• Title/Summary/Keyword: Spatial imagery

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Measuring Water Depth by Using a Combination of GPS/Echosounder (음향측심기와 위성항법을 이용한 하천의 수심 측량)

  • 정영동;강상구
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.20 no.4
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    • pp.375-381
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    • 2002
  • Depth of water information is obtained mainly from echo-sounding instrument which observes the round-trip time of signal from water surface to the bottom. Photogrammetry, underwater survey and laser survey etc. are also used as another method of bathymetric surveying. These methods are used specially for making track chart in a shallow water area. On the other hand, aircraft or satellite imagery ara also used in the sea area where the effect of suspended material is low and water quality is good. Presently, general bathymetric surveying has been performed in our country, but the spatial density of surveyed point are relatively low. Therefore, in this study we built a grid water depth chart which measured combing echosounder with GPS-RTK method and the depth accuracy was analyzed by using the data of direct survey water depth. As a results, the bathymatric mapping which use echosounder is more economical method compared to the existing methods.

Image Mosaic using Multiresolution Wavelet Analysis (다해상도 웨이블렛 분석 기법을 이용한 영상 모자이크)

  • Yang, In-Tae;Oh, Myung-Jin;Lee, In-Yeub
    • Journal of Korean Society for Geospatial Information Science
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    • v.12 no.2 s.29
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    • pp.61-66
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    • 2004
  • By the advent of the high-resolution Satellite imagery, there are increasing needs in image mosaicking technology which can be applied to various application fields such as GIS(Geographic Information system). To mosaic images, various methods such as image matching and histogram modification are needed. In this study, automated image mosaicking is performed using image matching method based on the multi-resolution wavelet analysis(MWA). Specifically, both area based and feature based matching method are embedded in the multi-resolution wavelet analysis to construct seam line.; seam points are extracted then polygon clipping method are applied to define overlapped area of two adjoining images. Before mosaicking, radiometric correction is proceeded by using histogram matching method. As a result, mosaicking area is automatically extracted by using polygon clipping method. Also, seamless image is acquired using multi-resolution wavelet analysis.

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An Analysis of Land Cover Classification Methods Using IKONOS Satellite Image (IKONOS 영상을 이용한 토지피복분류 기법 분석)

  • Kang, Nam Yi;Pak, Jung Gi;Cho, Gi Sung;Yeu, Yeon
    • Journal of Korean Society for Geospatial Information Science
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    • v.20 no.3
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    • pp.65-71
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    • 2012
  • Recently the high-resolution satellite images are helpfully using the land cover, status data for the natural resources or environment management. The effective satellite analysis process for these satellite images that require high investment can be increase the effectiveness has become increasingly important. In this Study, the statistical value of the training data is calculated and analyzed during the preprocessing. Also, that is explained about the maximum likelihood classification of traditional classification method, artificial neural network (ANN) classification method and Support Vector Machines(SVM) classification method and then the IKONOS high-resolution satellite imagery was produced the land cover map using each classification method. Each result data had to analyze the accuracy through the error matrix. The results of this study prove that SVM classification method can be good alternative of the total accuracy of about 86% than other classification method.

Automatic Measuring of GCP's Image Coordinates using Control Point Patch and Auxiliary Points Matching (기준점 패치 및 보조점 정합에 의한 지상기준점의 영상좌표 자동관측)

  • Kang, Myung-Ho;Bang, Soo-Nam;Lee, Yong-Woong
    • Journal of Korean Society for Geospatial Information Science
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    • v.11 no.2 s.25
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    • pp.29-37
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    • 2003
  • An approach is described for automatic measuring of GCP's image coordinates from SPOT imagery and focused on the fulfillment an automatic orientation of satellite images. For the orientation of a stereopair of digital images, firstly, GCP(Ground Control Point) should be selected and then the work for measuring of image coordinates correspond to GCPs is required. In this study, we propose the method for extracting the GCP's image coordinates automatically using an image patch for control points and auxiliary points matching. For the evaluation of measurement accuracy, a comparison between points those are extracted manually and automatically by a proposed method have made. Finally, we shows the feasibility of automatic image coordinates measurment by applying in stereo modeling for SPOT images.

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Application of Satellite Image Using RFM (다항식비례모형을 이용한 위성영상의 활용에 관한 연구)

  • Sohn, Hong-Gyoo;Yoo, Hyung-Uk;Park, Choung-Hwan
    • 한국지형공간정보학회:학술대회논문집
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    • 2002.11a
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    • pp.73-80
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    • 2002
  • RFM is believed to be universally applicable to any type of the sensor. Most of researches carried out lately are concentrated on terrain-independent method, but the researches about approvement of accuracy by way of terrain-dependent method are required to increase a practical use of satellite imagery in nonprofessional groups. This research focused on a means to improve RFM solution, a matching technique, and a generation of DEM through a correlation analysis, with terrain-dependent solution. The result shows that accuracy problem which is caused by over-parameterization on RFCs was removed through correlation analysis, and it was possible to generate a accurate DEM with terrain-dependent solution. And also, the application of RFM with different satellite images show sensor independent characteristics of RFM

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Acquisition of Geographic Information in North Korea Using High Resolution Satellite Image (고해상도 위성영상을 이용한 북한지역 지리정보 구축 실험연구)

  • SaGong, Hosang;Han, Sun-Hee;Park, Jin-Hyeong;Seo, Ki-Hwan
    • Journal of the Korean Association of Geographic Information Studies
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    • v.7 no.4
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    • pp.46-56
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    • 2004
  • As economic cooperation and exchanges between North and South Korea have been glowing much more than before, the demand for geographic information on North Korea is recently increasing. In fact, there is no specific method to be provided with geographic information on North Korea. In this regard, the study searched a method to collect geographic information on North Korea by using the high spatial resolution satellite image. In order to produce its best result, the study collected the geographic information on the case study area and ensured the location accuracy. This study produced total 52 items of geographic information on North Korea. Horizontal and vertical errors of stereo image, which are 4.6m and 0.9m respectively, showed high accuracy. In addition, even though the horizontal error of single image is 9m, which is bigger than that of stereo image, there is no doubt that it can be used as basic data for North Korean studies and related projects.

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Application of Highland Kimchi Cabbage Status Map for Growth Monitoring based on Unmanned Aerial Vehicle

  • Na, Sang-Il;Park, Chan-Won;Lee, Kyung-Do
    • Korean Journal of Soil Science and Fertilizer
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    • v.49 no.5
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    • pp.469-479
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    • 2016
  • Kimchi cabbage is one of the most important vegetables in Korea and a target crop for market stabilization as well. In particular Kimchi cabbages in a highland area are very sensitive to the fluctuations in supply and demand. Yield variability due to growth conditions dictates the market fluctuations of Kimchi cabbage price. This study was carried out to understand the distribution of the highland Kimchi cabbage growth status in Anbandeok. Anbandeok area in Gangneung, Gangwon-do, Korea is one of the main producing districts of highland Kimchi cabbage. The highland Kimchi cabbage status map of each growth factor was obtained from unmanned aerial vehicle (UAV) imagery and field survey data. Six status maps include UAVRGB image map, normalized difference vegetation index (NDVI) distribution/anomaly map, Crop distribution map, Planting/Harvest distribution map, Growth parameter map and Growth disorder map. As a result, the highland Kimchi cabbage status maps from May 31 to Sep. 6 in 2016 were presented to show spatial variability in the field. The benefits of the highland Kimchi cabbage status map can be summarized as follows: crop growth monitoring, reference for field observations and survey, the relative comparison of the growth condition in field scale, evaluation of growth in comparison of average year, change detection of annual crops or planting areas, abandoned fields monitoring, prediction of harvest season etc.

NDVI 시계열 시리즈에 의한 한반도 지표면 변화 추적

  • Lee, Sang-Hun
    • Proceedings of the KSRS Conference
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    • 2009.03a
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    • pp.97-100
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    • 2009
  • The surface parameters associated with the land are usually dependent on the climate, and many physical processes that are displayed in the image sensed from the land then exhibit temporal variation with seasonal periodicity. An adaptive feedback system proposed in this study reconstructs a sequence of images remotely sensed from the land surface having the physical processes with seasonal periodicity. The harmonic model is used to track seasonal variation through time, and a Gibbs random field (GRF) is used to represent the spatial dependency of digital image processes. In this study, the Normalized Difference Vegetation Index (NDVI) was computed for one week composites of the Advanced Very High Resolution Radiometer (AVHRR) imagery over the Korean peninsula for 1996 and 2000 using a dynamic technique, and the adaptive reconstruction of harmonic model was then applied to the NDVI time series for tracking changes on the ground surface. The results show that the adaptive approach is potentially very effective for continuously monitoring changes on near-real time.

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Adaptive Reconstruction of NDVI Image Time Series for Monitoring Vegetation Changes (지표면 식생 변화 감시를 위한 NDVI 영상자료 시계열 시리즈의 적응 재구축)

  • Lee, Sang-Hoon
    • Korean Journal of Remote Sensing
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    • v.25 no.2
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    • pp.95-105
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    • 2009
  • Irregular temporal sampling is a common feature of geophysical and biological time series in remote sensing. This study proposes an on-line system for reconstructing observation image series including bad or missing observation that result from mechanical problems or sensing environmental condition. The surface parameters associated with the land are usually dependent on the climate, and many physical processes that are displayed in the image sensed from the land then exhibit temporal variation with seasonal periodicity. An adaptive feedback system proposed in this study reconstructs a sequence of images remotely sensed from the land surface having the physical processes with seasonal periodicity. The harmonic model is used to track seasonal variation through time, and a Gibbs random field (GRF) is used to represent the spatial dependency of digital image processes. In this study, the Normalized Difference Vegetation Index (NDVI) image was computed for one week composites of the Advanced Very High Resolution Radiometer (AVHRR) imagery over the Korean peninsula, and the adaptive reconstruction of harmonic model was then applied to the NDVI time series from 1996 to 2000 for tracking changes on the ground vegetation. The results show that the adaptive approach is potentially very effective for continuously monitoring changes on near-real time.

Topographic Normalization of Satellite Synthetic Aperture Radar(SAR) Imagery (인공위성 레이더(SAR) 영상자료에 있어서 지형효과 저감을 위한 방사보정)

  • 이규성
    • Korean Journal of Remote Sensing
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    • v.13 no.1
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    • pp.57-73
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    • 1997
  • This paper is related to the correction of radiometric distortions induced by topographic relief. RADARSAT SAR image data were obtained over the mountainous area near southern part of Seoul. Initially, the SAR data was geometrically corrected and registered to plane rectangular coordinates so that each pixel of the SAR image has known topographic parameters. The topographic parameters (slope and aspect) at each pixel position were calculated from the digital elevation model (DEM) data having a comparable spatial resolution with the SAR data. Local incidence angle between the incoming microwave and the surface normal to terrain slope was selected as a primary geometric factor to analyze and to correct the radiometric distortions. Using digital maps of forest stands, several fields of rather homogeneous forest stands were delineated over the SAR image. Once the effects of local incidence angle on the radar backscatter were defined, the radiometric correction was performed by an empirical fuction that was derived from the relationship between the geometric parameters and mean radar backscatter. The correction effects were examined by ground truth data.