• Journal of the Korean earth science society
• /
• 제26권7호
• /
• pp.691-697
• /
• 2005

Recently, the development of accurate gravity-meter and GPS make it possible to obtain high resolution gravity data. Though gravity data interpretation like modeling and inversion has significantly improved, gravity data processing itself has improved very little. Conventional gravity data processing removes gravity effects due to mass and height difference between base and measurement level. But, it would be a biased density model when some or whole part of anomalous bodies exist above the base level. We attempted to make a multiquadric surface of the survey area from topography with DEM (Digital Elevation Map) data. Then we constituted rectangular blocks which reflect real topography of the survey area by the multiquadric surface. Thus, we were able to carry out 3-D inversions which include information of topography. We named this technique, 3-D Gravity Terrain Inversion (3DGTI). The model test showed that the inversion model from 3DGTI made better results than conventional methods. Furthermore, the 3-dimensional model from the 3DGTI method could maintain topography and as a result, it showed more realistic geologic model. This method was also applied on real field data in Masan-Changwon area. Granitic intrusion is an important geologic characteristic in this area. This method showed more critical geological boundaries than other conventional methods. Therefore, we concluded that in the case of various rocks and rugged terrain, this new method will make better model than convention ones.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• 제27권3호
• /
• pp.393-400
• /
• 2009

Recently demand for the 3D modeling technology to reconstruct real world is getting increasing. However, existing geospatial data are mainly based on the 2D space. In addition, most of the geospatial data provide geometric information only. In consequence, there are limits in various applications to utilize information from those data and to reconstruct the real world in 3D space. Therefore, it is required to develop efficient 3D mapping methodology and data for- mat to establish geospatial database. Especially digital elevation model(DEM) is one of the essential geospatial data, however, DEM provides only spatially distributed 3D coordinates of the natural and artificial surfaces. Moreover, most of DEMs are generated without considering terrain properties such as surface roughness, terrain type, spatial resolution, feature and so on. This paper suggests adaptive and flexible geospatial data format that has possibility to include various information such as terrain characteristics, multiple resolutions, interpolation methods, break line information, model keypoints, and other physical property. The study area was categorized into mountainous area, gently rolling area, and flat area by taking the terrain characteristics into account with respect to terrain roughness. Different resolutions and interpolation methods were applied to each area. Finally, a 3D digital map derived from aerial photographs was integrated with the geospatial data and visualized.

• The Journal of the Korea Contents Association
• /
• 제5권6호
• /
• pp.248-254
• /
• 2005

Recently remote sensing technology is applied for construction planning and design areas by use of remote sensed satellite images according to engineering application technology in the various experimental tasks. In this study, it was applied for 3 dimensional terrain analysis and basic design by comparing with present railway and newly expanded double-tract railway route of forest sites on the new construction site of 15km at national railway lines, and then showed 3-D perspective images and fly simulation images to examine possibility of various application as terrain analysis modeling and running simulation at the corresponding course. As a result of its application, it gained the results not only improvement of present methods but also real various application possibilities.

• Journal of the Institute of Electronics Engineers of Korea SP
• /
• 제38권1호
• /
• pp.19-32
• /
• 2001

This paper proposes a local adaptive thresholding method based on a water flow model, in which an image surface is considered as a 3-dimensional (3-D) terrain. To extract characters from backgrounds, we pour water onto the terrain surface. Water flows down to the lower regions of the terrain and fills valleys. Then, the amount of filled water is thresholded, in which the proposed thresholding method is applied to gray level document images consisting of characters and backgrounds. The proposed method based on a water flow model shows the property of locally adaptive thresholding. Computer simulation with synthetic and real document images shows that the proposed method yields effective adaptive thresholding results for binarization of document images.

• Proceedings of the Korea Contents Association Conference
• /
• 한국콘텐츠학회 2005년도 춘계 종합학술대회 논문집
• /
• pp.131-137
• /
• 2005

Recently remote sensing technology is applied for construction projects planning and design areas by use of remote sensed satellite images according to engineering application technology in the various experimental tasks. In this study, It was applied for 3 dimensional terrain analysis and basic design by comparing to present railway and new expand doble-tract railway route of forest sites on the new construction site of 15km at national railway lines, and then showed 3-D perspective images and fly simulation images to possibility for various application as terrain analysis modeling and running simulation at the course. As a results of its applied, It gained the results not only improvement of present methods but also real various application possibilities.

• The Journal of the Korea Contents Association
• /
• 제6권5호
• /
• pp.42-55
• /
• 2006

In most multimedia systems, the environment is considered as a passive background. In virtual environment simulating real world, however, terrain affects many events such as wind, rain, cloud. Therefore, it is necessary to model terrain and meteorological phenomenon in order to simulate realistic virtual environment. In those modeling, not only height and location information but also environmental factors such as temperature and humidity are important. An event is composed of many activities and subevents based on causality and consists of precondition , procedure and effects. Each part of an event is formulated in terms of a number of parameter variables, which correspond to its associated factors on existence or states of entities and relation. This paper represents terrain and environmental factor using contour map. Moreover, we define various events and their procedures in terms of causality in virtual environment.

• Proceedings of the KSR Conference
• /
• 한국철도학회 2004년도 추계학술대회 논문집
• /
• pp.892-899
• /
• 2004

Recently remote sensing technology is applied for construction projects planning and design areas by use of remote sensed satellite images according to engineering application technology in the various experimental tasks. In this study, It was applied for 3 dimensional terrain analysis and basic design by comparing to present railway and new expand doble-tract railway route of forest sites on the new construction site of 15km at national railway lines,. and then showed 3-D perspective images and fly simulation images to possibility for various application as terrain analysis modeling and running simulation at the course. As a results of its applied, It gained the results not only improvement of present methods but also real various application possibilities.

• Korean Journal of Remote Sensing
• /
• 제9권2호
• /
• pp.21-34
• /
• 1993

Digitalized topographic information is necessary for many areas such as landscape analysis, civil engineering planning and design, and geographic information systems. It can also be used in flight simulator and automatic navigation of unmanned plane if it is stored in computer in relevant format. Topographic information is coded with various symbols including contour lines, and is analyzed by trained personnels. The information should be stored in computer for automatic analysis, but it requires a lot of time and manpower to enter the contours using manual input devices such as digitizing tablet. This paper deals with automatic extraction and reconstruction of 3D topographic information from 2D terrain map. Several algorithms were developed in this work including contour segment finding algorithm and contour segment linking algorithm. The algorithm were tested using real 2D terrain map.

• Geomechanics and Engineering
• /
• 제13권3호
• /
• pp.411-429
• /
• 2017

A Spectral Element Method for 3D seismic wave propagation simulation is derived based on the three-dimensional fluctuating elastic dynamic equation. Considering the 3D real terrain and the attenuation characteristics of the medium, the topographic effect of Wenchuan earthquake is simulated by using the Spectral Element Method (SEM) algorithm and the ASTER DEM model. Results show that the high PGA (peak ground acceleration) region was distributed along the peak and the slope side away from the epicenter in the epicenter area. The overall distribution direction of high PGA and high PGV (peak ground velocity) region is parallel to the direction of the seismogenic fault. In the epicenter of the earthquake, the ground motion is to some extent amplified under the influence of the terrain. The amplification effect of the terrain on PGA is complicated. It does not exactly lead to amplification of PGA at the ridge and the summit or attenuation of PGA in the valley.

• Journal of Institute of Control, Robotics and Systems
• /
• 제13권2호
• /
• pp.93-100
• /
• 2007

The mobile robots to rescue a life in a disaster area and to explore planets demand high mobility as well as recognition of the environment. To avoid unknown obstacles exactly in unknown environment, accurate sensing is required. This paper proposes a sensor fusion to recognize unknown obstacles accurately by using low-cost sensors. Ultrasonic sensors and infrared sensors are used in this paper to avoid obstacles. If only one of these sensors is used alone, it is not useful fer the mobile robots to complete their tasks in the real world since the surrounding environment in the real world is complex and composed of many kinds of materials. So infrared sensor may not recognize transparent or reflective obstacles and ultrasonic sensor may not recognize narrow obstacles, far example, columns of small diameter. Therefore, I selected six ultrasonic sensors and five infrared sensors to detect obstacles. Then, I fused ultrasonic sensors with infrared sensors in order that both advantages and disadvantages of each sensor are utilized together. In fusing sensors, fuzzy algorithm is used to cope with the uncertainties of each sensor. TAMRY which is terrain-adaptive mobile robot is used as the mobile robot for experiments.