• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2006.04a
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• pp.457-462
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• 2006

Coastline has been considered as fundamental geographic information of a nation. Recently, the coastlines of higher resolution and accuracy with less update period ever than before are increasingly required. This requirement cannot be easily satisfied with the most traditional methods based on field survey such as leveling or GPS measurements. The newly developed airborne LIDAR system can be used as a promising alternative since it rapidly acquire numerous three-dimensional points densely sampled from the terrain around the coastline. Hence, in this study we developed a nearly automatic method to extract the coastline from LIDAR data and applied it to real data to verify its performance. From the comparison of the extracted coastlines with those from a digital map, we conclude that the proposed method can provide more accurate and precise lines.

• Korean Journal of Remote Sensing
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• v.33 no.4
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• pp.437-444
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• 2017

Since land pixels often generate false alarms in ship detection using Synthetic Aperture Radar (SAR), land masking is a necessary step which can be processed by a land area map or water database. However, due to the continuous coastline changes caused by newport, bridge, etc., an updated data should be considered to mask either the land or the oceanic part of SAR. Furthermore, coastal concrete facilities make noise signals, mainly caused by side lobe effect. In this paper, we propose two methods. One is a semi-automatic water body data generation method that consists of terrain correction, thresholding, and median filter. Another is a dynamic land masking method based on water database. Based on water database, it uses a breadth-first search algorithm to find and mask noise signals from coastal concrete facilities. We verified our methods using Sentinel-1 SAR data. The result shows that proposed methods remove maximum 84.42% of false alarms.

• Journal of Korea Multimedia Society
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• v.23 no.1
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• pp.102-110
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• 2020

This study covers exploration of seabed around Heuksando Island using hover drones. To do so, we inspected the terrain of the island and set autonomous flight waypoints on each area of the island's shores. Next, we designated seabed scan radius for drones. Then the drones fitted with laser sensor hover autonomously on their assigned area and acquire seabed data. Finally, we match the seabed data on all areas according to GPS. Our final goal is to make immersive VR maritime cultural map based on 『Jasan Urbo』.

• Proceedings of the Korea Multimedia Society Conference
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• 2012.05a
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• pp.147-150
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• 2012

본 연구에서는 GIS 고도 데이터와 항공 영상 사진 정보를 이용하여 3차원 실감 지형 맵 제작 3D 에디터 개발 연구를 한다. 높이맵 방식을 이용하여 지형을 3차원화시켜 사용자에게 제공하며, 이를 위해 카메라를 기준으로 하여 보여주는 지형의 상세함을 변화시키는 상세도 레벨 설정방식으로 컴퓨터 메모리를 효율적으로 관리 할 수 있도록 하였다. 실제 지형 데이터를 이용하기 때문에 컴퓨터상에서 3차원의 실제 지형을 체험할 수 있으며 에디터 기능을 통하여 고도맵과 영상 사진만으로 간단히 실감 지도를 제작할 수 있도록 하였다.

• Proceedings of the KSRS Conference
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• v.2
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• pp.888-891
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• 2006

SAR image is not dependent on the weather condition and Sun's electromagnetic energy. But geometric distortions exist in almost all radar image, it need to be correction. The Radarsat-1 SAR images are used to monitoring of moisture acquired in May 1/1998 and May 25/1998. Radarsat-1 C band data is sensitive on moisture condition. Study area is located in Non-san site. It is made up almost agricultural area and a little of forest area. In May, Rice-planting is started in the midland of Korea. So moisture condition is undergoing many changes. Forest area need to be terrain effect removal for accurately results because it is included in layover, shadow, and so on. Results of land-cover moisture condition map are useful tool for fields of agriculture, forestry industry, and disaster.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10c
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• pp.653-655
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• 1998

본 논문은 3차원 지형을 현실감 있고 효율적으로 구축하기 위하여, 등고선 데이터로부터 지형의 특징점을 추출하고 이를 이용하여 3차원 지형 데이터를 복원하는 방법을 제안한다. 래스터 기반의 거리변환기법 알고리즘을 사용하여 2차원의 등고선 데이터로부터 3차원 지형을 생성하며, 생성된 3차원 지형정보로부터 지형의 특징점을 추출한다. 복원된 3차원 지형을 격자망 형태로 시각화하는데, 이때 특징점의 높이정보를 이용함으로써 지형을 표시하는데 요구되는 정보의 크기를 감소시킨다. 제안한 방법은 사용자가 상호대화식으로 수행할 수 있는 프로그램으로 윈도우 환경의 PC상에서 구현되었다. 이 프로그램의 실험결과는, 기존의 방법보다 적은 데이터양으로 3차원 지형을 시각화할 수 있음을 보여준다.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2010.04a
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• pp.263-266
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• 2010

The research design of the road for the LiDAR survey data was available, LiDAR data currently exists for this area Daejeon, Gongju area two map sheet selected of the LiDAR data and figures were produced using the DEM, respectively. The scale 1 / 5, 000 of figures produced by using the DEM and LiDAR DEM data comparing the results produced by the difference in some areas or That could be found. The accuracy of LiDAR data in the road design to use more accurate information on terrain, roads and construction of the linear installation cost savings Contribution will be considered.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2010.04a
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• pp.281-284
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• 2010

Recently the development of digital based measurement sensor with which a variety of surveying equipment and methods are being developed. In the field of aerial mapping using GPS, INS and Digital Camera instead of Film based Camera. In case of aerial photogrammetry for mapping, it is effective on wide area. But it is ineffective on narrow area. Therefore, the research experimented that used LiDAR sensor based mobile mapping systems for modify and update about region of Suwon and Yeouido. From these results a possibility and an effectiveness analyzed and evaluated LiDAR sensor based mobile mapping systems.

• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.2
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• pp.170-179
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• 2007

This paper introduces the optimal disposition of direction finder using EM(Electro-magnetic) wave propagation analysis which is based on LR(Longley-Rice) propagation model and the characteristics of direction finder, emitter and terrain. Initial model is simulated and modified to minimize propagation error as a result of the field trials. Proposed analysis used line-of-sight analysis and mountain-top extraction algorithm to optimize the disposition in the assigned area and the result can be displayed in the 3D map in order of the percentage coverage for direction finding possibility area.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.20 no.2
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• pp.105-110
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• 2002

For the accuracy assessment of DTM obtained by Airborne Laser Mapping Systems (ALMS), we selected 500 m spaced test points and analyze the accuracy of the DTM by various methods including GPS survey. To estimate the height at the point in between the test points of the DTM we produced a TIN, and to analyze the accuracy we use a GPS coverage map overlaid with the TIN. Compared with the existing method, DTM by ALMS is shown to be relatively accurate, and therefore, ALMS is applicable to 1/5000 digital terrain mapping.