• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.15 no.1
• /
• pp.66-76
• /
• 2016

Determination of type of a vehicle is being used in various areas such as collecting tolls, collecting statistical traffic data and traffic prognosis. Because most of the vehicle type classification systems depend on vehicle length indirectly or directly, highly reliable automatic vehicle length measurement system is crucial for them. This study makes use of a pencil beam laser rangemeter and devises a mechanical device which rotates the laser rangemeter. The implemented system measures the range between a point and the laser rangemeter then indicates it as a spherical coordinate. We obtain several silhouettes of cross section of the vehicle, the rate of change of the silhouettes, signs of the rates then squares the rates to apply cell averaging constant false alarm rate (CA-CFAR) technique to find out where the border is between the vehicle and the background. Using the border and trigonometry, we calculated the length of the vehicle and confirmed that the calculated vehicle length is about 94% of actual length.

• Journal of Navigation and Port Research
• /
• v.26 no.4
• /
• pp.473-479
• /
• 2002

The estimation of the volume of a pit excavation is often required in many surveying, soil mechanics, highway applications and transportation engineering situations. The calculation of earthwork plays a major role in plan or design of many civil engineering projects such as seashore reclamation, and thus it has become very important to improve the accuracy of earthwork calculation. In this paper the spot height method, proposed formulas(A, B, C), and chen and Line method are compared with the volumes of the pits in these examples. And we proposed an algorithm of finding a terrain surface with the free boundary conditions and both direction spline method drawback, i.e., the modeling curves form peak points at the joints. To avoid this drawback, the cubic spline polynomial was chosen as the methematical model of the new method. From the characteristics of the cubic spline polynomial, the modeling curve of the new method was smooth and matched the ground profile well. As a result of this study, algorithm of proposed three methods to estimate pit excavation volume provided a better accuracy than spot height, chamber, chen and Lin method. And the mathematical model mentioned makes is thought to give a maximum acccuracy in estimating the volume of a pit excavation.

• Korean Journal of Remote Sensing
• /
• v.16 no.3
• /
• pp.221-233
• /
• 2000

An intertidal topography is continuously changed due to morphodynamics processes. Detection and measurement of topographic change for a tidal flat is important to make an integrated coastal area management plan as well as to carry out sedimentologic study. The objective of this study is to generate intertidal DEM using leveling data and waterlines extracted from optical and microwave remotely sensed data in a relatively short period. Waterline is defined as the border line between exposed tidal flat and water body. The contour of the terrain height in tidal flat is equivalent to the waterline. One can utilize satellite images to generate intertidal DEM over large areas. Extraction of the waterline in a SAR image is a difficult task to perform partly because of the presence of speckle and partly because of similarity between the signal returned from the sea surface and that from the exposed tidal flat surface or land. Waterlines in SAR intensity and coherence map can effectively be extracted with MSP-RoA edge detector. From multiple images obtained over a range of tide elevation, it is possible to build up a set of heighted waterline within intertidal zone, and then a gridded DEM can be interpolated. We have tested the proposed method over the Gomso Bay, and succeeded in generating intertidal DEM with relatively high accuracy.

• Journal of Korean Society for Geospatial Information Science
• /
• v.13 no.2 s.32
• /
• pp.29-37
• /
• 2005

The compensation data for submerged land have been filed in the form of document or managed with spread sheet like Excell up to now. In the case of dam or highway construction, huge compensation data for the submerged or included land have been managed inefficiently by the administrative manpower. Moreover, where and how to keep the enormous data becomes big problems. In response to the requirements, an submerged land compensation management system based on the location and property information of parcels was developed. The compensation management system has many functions including site searching for compensation, compensation money computing, and compensation data managing. It is expected that the submerged land compensation management system creates various information effects.

• Journal of Korean Society for Geospatial Information Science
• /
• v.12 no.4 s.31
• /
• pp.61-68
• /
• 2004

In this paper, we suggest an automatic technique to obtain 3-D road information in complex urban areas using road pavement markings. This method is composed of following three main steps. The first step is extracting the pavement markings from aerial images, the second one is matching the same pavement markings in two aerial images, and the last one is obtaining the 3-D coordinates of those using EOP(exterior orientation parameters) of aerial images. Here, we focus on the first and second step because the last step can be performed by using the well hewn collinearity condition equation. We used geometric properties and spatial relationships of the pavement markings to extract the lane line markings on the images and extracted arrow lane markings additionally using template matching. And then, we obtained 3-D coordinates of the road using relational matching for the pavement markings. In order to evaluate the accuracy of extraction, we did a visual inspection and compared the result of this technique with those measured by digital photogrammetric system.

• Journal of Korean Society for Geospatial Information Science
• /
• v.5 no.1 s.9
• /
• pp.71-80
• /
• 1997

This paper suggests a Map Accuracy Standards by analyzing U.S. National Map Accuracy Standards, by considering korean terrain feature and statistical error theory for paper and digital maps on the scale of 1:50,000. Map accuracy standards require horizontal accuracy to be reported as a circular error with 90% confidence level through Linear Error Probable(LEP) theory and Circular Error Probable(CEP) theory. In order to verify the proposed methodology for positioning accuracy testing, several kinds of test point were selected and tested. These test points were extracted at the centers of roads and bridges, the comers of the independent building, the edges of geographical botany, and the tops of mountains. The positioning accuracy assessment was peformed by comparing the positions of test points in digital maps generated three different sources with those acquired by high accurate GPS surveying. The digital maps were produced from aerial photographs and SPOT satellite image using analytical plotter and 1:50,000 paper map.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2012.05a
• /
• pp.587-587
• /
• 2012

현재 대부분 하천관리의 흐름해석에서 주가 되었던 1차원 분석은 하천 단면에 따른 횡적인 수면차, 유속분포를 분석할 수 없다는 단점을 가지고 있으며, 특히 유량 및 유속이 급속도로 늘어나는 홍수시에는 그 오차가 더욱 커질 수 있다. 반면에 2차원 모형의 흐름해석은 사행하천의 흐름 특성과 만곡부에서의 종 횡방향 수면경사 및 양안의 수면차와 합류지점의 횡방향 흐름 등의 영향을 고려할 수 있으며 1차원 해석과는 달리 전 단면에 걸쳐 유속 및 수위 분포를 나타낼 수 있어 실제흐름에 가까운 수리량을 얻을 수 있다. 본 연구를 위해 적용된 해석모형인 SMS는 미국 Brigham Young 대학의 환경모형연구실과 미공병단(USACE)의 수로실험국(WES) 등에서 개발한 프로그램으로서 RMA2, RMA4, SED2D 모형 등으로 구성되어 있다. 각각의 모형은 수리 동역학적 해석, 오염물 이송확산 해석, 유사의 이송 및 퇴적 해석이 가능하며 이 중 RMA2를 이용한 2차원 흐름해석을 통하여 보다 적합한 하천관리에 이용가능하도록 하고자 한다. 연구대상 지역은 제주도 한천 하류부로서 제주도 하천 특성상 평상시 건천의 상태를 이루고 있으나 태풍 및 집중호우시 홍수유출이 발생하여 수위가 급격하게 상승하는 양상을 보인다. 대표적인 예로 태풍 '나리'시 최대 일강우량 420mm로 인한 인근 지역에 0.5 ~ 1.5m의 침수흔적을 보이고 있다. 본 연구에서는 2011년 최고수위를 기록한 태풍 '무이파'를 대상으로 하였으며 대상지역의 Kalesto를 이용한 수위-유속 자료를 이용하여 산출된 유량을 경계조건으로 사용하였고 격자망 형성을 위한 지형 데이터는 지형도 및 측량자료를 이용하여 구축하였다. 사용된 대표적인 매개변수는 하상의 조도계수를 나타내는 Manning의 n값과 유체의 밀도, 속도구배, 구조 등 여러 가지의 유체조건에 따라 변하는 성질인 와점성계수(eddy viscosity)로 요약할 수 있으며 Manning의 n값은 하천설계기준에 따른 하천기본계획의 조도계수를 사용하였고 와점성계수는 적합한 흐름 분포를 결정하기 위해 흐름이 안정될 때까지 변화시켜 해석을 시행하였다. 해석결과 만곡부에서는 급한 흐름을 보이고 있으며 최대하폭 구간에서는 완만한 흐름이 나타나 사행하천의 흐름특성과 횡적인 하천단면에 따른 변화, 하상고 차이로 인한 유속분포를 확인할 수 있으며 이는 보다 유용한 하천관리에 이용가능할 것으로 사료된다.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.9
• /
• pp.4192-4198
• /
• 2011

Terrestrial LiDAR is a high precision positioning technique to monitor the behavior and change of structures and natural slopes, but it has depended on subjective hand intensive tasks for the classification(surface and vegetation or structure and vegetation) of positioning data. Thus it has a couple of problems including lower reliability of data classification and longer operation hours due to the surface characteristics of various geographical and natural features. In order to solve those problems, the investigator developed a technique of using the NDVI, which is a major index to monitor the changes on the surface(including vegetation), to categorize land covers, combining the results with the terrestrial LiDAR data, and classifying the results according to items. The application results of the developed technique show that the accuracy of convergence was 94% even though there was a problem with partial misclassification of 0.003% along the boundaries between items. The technique took less time for data processing than the old hand intensive task and improved in accuracy, thus increasing its utilization across a range of fields.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.26 no.3D
• /
• pp.535-540
• /
• 2006

This paper presented an effective strategy to extract the buildings and to reconstruct 3-D buildings using high-resolution multispectral stereo satellite images. Proposed scheme contained three major steps: building enhancement and segmentation using both BDT (Background Discriminant Transformation) and ISODATA algorithm, conjugate building identification using the object matching with Hausdorff distance and color indexing, and 3-D building reconstruction using photogrammetric techniques. IKONOS multispectral stereo images were used to evaluate the scheme. As a result, the BDT technique was verified as an effective tool for enhancing building areas since BDT suppressed the dominance of background to enhance the building as a non-background. In building recognition, color information itself was not enough to identify the conjugate building pairs since most buildings are composed of similar materials such as concrete. When both Hausdorff distance for edge information and color indexing for color information were combined, most segmented buildings in the stereo images were correctly identified. Finally, 3-D building models were successfully generated using the space intersection by the forward RFM (Rational Function Model).

• Proceedings of the Korea Water Resources Association Conference
• /
• 2022.05a
• /
• pp.113-113
• /
• 2022

기후 변화에 따른 집중호우의 증가로 유례없는 홍수가 발생하기도 한다. 홍수 대비를 위한 수리구조물 설계 및 홍수 예측을 위해서는 기초자료인 유량 자료가 중요하며, 이는 Rating-curve를이용하여 산정하는 것이 일반적이다. 하지만, 이를 기왕의 데이터가 부족한 지역과 적용수위 이상에 대해 적용하는 것에 한계가 있다. 2020년 8월 섬진강에 발생한 홍수는 홍수량의 추정이 어려울 뿐 아니라 기존의 Rating curve를 활용하여 홍수량을 추정하는데 한계가 있다. 섬진강 하천정비기본계획(2021)에 따르면 섬진강 남원(신덕리) 관측소는 100년 빈도 홍수량이 7,470m³/s인 반면, 선형 보간을 통한 Rating curve 외삽 결과 약 23,000m³/s로 많은 차이 나는 것을 확인할 수 있다. 따라서, 본 연구에서는 외삽의 불확실성과 직접 측량에 어려움이 있는 홍수기 유량 추정을 위해 수리학적 해석 방법을 이용한 간접유량 산정기법을 제시하였다. 수치해석모형을 이용하여 홍수사상을 재현하고, 이를 역으로 이용하여 관측 수위와 근접한 계산 결과를 보인 입력 자료로부터 대상 지역의 유량을 간접적으로 산정하였다. 상류단 유량자료의 생성을 위하여 Rating curve의 변수에 대하여 무작위 조합을 생성하였고, K-River(1차원 수리해석 모형)를 이용하여 MCS(Monte Carlo Simulation)를 수행하였다. 계산된 수위와 관측 수위간 수위 재현성 평가(NSE, RSR)를 통해 최적 결과를 나타낸 Rating Curve의 변수들로부터 경계조건의 Rating Curve를 산정하였다. 방법론의 검증을 위해 요천 합류부에 적용하였으며, 그 결과 기존 곡선식의 외삽에 따른 유량 자료의 수위 재현성과 비교하여 개선된 것을 확인하였다. 이를 활용하여 수자원 유량 자료의 신뢰도 개선에 활용이 가능할 것으로 판단된다.