀한 변화탐지를 위한 고해상도 위성영상 취득이 가능해졌다. 하지만, 고해상도 영상에 대한 시계열분석의 과정에서 많은 양의 지상 관측 데이터가 요구된다. 본 연구에서는 토지피복도를 지상 관측데이터로 활용한 위성영상 분류 방법의 가능성을 시험하였다. 연구대상지는 강원도 원주시이며, 산림지역과 시가화지역이 공존하는 공간이다. 연구 자료는 2015년 3월에 촬영된 KOMPSAT-3A 영상과 2017년도 토지피복도를 이용하여 분류를 시도하였다. 서포트벡터머신(SVM)과 랜덤포레스트(RF)의 두 가지 상이한 화소기반 분류기법을 적용하여 대상지에 대한 피복분류의 분류정확도를 비교 분석하였으며, SVM 분석의 경우 다수 분석(Majority analysis)을 후속 진행하였다. 분석대상은 산림식생만 포함한 지역과 연구대상지 전지역으로 구분하였고, 대상 면적이 협소한 습지는 분석과정에서 제외하였다. 분류 결과는 오차 행렬의 전체 정확도가 두 가지 분류대상에 대해 RF 기법이 SVM 기법보다 더 나은 것으로 나타났다. 산림지역만을 대상으로 한 경우, RF 기법이 SVM 기법에 비해 18.3% 높은 값을 나타낸 반면, 전체지역을 대상으로 한 경우는 둘 사이의 간격이 5.5%로 줄어들었다. SVM 기법에 다수 분석 (Majority analysis)을 추가로 실시한 경우, 1% 정도의 정확도 향상이 나타났다. RF 기법은 산림지역의 활엽수를 분석해 내는데 상당히 효과적이었지만, 다른 대상에 대해서는 SVM 기법이 더 나은 결과를 나타내었다. 본 연구는 고해상도 단일시기 영상에 대한 화소 기반의 분류기법을 시험한 것으로, 추후 시계열분석 및 객체기반 분류기법의 추가적인 적용으로 향상된 정확도와 신뢰도를 얻을 수 있을 것으로 판단된다. 이 연구의 방법론은 시공간적으로 고해상도 분석결과를 제공함으로써, 대면적의 토지계획에 유용할 것으로 기대된다.

A Study on the Quality of Photometric Scanning Under Variable Illumination Conditions

  • Jeon, Hyoungjoon;Hafeez, Jahanzeb;Hamacher, Alaric;Lee, Seunghyun;Kwon, Soonchul
    • International journal of advanced smart convergence
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    • 제6권4호
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    • pp.88-95
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    • 2017
  • The conventional scan methods are based on a laser scanner and a depth camera, which requires high cost and complicated post-processing. Whereas in photometric scanning method, the 3D modeling data is acquired through multi-view images. This is advantageous compared to the other methods. The quality of a photometric 3D model depends on the environmental conditions or the object characteristics, but the quality is lower as compared to other methods. Therefore, various methods for improving the quality of photometric scanning are being studied. In this paper, we aim to investigate the effect of illumination conditions on the quality of photometric scanning data. To do this, 'Moai' statue is 3D printed with a size of $600(H){\times}1,000(V){\times}600(D)$. The printed object is photographed under the hard light and soft light environments. We obtained the modeling data by photometric scanning method and compared it with the ground truth of 'Moai'. The 'Point-to-Point' method used to analyseanalyze the modeling data using open source tool 'CloudCompare'. As a result of comparison, it is confirmed that the standard deviation value of the 3D model generated under the soft light is 0.090686 and the standard deviation value of the 3D model generated under the hard light is 0.039954. This proves that the higher quality 3D modeling data can be obtained in a hard light environment. The results of this paper are expected to be applied for the acquisition of high-quality data.

휴머노이드 로봇을 위한 사람 검출, 추적 및 실루엣 추출 시스템 (Human Tracking and Body Silhouette Extraction System for Humanoid Robot)

  • 곽수영;변혜란
    • 한국통신학회논문지
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    • 제34권6C호
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    • pp.593-603
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    • 2009
  • 본 논문은 스테레오 카메라가 이동하는 환경에서 카메라 움직임을 보정하여 새로운 다수의 사람을 검출하는 방법과 검출된 사람을 추적하고, 실루엣을 추출하는 통합된 시스템을 제안한다. 제안하는 시스템은 사람 검출, 추적, 실루엣 추출 3가지 모듈로 구성되어 있으며 3가지 모듈은 카메라가 이동하는 환경을 고려한 것이다. 사람 검출 모듈에서는 카메라 움직임(egomotion) 보정을 이용한 움직이는 영역 추출 결과와 스테레오 정보를 결합하여 움직이는 객체를 검출하였으며, 추적모듈은 변위 정보가 가중된 히스토그램 알고리즘으로 검출된 객체를 추적한다. 실루엣을 추출하는 모듈은 트라이맵(trimap)을 이용하여 사람의 실루엣 부분을 대략적으로 추정하는 단계와 그래프컷(graph cut)을 적용하여 정교하게 실루엣 추출하는 단계로 이루어져 있다. 본 논문에서 제안하는 방법을 실내 환경에서 팬-틸트(pan-tilt) 스테레오 카메라로 획득한 실험데이터를 대상으로 실험한 결과 다수의 사람의 검출 및 추적, 정교한 실루엣 추출이 가능한 것을 확인하였다. 본 논문의 실루엣 추출결과는 제스처 인식이나 걸음걸이 인식 등의 다양한 분야에도 적용가능하다.

경상분지 남부지역의 지열 부존 잠재력 평가를 위한 퍼지기반 자료통합의 적용성 연구 (Applicability of Fuzzy Logic Based Data Integration to Geothermal Potential Mapping in Southern Gyeongsang Basin, Korea)

  • 박맹언;백승균;성규열
    • 자원환경지질
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    • 제40권3호
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    • pp.307-318
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    • 2007
  • 지열수의 부존은 화석열수계(fossil geothermal system)의 분포와 밀접한 연관성을 가지므로, 활발한 화석열수계에 의한 광역적인 열수변질대가 분포하는 경상분지 남부지역을 대상으로 GIS 공간통합기법을 적용한 지열 부존 잠재력을 탐사하였다. 연구방법은 화석열수계의 기원 및 분포와 관련된 지질 열수변질대, 열수형 광상 분포, 선구조 밀도, 항공자력도 등 주제도를 작성하고, 현행 온천 분포와의 상관성을 파악하여, 공간통합을 실시하였다. 그 결과 퍼지 연산자 중에서는 ${\gamma}$ 연산자(${\gamma}=0.1$)가 가장 높은 성공비율을 나타내었으며, 일부 지역에서 새로운 지열수 부존 가능성이 예상된다.

Surface Water Mapping of Remote Sensing Data Using Pre-Trained Fully Convolutional Network

  • Song, Ah Ram;Jung, Min Young;Kim, Yong Il
    • 한국측량학회지
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    • 제36권5호
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    • pp.423-432
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    • 2018
  • Surface water mapping has been widely used in various remote sensing applications. Water indices have been commonly used to distinguish water bodies from land; however, determining the optimal threshold and discriminating water bodies from similar objects such as shadows and snow is difficult. Deep learning algorithms have greatly advanced image segmentation and classification. In particular, FCN (Fully Convolutional Network) is state-of-the-art in per-pixel image segmentation and are used in most benchmarks such as PASCAL VOC2012 and Microsoft COCO (Common Objects in Context). However, these data sets are designed for daily scenarios and a few studies have conducted on applications of FCN using large scale remotely sensed data set. This paper aims to fine-tune the pre-trained FCN network using the CRMS (Coastwide Reference Monitoring System) data set for surface water mapping. The CRMS provides color infrared aerial photos and ground truth maps for the monitoring and restoration of wetlands in Louisiana, USA. To effectively learn the characteristics of surface water, we used pre-trained the DeepWaterMap network, which classifies water, land, snow, ice, clouds, and shadows using Landsat satellite images. Furthermore, the DeepWaterMap network was fine-tuned for the CRMS data set using two classes: water and land. The fine-tuned network finally classifies surface water without any additional learning process. The experimental results show that the proposed method enables high-quality surface mapping from CRMS data set and show the suitability of pre-trained FCN networks using remote sensing data for surface water mapping.

An Approach to Measurement of Water Quality Factors and its Application Using NOAA satellite Data

  • Jang, Dong-Ho;Jo, Gi-Ho;Chi, Kwang-Hoon
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 1999년도 Proceedings of International Symposium on Remote Sensing
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    • pp.363-370
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    • 1999
  • Remotely sensed data is regarded as a potentially effective data source for the measurement of water quality and for the environmental change of water bodies. In this study, we measured the spectral reflectance by using multi-spectral image of low resolution camera(LRC) which will be loaded in the OSMI multi-purpose satellite(KOMPSAT) scheduled to be launched on 1999 to use the data in analyzing water pollution. We also investigated the possibility of extraction of water quality factors in water bodies by using remotely sensed low resolution data such as NOAA/AVHRR. In this study, Shiwha-District and Sang-Sam Lake was set up as the subject areas for the study. In this part of the study, we measured the spectral reflectance of the water surface to analyze the radiance of the water bodies in low resolution spectral band and tried to analyze the water quality factors in water bodies by using radiance feature from another remotely sensed data such as NOAA/AVHRR. As the method of this study, first, we measured the spectral reflectance of the water surface by using SFOV( Single Field of View) to measure the reflectance of water quality analysis from every channel in LRC spectral band(0.4~O.9${\mu}{\textrm}{m}$). Second, we investigated the usefulness of ground truth data and the LRC data by measuring every spectral reflectance of water quality factors. Third, we analyzed water quality factors by using the radiance feature from another remotely sensed data such as NOAA/AVHRR. We carried out ratio process of what we selected Chlorophyll-a and suspended sediments as the first factors of the water quality. The results of the analysis are below. First, the amount of pollutants of Shiwha-Lake has been increasing every you since 1987 by factors of eutrophication. Second, as a result of the reflectance, Chlorophyll-a represented high spectral reflectance mainly around 0.52${\mu}{\textrm}{m}$ of green spectral band, and turbidity represented high spectral reflectance at 0.57${\mu}{\textrm}{m}$. But suspended sediments absorbed high at 0.8${\mu}{\textrm}{m}$. Third, Chlorophyll-a and suspended sediments could have a distribution chart as a result of the water quality analysis by using NOAA/AVHRR data.

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An Evaluation of ETM+ Data Capability to Provide 'Forest-Shrub land-Range' Map (A Case Study of Neka-Zalemroud Region-Mazandaran-Iran)

  • Latifi Hooman;Olade Djafar;Saroee Saeed;jalilvand Hamid
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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    • pp.403-406
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    • 2005
  • In order to evaluate the Capability of ETM+ remotely- sensed data to provide 'Forest-shrub land-Rangeland' cover type map in areas near the timberline of northern forests of Iran, the data were analyzed in a portion of nearly 790 ha located in Neka-Zalemroud region. First, ortho-rectification process was used to correct the geometric errors of the image, yielding 0/68 and 0/69 pixels of RMS. error in X and Y axis, respectively. The original and panchromatic bands were fused using PANSHARP Statistical module. The ground truth map was made using 1 ha field plots in a systematic-random sampling grid, and vegetative form of trees, shrubs and rangelands was recorded as a criteria to name the plots. A set of channels including original bands, NDVI and IR/R indices and first components of PCI from visible and infrared bands, was used for classification procedure. Pair-wise divergence through CHNSEL command was used, In order to evaluate the separability of classes and selection of optimal channels. Classification was performed using ML classifier, on both original and fused data sets. Showing the best results of $67\%$ of overall accuracy, and 0/43 of Kappa coefficient in original data set. Due to the results represented above, it's concluded that ETM+ data has an intermediate capability to fulfill the spectral variations of three form- based classes over the study area.

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Near Real Time Burnt Scars Monitoring using MODIS in Thailand

  • Tanpipat Veerachai;Honda Kiyoshi;Akaakara Siri
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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    • pp.149-152
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    • 2005
  • A new methodology to detect forest fire burnt scars at near real time using MODIS (Moderate-resolution Imaging Spectroradiometer) data is presented here with a goal of introducing a new and improved capability to detect forest fire burnt scars in Thailand. This new technology is expected to increase the efficiency and effectiveness of the forest fire tackling resources distribution and management of the country. Using MODIS data in burnt scars detection has two major advantages - high availability of data and high resolution per performance ratio. Results prove the near real time algorithm suitable and working well in order to monitor the forest fire dynamic movement. The algorithm is based on the threshold separated linear equation of burnt and un-burnt. A ground truth experiment confirms the burnt and un-burnt? areas characteristics (temperature and NDVI). A threshold line on a scatter plot of Band I and Band 2 is determined to separate the burnt from un-burnt pixels. The different threshold values of NDVI and temperature use to identify pixels' anomaly, abnormal low NDVI and high temperature. The overlay (superimpose) method is used to verify burnt pixels. Since forest fire is a dynamic phenomenon, MODIS burnt scars information is suiting well to fill in the missing temporal information of LANDSAT for the forest fire control managing strategy in Thailand. This study was conducted in the Huai-Kha-Kaeng (HKK) Wildlife Sanctuary, Thailand

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해체 및 실험적 건축가들의 기하학적 디자인 표현 특성에 관한 연구 (A Study on the Expressional characteristics of Geometrical Design in the Deconstructive and Experimental Architects)

  • 황태주
    • 한국실내디자인학회논문집
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    • 제11호
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    • pp.57-63
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    • 1997
  • In the early 20'c, scientific thoughts make a change the absolute and separate concept of space-time into relative concept of continual entity; a kind of ideal world. It suggests that the meaning of geometry as absolute truth with which has endowed human beings would changed to a relative meaning of accumulation in intellectual work on 'nature'. This cognitive changes appeared into absolute arts in 20'c like Cubism, Superematism or Constructivism. De Stijl movement which had recepted the relative concepts like Einstein's 'theory of relativity' as a developed thought from Newton-Cartesian cognition on the world. Abstration would be adequate method for expressing the dynamics and interrelationship between forms and for giving values to indivisual elements in a compositiov. This method had appeared Modern architectural form, as a common framework. The expression characteristics of geometrical design in Deconstructive and Experimental architecture were summerized in four features through the results of the analysis. First, the relation of architectural element and intertextuality is expressed in discontinuation of context and refusal of functional building. Second, the concept of trace expresses as connection of place, decomposing of excavation of trace, trace of axis, trace of fragments. Third, anti-gravity expression is there to express of open cubic, to outgrow of rectangular system, to outgrow of volume, to separate of ground connectiov. Fourth, the complex composition of abstracted geometric form is these to abstracted geometry about indefinite shape, to layer through the overlap and collage, to de-meaning and amusement of form through the pursuit of uncertainty, to indeterminate of formal meaning through operation and composition of similar form cause to the diverse of meaning.

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금북정맥 주변 산림조각의 경관생태학적 해석 (Delineating Forest Patches around the Geumbuk Mountains from a Landscape Ecological Perspective)

  • 장갑수
    • 한국조경학회지
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    • 제35권1호
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    • pp.79-87
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    • 2007
  • The objective of this study was to delineate forest patches in the cities around the Geum-buk mountains at the north of the Geum River using multiplesatellite remote sensing data. Landsat visible and near-infrared satellite images obtained at multiple dates in the growing season were used to create a forest distribution map. Fragstats 3.3 was used to get the landscape indices delineating the distribution of forest patches. Additional ground truth data was used to assess the accuracy of the classification. Factor analysis was used to get the 26 landscape indices clustered into 4 factors. Factor I was labeled as' size of forest patches', factor II as 'fragmentation of forest patches', factor III as 'shape of forest patches', and factor IV as 'complexity of forest patches'. Factor I described large patches and their core area, while others did small patches and their shape and complexity. Cities including Cheonan, Gongju, Cheongyang, and Boryeong near the main ridge of the Geumbuk Mtns. had a small number of large-sized forest patches. However, cities including Taean, Seosan, Dangjin, Hongseong near the ridge of the western Geumbuk Mtns. had a large number of small-sized forest patches. Finally, this study showed that the region near the coast line in Chung-nam province has various types of forest patches having an irregular forest edge due to the elevation and slope lower than the one of the region far from the coast line which is near the ridge of the Geum-buk Mountains. Remote sensing data were useful to understand the distribution of forest patches, and landscape indices could be keys to delineate the relationship between forest patches. And the factor analysis, which simplified 26 landscape indices into 4 landscape patterns allowed us to understand the distribution and relationship of forest patches in an easy way.