• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.1390-1392
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• 2003

The arid regions of western China are currently the focus of extensive exploration and development. This paper reports on recent experience gained by Chinese and Canadian project team members in the use of a variety of Earth observation satellite imagery for oil exploration and environmental assessment exercises in the Kuche area of Xinjiang. Through careful archival data selection and more recent data acquisition schemes, we have established several time series of MODIS, Landsat and Radarsat imagery in order to obtain a better understanding for daily, seasonal as well as decadal changes of the natural environment as well as man-made environmental features.

• 대한원격탐사학회지
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• 제18권1호
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• pp.25-33
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• 2002

In 1799, Korea has become a country that holds Earth observation satellite in orbit as they had succeeded in the launch of KOPMSAT-1, the first Korean Earth observation satellite for the practical purpose. For the wide application of the satellite imagery, various application techniques are required, and topographic mapping is essential technique for the application in various fields. Moreover, considering that the main mission of the KOMPSAT-1 is to provide the satellite imagery for the mapping of Korean peninsula, the topographic mapping using KOMPSAT-1 EOC imagery is very significant. In this paper, we showed the possibility of digital plotting using KOMPSAT-1 EOC stereo images to produce topographic map. For the purpose, we implemented experimental stereo plotting using digital photogrammetric workstation and analyzed the procedure. As a result of this paper, we showed that some elements consist in 1:25,000 scale map can be plotted from KOMPSAT-1 Stereo images.

• 대한원격탐사학회지
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• 제23권3호
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• pp.199-209
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• 2007

Traditionally, aerial images have been used as main sources for compiling topographic maps. In recent years, lidar data has been exploited as another type of mapping data. Regarding their performances, aerial imagery has the ability to delineate object boundaries but omits much of these boundaries during feature extraction. Lidar provides direct information about heights of object surfaces but have limitations with respect to boundary localization. Considering the characteristics of the sensors, this paper proposes an approach to extracting buildings from lidar and aerial imagery, which is based on the complementary characteristics of optical and range sensors. For detecting building regions, relationships among elevation contours are represented into directional graphs and searched for the contours corresponding to external boundaries of buildings. For generating building models, a wing model is proposed to assemble roof surface patches into a complete building model. Then, building models are projected and checked with features in aerial images. Experimental results show that the proposed approach provides an efficient and accurate way to extract building models.

• 대한원격탐사학회지
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• 제24권5호
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• pp.517-524
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• 2008

In order to classify an satellite imagery into geospatial features of interest, the supervised classification needs to be trained to distinguish these features through training sampling. However, even though an imagery is classified, different results of classification could be generated according to operator's experience and expertise in training process. Users who practically exploit an classification result to their applications need the research accomplishment for the consistent result as well as the accuracy improvement. The experiment includes the classification results for training process used VITD polygons as a prior probability and training parameter, instead of manual sampling. As results, classification accuracy using VITD polygons as prior probabilities shows the highest results in several methods. The training using unsupervised classification with VITD have produced similar classification results as manual training and/or with prior probability.

• 대한원격탐사학회지
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• 제22권1호
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• pp.41-47
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• 2006

Detection and identification of targets from remotely sensed imagery are of great interest for civilian and military application. This paper presents an algorithm for target detection in high spatial resolution imagery based on the spectral and the dimensional characteristics of the reference target. In this algorithm, the spectral and the dimensional information of the reference target is extracted automatically from the sample image of the reference target. Then in the entire image, the candidate target pixels are extracted based on the spectral characteristics of the reference target. Finally, groups of candidate pixels which form isolated spatial objects of similar size to that of the reference target are extracted as detected targets. The experimental test results showed that even though the algorithm detected spatial objects which has different shape as targets if the spectral and the dimensional characteristics are similar to that of the reference target, it could detect 97.5% of the targets in the image. Using hyperspectral image and utilizing the shape information are expected to increase the performance of the proposed algorithm.

• 대한원격탐사학회지
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• 제22권5호
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• pp.351-356
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• 2006

Based on current practical needs for geo-spatial information on mobile platform, the main theme of this study is a design and implementation of dynamic 3D terrain rendering system using spaceborne imagery, as a kind of texture image for photo-realistic 3D scene generation on mobile environment. Image processing and 3D graphic techniques and algorithms, such as TIN-based vertex generation with regular spacing elevation data for generating 3D terrain surface, image tiling and image-vertex texturing in order to resolve limited resource of mobile devices, were applied and implemented by using graphic pipeline of OpenGL|ES (Embedded System) API. Through this implementation and its tested results with actual data sets of DEM and satellite imagery, we demonstrated the realizable possibility and adaptation of complex typed and large sized 3D geo-spatial information in mobile devices. This prototype system can be used to mobile 3D applications with DEM and satellite imagery in near future.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
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• pp.848-851
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• 2006

Green vegetation is one of the most critical factors for environment conditions thorough modulating evapotranspiration and absorption of solar radiation. Thus, fractional green vegetation cover (FVC) plays an important role in observing and managing environment. Remote sensing provides a seemingly obvious data source for quantifying FVC over large area. Therefore we compared a set of methods for estimating FVC using hyperspectral remote sensing data. For our study, we used Hyperion imagery acquired in April, 2002. In order to achieve our efforts, we analyzed simple NDVI-based method and spectral mixture analysis (SMA) models that were applied a variety of combinations of possible endmembers.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
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• pp.752-755
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• 2006

Evaportranspiration is an important factor in hydrology cycle. Traditionally, it is measured by using basin or empirical formula with meteorology data, while it does not represent the evaportranspiration over a regional area. With the advent of improved remote sensing technology, it becomes a surface parameter of research interest in the field of remote sensing. Airborne and satellite imagery are utilized in this study. The high resolution airborne images include visible, near infrared, and thermal infrared bands and the satellite images are acquired by MODIS. Surface heat fluxes such as latent heat flux and sensible heat flux are estimate by using airborne and satellite images with surface meteorological measurements. We develop a new method to estimate the evaportranspiration over the rice paddy. The surface heat fluxes are initialized with a surface energy balance concept and iterated for convergent solution with atmospheric correct functions associated with aerodynamic resistance of heat transport. Furthermore, we redistribute the total net energy into sensible heat and latent heat fluxes. The result reveals that radiation and evaporation controlled extremes can be properly decided with both airborne and satellite images. The correlation coefficient of latent heat flux and sensible heat flux with corresponding in situ observations are 0.66 and 0.76, respectively. The relative root mean squared errors (RMSEs) for latent heat flux and sensible heat flux are 97.81 $(W/m^2)$ and 124.33 $(W/m^2)$, respectively. It is also shown that the newly developed retrieval scheme performs well when it is tested by using MODIS date.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.452-455
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• 2007

3D stereoscopic viewing of large scale imagery, such as aerial photography and satellite images, needs different parallaxes relative to the display scale. For example, when a viewer sees a stereoscopic image of aerial photography, the optimal parallax of its zoom-in image should be smaller than that of its zoom-out. Therefore, relative parallax adjustment according to the display scale is required. Merely adjusting the spacing between stereo images is not appropriate because the depths of the whole image are either exaggerated or reduced entirely. This paper focuses on the improving stereoscopic viewing with a single remote sensing image and a digital surface model (DSM). We present the parallax adjustment technique to maximize the 3D realistic effect and the visual comfort. For remote sensing data, DSM height value can be regarded as disparity. There are two possible kinds of methods to adjust the relative parallax with a single image performance. One is the DSM compression technique: the other is an adjustment of the distance between the original image and its stereo-mate. In our approach, we carried out a test to evaluate the optimal distance between a single remote sensing image and its stereo-mate, relative to the viewing scale. Several synthetic stereo-mates according to certain viewing scale were created using a parallel projection model and their anaglyphs were estimated visually. The occlusion of the synthetic stereo-mate was restored by the inpainting method using the fields of experts (FoE) model. With the experiments using QuickBird imagery, we could obtain stereoscopic images with optimized parallax at varied display scales.

• 대한원격탐사학회지
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• 제34권4호
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• pp.671-680
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• 2018

Compared to the imagery produced by traditional satellites, PlanetScope satellite imagery has made it possible to easily capture remotely-sensed imagery every day through dozens or even hundreds of satellites on a relatively small budget. This study aimed to detect changed areas and update a land cover map using a PlanetScope image. To generate a classification map, pixel-based Random Forest (RF) classification was performed by using additional features, such as the Normalized Difference Water Index (NDWI) and the Normalized Difference Vegetation Index (NDVI). The classification result was converted to vector data and compared with the existing land cover map to estimate the changed area. To estimate the accuracy and trends of the changed area, the quantitative quality of the supervised classification result using the PlanetScope image was evaluated first. In addition, the patterns of the changed area that corresponded to the classification result were analyzed using the PlanetScope satellite image. Experimental results found that the PlanetScope image can be used to effectively to detect changed areas on large-scale land cover maps, and supervised classification results can update the changed areas.