• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.21 no.3
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• pp.277-287
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• 2003

As primary source data toward the systematic and efficient management of national land, the aerial photographs have been utilized in many different areas. However, the quality of aerial photographs does not meet the requirement of the users due to unidentified miscellaneous reasons. Aiming for the improvement of the quality of aerial photographs, we first investigated the current status of domestic rules and working procedures related to aerial photographing and film processing in great details. In addition, we investigated and analyzed those of advanced nations such as U.S.A., Canada, G.B. and so on. It was drawn from the comparison and analysis that the poor quality of domestic aerial photographs resulted from lack of the quantitative and objective standards on aerial photography specification as well as poor condition and aging problem of equipments such as aerial camera and film developing equipment. In this paper, we proposed a stepwise strategic plan which consists of the aerial photography specification and quantitative quality control standard taking into consideration the current status of domestic rules and working procedures.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.7 no.1
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• pp.131-139
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• 1987

In this study, characteristics of multi-photos and optimal photographing method are suggested by analyzing the normal case and convergent case with multiple method. The optimal photographing method is applied to deformation measurement of a model miniature structure under loading. Comparing with conventional measurement method in accuracy, efficiency and proprities of application of this method are suggested. As a result, the optimal photographing condition is ideal at $90^{\circ}$ convergent multiple case, whose measurement values approach to that of precision level within $5{\sim}9{\mu}m$ and bring more than about 55% improvement of accuracy comparing with normal case at the number of photos respectively. Therefore application of this method in deformation measurement as well as precision analysis of structures is desired in precision and economical aspect.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.8 no.2
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• pp.23-29
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• 1990

Non-metric camera is more profitable than metric camera for geometric analysis of small and elaborate structures, because focal length control of non-metric camera is flexible while generally metric camera has limited focal length. And if the problem of conventional method requiring much time and endeavor to measure three dimensional positions of control points will be solved effectively, it is possible to analyze very close-range photogrammetry more easily and quickly. The purposes of this study are to propose the efficiency of non-metric camera and to reduce difficulty of control survey sharply by introducing self-control survey method. For these, very close-range photographs of the small object were obtained by using non-metric camera calibrated for systematic errors and then bundle adjustment is used for analysis procedure. As a result, the superiority of non-metric camera in analyzing very close-range photographs and the application proptriety of self-control survey were proved, therefore it is expected to be able to apply to precise analysis of small structures or spearhead parts.

• The korean journal of orthodontics
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• v.38 no.4
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• pp.265-274
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• 2008

Objective: The aim of this study was to evaluate the potency of panoramic radiography for the detection of maxillary impacted canines. Methods: Twenty-five patients were selected, comprised of 7 males (mean age: 10.9 years, range: 8.5 - 14.5 years) and 18 females (mean age: 10.9 years, range: 8.2 - 15.7 years). In total, thirty-five maxillary impacted canines were estimated. The position of the canine and root resorption of adjacent teeth were evaluated on panoramic radiography and 3D CT. Results: Except for angulation to the occlusal plane, the other parameters, such as tooth length, crown width, vertical distance and lateral shift showed larger values on panoramic radiography compared to 3D CT. In palatally impacted cases, the angulation of canine was smaller, and the vertical distance to the occlusal place was larger on panoramic radiography than 3D CT. For labially impacted canines, tooth length, crown width, and angulation to the occlusal plane were similar for the two methods. The sensitivity for detecting root resorption on panoramic radiography was calculated as being 33.3% of 3D CT. Conclusions: The position of labially impacted canines can be effectively estimated using panoramic radiography, but palatally impacted canines need further investigation such as 3D CT for proper diagnosis.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.383-383
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• 2015

하천의 하상고 측량은 하상변동 분석, 서식처 구조 등을 이해하는데 매우 중요한 정보를 제공한다. 하지만, 현재까지 대부분의 하상고 측량은 일정한 간격의 하천 단면 측량에 의해서 행해져 왔다. 최근 GPS와 다중 빔 측심기를 이용하여 하상의 3차원적 형상을 조밀하게 측량하고 있으나 비용이 많이 들기 때문에 긴 하천 구간을 전부 측량하지는 못하고 특정한 부분에 대해서만 집중하고 있다. 항공 LiDAR의 경우 넓은 지역에 대해 신속하고 고해상도로 지형을 측량할 수 있으나 수중 투과 장비가 고가이며, 일반 적색 레이져 기반 LiDAR는 수중을 측정하지 못하여 하상 측량에 한계가 있다. 이에 대한 대안으로 활용할 수 있는 방법은 광학 기반의 원격 탐사에 의한 수심 측량 방법이다. 이 방법은 얕은 수심의 하천에 대한 활용되었는데, 광학 센서 이미지나 항공사진 등을 이용한다. 본 연구에서는 저고도에서 촬영한 고해상도 디지털 항공사진을 이용하여 모래하천의 수심을 추정하였다. 이 방법은 항공사진의 적색 및 녹색 색상값과 현장에서 정밀한 측위 하에 측량한 수심값 사이의 관계를 이용한다. 이를 통해 보정식을 수립하고 검사 자료를 이용하여 검증한 후 항공사진의 해당 지역에 대해 수심 부분을 마스킹 처리하여 하상고를 구축하였다. 검사 자료에 대한 RMSE는 약 12 cm로 나타났다. 이를 활용하여 대상 구간의 3차원적 지형 형상을 구축하였다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.19 no.1
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• pp.77-83
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• 2001

To product the map by terrestrial photogrammetry method, a few rather nuisance stereo image acquiring processing and plot using expensive analytical instruments have to be performed. In this study, plot was made by acquiring and rectification image using simple method rather than above it. For this, geometry rectification system was constructed for the generation of single ortho-image analysis. and these ortho-images of architecture were made and analysed by appling various warping methods. As a result, the performance of single image analysis could be estimated, and it is expected that the application of this is possible to various non-topographic photogrammetry.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.23 no.4
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• pp.401-408
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• 2005

Presently many constructions establish in underwater, but approaching to underwater constructions are difficult, for comparing with ground, underwater environment is different in media. Usually measurement methods for underwater constructions are using tapes, using depth gauges, using acoustic positioning systems. But, tapes are hard to measure the correct distance, for applying a right tension is not easy in underwater. Depth gauges have a weakness in settling, for it takes long time to do it. Acoustic positioning systems don't work well in confined spaces and cost a lot. Hence, the purpose of this study is, at first, to understand rays path in multimedia like water, glass and air. The second thing is to perform a camera calibration at the field to compare with the interior orientation parameter. And the third thing is to find out whether photogrammetry is applied for underwater object in using cube for accuracy examination. The last thing is to perform underwater photogrammetry about underwater object, which is pier model and riverbed. We came to the conclusion through this experiment that the applying underwater photogrammerty for underwater constructions and underwater ground is possible.

• Tunnel and Underground Space
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• v.19 no.1
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• pp.31-42
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• 2009

One set of hardware system of guide point method (GP method), modified from the multistage convergent photographing technique, was developed to interpret the geometrical characteristics of Joints photogrammetrically on rock slope. Before the field application of the hardware system, the level of errors and constraints that ran be acceptable in the field measurement has been severely investigated in the laboratory and the optimum photographing scheme was analyzed. The range of the most suitable convergence angle between two cameras was $25^{\circ}{\sim}150^{\circ}$ and the photographing distance was about 5.5 m when using a 2 M pixel digital camera. An extended analyzing technique, which was newly developed in this study, was applied to the field measurement to magnify the benefits of GP method. This technique can be applied when survey for the wide range of rock surface is necessary. The global coordinates of ground control points for the neighbor photographing area ran be introduced without any preparation from the previous photographed area using this technique. It could reduce phographing time in the field.

• Aerospace Engineering and Technology
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• v.3 no.1
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• pp.126-133
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• 2004

Photogrammetry, as its name implies, is a 3-dimensional coordinate measuring technique that uses photographs as the fundamental medium for metrology. In the last few years the accuracy of photogrammetry has increased dramatically thanks to the rapid advance of digital camera manufacturing technique. This paper discusses photogrammetric measurement of the interface surface of MSC(Multi-Spectral Camera), which is a main payload of KOMPSAT-2. Total 24 paper targets on the objective surfaces and two scale bars calibrated with high accuracy were used for measurement, and multiple images were taken from 11 different camera angles by using a spacecraft rotation dolly. As a result of analysis, 3D coordinates of each targeted point were obtained and the flatness value based on the selected reference plane was calculated and compared with the pre-determined requirement. The technique acquired by this study is expected to be used for the 3D precise measurement of ultra-light weight and inflatable space structures such as a satellite antenna and a solar array.

• The Journal of the Korea Contents Association
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• v.9 no.4
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• pp.189-197
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• 2009

A digital image usually has 8 bits of depth basically representing pixel intensity ranging for [0 255]. These pixel range allow 256 step levels of pixel values in the image. Thus the greyscale value for a given image is an integer. When we carry out interpolation of a given image for resizing we have to round the interpolated value to integer which can result in loss of quality on perceived color values. This paper proposes a new method for recovering this loss of information during interpolation process. By using the proposed method the pixels tend to regain more original values which yields better looking images on resizing.