사진측정법을 이용한 해빈단면의 추정

김백운,박용안,오임상,김부근,최경식,Kim, Baeck-Oon,Park, Yong-Ahn,Oh, Im-Sang,Khim, Boo-Keun,Choi, Kyung-Sik 한국해양학회 1998 바다 Vol.3 No.4

본 연구는 비측량용 사진기를 이용한 근거리 사진측정법을 적용하여 해빈단면을 추정하는 방법을 제시한다. 수평면 위에 고정된 비디오로부터 획득한 경사비디오영상을 해석하는 방법을 기초로 다음 두 가지 관점을 고려하여 경사사진 해석에 적합한 방정식을 유도하였다. (1) 사진기가 광축에 대하여 회전되는 것을 허용하였다. (2) 정확도를 향상시키기 위하여 렌즈왜곡을 비롯한 사진 계통상의 오차를 보정하는 단순한 오차모형을 도입하였다. 수정된 방정식을 검증하기 위하여 1998년 2월에 동해시 해빈에서 사진촬영과 정밀한 수준측량을 수행하였다. 그 결과 근거리 사진측정을 통한 해빈단면 추정값과 실제 측량값 사이의 수직거리에 대한 RMS 오차는 10 cm 이내였다. This study presents a close-range photogrammetry that is applicable to beach profile estimation using a non-metric camera. Based on the analysis of oblique video image in which the video camera was installed on a horizontal plane and the field of view was fixed, a new equation to analyze a photograph was developed considering the following aspects: (1) camera is allowed to be rotated about its optical axis and (2) a simple error model is adopted to correct lens distortion and other systematic errors associated with the non-metric camera, which improves accuracy of non-metric imageries. To test the modified technique, photographs of the beach were taken near the Donghae City in February, 1998. In addition, beach profiles were surveyed with conventional dumpy level and surveying staff. RMS error between the estimated and measured beach profiles is less than 10 cm in elevation.

동해안 군사시설보호구역 주변 향호 연안역을 대상으로 무인항공사진측량에 관한 예비 연구

김백운,윤공현,장태수,박장준,김성필 한국해양과학기술원 2017 Ocean and Polar Research Vol.39 No.2

To evaluate the accuracy of UAV photogrammetry for Hyangho coast, eastern coast of Korea, we conducted a field experiment wherein UAV photogrammetry test was repeated three times. Since the Haygho coast is located within a military reservation zone, it was necessary to obtain permission to gain access to the beach and to have sensitive aerial photographs showing military facilities inspected and cropped. The standard deviation of the UAV shooting position between the three tests was less than 1 m, but repeatability of footprint on the ground was low due to wind-driven variability of the UAV pose. Selfcalibrating bundle adjustment(SCBA) of implementing non-metric camera calibration was failed in one test. In two tests, the vertical error was twice as large as the pixel size except for those areas that were subject to security inspection and cropping. Given the problems that can arise with regard to the repeatability of the shooting area as well as the possibility of failure with regard to SCBA, we strongly recommend that UAV photogrammetry in coastal areas needs to be repeated at least twice.

서해 배타적경제수역(EEZ)내 해사채취구역의 지형변화

김백운,이상호,양재삼 한국지구과학회 2005 한국지구과학회지 Vol.26 No.8

Two data sets of repeated hydrographic surveys with a single beam echo-sounder were obtained to investigate morphological changes on a sand mining site within EEZ near the Eocheong Islands, West Sea of Korea. Their accuracies of depth measurement, estimated from the crossover analysis, correspond to the Oder 2 of IHO standards. Bathymetric maps show a feature of 300 m wide and 10 m deep hollow, whose evolution can be seen in difference grids of the two bathymetric maps. However, data of higher accuracy and resolution enable precise quantification of extracted sand volume. Since this morphological change could affect sedimentary environment as well as benthic ecology, environmental impact assessment based on scientific research data is required for management and sustainable development of limited sand resource. 서해배타적경제수역내해사채취구역에서해저지형변화를규명하기위하여 2회에걸쳐단일빔음향측심기를이용한측심자료를획득하였다. 교차점분석에의한측심자료의정확도는 IHO 표준의 2등급에해당하였다. 지형도는폭300 m, 깊이 10 m 의구덩이형태를나타내었으며, 이러한지형의변화과정이두지형도수심차의분포에서표현되었 다. 그러나해사채취량을정량화하기위해서는더욱정확하고정밀한자료가요구된다. 이러한지형변화는퇴적환경및저서생태환경에영향을미칠수있으므로한정된모래자원을관리하고지속가능한개발을위해서는과학적인조사자료에근거한환경영향평가가요구된다.

Image Processing for Video Images of buoy motion

김백운,조홍연 한국해양과학기술원 2005 Ocean science journal Vol.40 No.4

In this paper, image processing technique that reduces video images of buoy motion to yield time series of image coordinates of buoy objects will be investigated. The buoy motion images are noisy due to time-varying brightness as well as non-uniform background illumination. The occurrence of boats, wakes, and wind-induced white caps interferes significantly in recognition of buoy objects. Thus, semi-automated procedures consisting of object recognition and image measurement aspects will be conducted. These offer more satisfactory results than a manual process. Spectral analysis shows that the image coordinates of buoy objects represent wave motion well, indicating its usefulness in the analysis of wave characteristics.

낙동강 하구 해안선변화 연구를 위한 모자이크 항공사진의 구축

김백운,김부근,이상룡 한국해양과학기술원 2005 Ocean and Polar Research Vol.27 No.4

This paper presents a method for obtaining mosaic aerial photographs that are useful for a long-term shoreline change study in the Nakdong estuary. Although this method involves digital photogrammetry software off the shelf, its usage can be simplified to accomodate the shoreline change study. Ground control points, which are common in aerial photographs, were measured from digital maps. Block triangulation was highly affected by land-based GCPs. Extension of tie points near the shoreline to vertical control points gave more reliable results for the block triangulation. A constant Digital Elevation Model (DEM), close to mean sea level, was employed to produce ortho-rectified photographs, from which mosaic photographs were made. Accuracy of photographs were found to be acceptable for the analysis of long-term shoreline change, and the promising construction of a shoreline change database in the Nakdong estuary.

낙동강 하구 신자도 해빈 퇴적물의 시·공간적인 변화

김백운,김부근,이상룡 한국해양환경·에너지학회 2012 한국해양환경공학회 학술대회논문집 Vol.2012 No.5

낙동강 하구 신자도 해빈 퇴적물의 시·공간적인 변화

김백운,김부근,이상룡 대한조선학회 2012 대한조선학회 학술대회자료집 Vol.2012 No.5

The Use of Elevation Adjusted Ground Control Points for Aerial Triangulation in Coastal Areas

김백운,윤공현,이창경 대한토목학회 2014 KSCE JOURNAL OF CIVIL ENGINEERING Vol.18 No.6

A method to improve the quality of aerial triangulation for photographs in coastal areas is proposed. Uneven distribution of groundcontrol points and tie points due to the presence of sea water causes the aerial triangulation to produce a systematic error, which isrepresented by elevation difference of ground control points between stereo model surface and real topography. Compensation of theelevation difference is given to the ground control points with which the following triangulation corrects exterior orientationparameters so as to match stereo model surface to real topography. An experimental study using historical photographs for beachenvironment, GPS surveys of ground control points and independent check points demonstrates that the proposed method givesRMSE of the elevation difference less than 0.1 m.

항공사진을 이용한 방포항 인근 해빈의 장기간 해안선 변화 분석

김백운 ( Baeck Oon Kim ),윤공현 ( Kong Hyun Yun ),이창경 ( Chang Kyung Lee ) 대한원격탐사학회 2013 大韓遠隔探査學會誌 Vol.29 No.5

장기간 해안선 변화 자료의 구축을 통해 해안선의 시·공간적인 변화 양상을 분석하고, 이에 근거하여 해안침식의 향후 경향을 파악하는 일은 연안관리에 매우 중요한 역할을 한다. 본 연구에서는 수치항공사진을 이용하여 방포항 인근 해안지역의 장기간(1985년 ~ 2009년) 해안선 변화 탐지를 위해 항공삼각측량, 지상기준점측량, 수치도화, 그리고 해안선 변화율을 산정하였다. 그 결과 방포해빈과 꽃지해빈의 해안선은 각각 0.2 m/yr와 최대 0.8 m/yr로 침식된 것으로 파악되었다. 또한 등고선 변화 통하여 꽃지 해빈의 북부지역에서 침식현상이 가장 뚜렷하게 나타났으며 표고 1 m 간격의 등고선은 최대 45 m 후퇴하였음을 알수 있었다. 이러한 변화는 다양하고 복합적인 요인에 의해 발생할 수 있으며 주된 요인은 1990년대 말에 설치된 해변 옹벽이 해안침식을 일으키는 주요 원인으로서 추정되고 있다. To analyze tendency of temporal and spatial change of shorelines and to estimate rate of shoreline changes using long-term shoreline change data is very important for the coastal environmental management. In this study, investigation was conducted to estimate the rate of shoreline changes using long-term shoreline change data from the year 1985 to 2009 aerial photographs. In this process aerial triangulation, GPS surveying and digital mapping was done for the estimation of changes. As the results, shorelines of Bangpo and Kkotji Beach retreated at a maximum rate of 0.2 m/yr and 0.8 m/yr, respectively. The shoreline could be changed by various factors. However, it was presumed that coastal erosion has been mainly affected by retaining wall constructed in the late 1990s.

낙동강 하구역 울타리 섬의 해안선 변화율

김백운(Kim, Baeck-Oon),김부근(Khim, Boo-Keun),이상룡(Lee, Sang-Ryong) 한국해안해양공학회 2007 한국해안해양공학회 논문집 Vol.19 No.4

본 연구는 항공사진을 이용하여 낙동강 하구 울타리 섬의 장기간의 지형 변화를 제시한다. 수치사진측량을 이용하여 모자이크 항공사진을 구축하고 이로부터 1975년부터 2001년까지 6회의 해안선 자료를 산출한다. GIS에 근거한 수치해안선분석시스템을 이용하여 EPR(End Point Rate), JKR(Jackknife Rate) 및 LRR(Linear Regression Rate)와 같은 3 종류의 해안선 변화율을 산정한다. 신자도와 도요등에서 매우 현격한 변화가 나타났다. 신자도의 서쪽 부분은 바다 쪽으로 전진한 반면 동쪽 부분은 육지 쪽으로 후퇴하였으며, 이 결과 섬이 반시계 방향으로 회전한 것처럼 보인다. 양쪽 끝 부분에서 해안선 변화율은 20 m/yr에 달한다. 도요등은 1993년에 백합등 전면에 새롭게 출현하였으며 40 m/yr의 해안선 변화율로 전진하였다. 해안선 변화율은 울타리 섬 내에서뿐만 아니라 울타리 섬 간에도 차이가 있으며, 동쪽으로 가면서 증가하는 경향을 보인다. 이러한 해안선 변화율의 공간적인 변동성을 이해하기 위해서는 연안개발이 수리역학과 퇴적작용에 미치는 영향을 상세히 조사할 필요가 있다. This study presents long-term shoreline changes of barrier islands in Nakdong Estuary using aerial photographs. Digital photogrammetry is used for constructing mosaic aerial photographs, which yield six sets of shoreline data ranging from 1975 to 2001. Three kinds of rate of shoreline changes such as EPR (End Point Rate), JKR(Jackknife Rate) and LRR (Linear Regression Rate) are computed by a GIS-based Digital Shoreline Analysis Systems. There have been remarkable changes both in Sinja Island and Doyodeung. Western part of Sinja Island advanced seaward, whereas eastern part retreated landward, giving appearance that the island rotated counterclockwise. Rate of shoreline changes at both ends reach 20 m/yr. Doyodeung occurred newly in front of Baekhapdeung in 1993, resulting in shoreline advance in a rate of 40 m/yr. Rate of shoreline changes differ both within and between barrier islands and have a tendency to increase eastward. To understand this spatial variability of rate of shoreline changes, it is suggested to make a detailed investigation into the impact of coastal development on hydrodynamic and sedimentary processes.