• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.5
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• pp.585-597
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• 2009

This research aims to develop a registration method to remove the geometric inconsistency between aerial images and LIDAR data acquired from an airborne multi-sensor system. The proposed method mainly includes registration primitives extraction, correspondence establishment, and EOP(Exterior Orientation Parameters) adjustment. As the registration primitives, we extracts planar patches and intersection edges from the LIDAR data and object points and linking edges from the aerial images. The extracted primitives are then categorized into horizontal and vertical ones; and their correspondences are established. These correspondent pairs are incorporated as stochastic constraints into the bundle block adjustment, which finally precisely adjusts the exterior orientation parameters of the images. According to the experimental results from the application of the proposed method to real data, we found that the attitude parameters of EOPs were meaningfully adjusted and the geometric inconsistency of the primitives used for the adjustment is reduced from 2 m to 2 cm before and after the registration. Hence, the results of this research can contribute to data fusion for the high quality 3D spatial information.

• The Journal of the Korea Contents Association
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• v.14 no.5
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• pp.425-435
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• 2014

The research for extracting man-made features such as building and road from the aerial photograph or satellite imagery has been performed actively. As lately the resolution of digital aerial photographs was improved, unwanted features(noise) would be often detected. An edge detection algorithm is developed to make up for such a noise problem, make boundaries of wanted objects clear and extract only needed features. The algorithm developed in this research performs separating RGB channels, differencing between channels, transforming in to binary images, excluding noises and restoring shapes, and edge extraction in order. The images to be used for edge detection are prepared through bundle adjustment, DTM extraction, orthorectification and mosaicking. The roof edges of small building on preprocessed digital aerial orthophotos were extracted using the algorithm developed in this study. The validity of the algorithms was proved by comparing edge results of small building extracted in this study with those of conventional methods.

• Korean Journal of Remote Sensing
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• v.26 no.5
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• pp.593-603
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• 2010

Most spatial data acquisition systems employing a set of frame cameras may have suffered from their small fields of view and poor base-distance ratio. These limitations can be significantly reduced by employing an omni-directional camera that is capable of acquiring images in every direction. Bundle Block Adjustment (BBA) is one of the existing georeferencing methods to determine the exterior orientation parameters of two or more images. In this study, by extending the concept of the traditional BBA method, we attempt to develop a mathematical model of BBA for omni-directional images. The proposed mathematical model includes three main parts; observation equations based on the collinearity equations newly derived for omni-directional images, stochastic constraints imposed from GPS/INS data and GCPs. We also report the experimental results from the application of our proposed BBA to the real data obtained mainly in urban areas. With the different combinations of the constraints, we applied four different types of mathematical models. With the type where only GCPs are used as the constraints, the proposed BBA can provide the most accurate results, ${\pm}5cm$ of RMSE in the estimated ground point coordinates. In future, we plan to perform more sophisticated lens calibration for the omni-directional camera to improve the georeferencing accuracy of omni-directional images. These georeferenced omni-directional images can be effectively utilized for city modelling, particularly autonomous texture mapping for realistic street view.

• International Journal of Highway Engineering
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• v.8 no.1 s.27
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• pp.65-75
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• 2006

According to development of computer technology, the utilization of the fourth generation of digital photogrammetry progresses favorable. Especially the method of using digital video camera is very practicable and has an advantage such as a profitability for the amateur. In road field which if centrical facilities of national industry, this method was utilized to acquire road information for the safety diagnosis or maintenance. In this study, 3-dimensional position information of road centerline was extracted using digital video camera which has practicality and economical efficiency. This data could be a basic source in road information project.

• Korean Journal of Optics and Photonics
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• v.31 no.4
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• pp.176-182
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• 2020

The possibility of replacing the condensing-prism film used in conventional backlight units with a light-guide plate engraved with a submicrometer-periodic diffraction grating was investigated. The optimal period for the diffraction grating was determined through simulation and experiment, and the transmission-mode efficiency of the diffraction grating was calculated in terms of the polar angle and azimuthal angle of the incident light. In addition, the effects of the two methods of optimizing the polar angle and the directional angle were compared by simulation, by suggesting the shape and configuration of the light-guide plate, so that more light could be extracted by diffraction. By using a ray-tracing program, the luminance angular distribution of the light-guide plate engraved with the diffraction grating was calculated and compared to the luminance angular distribution for each actual prototype.

• Journal of Korean Society for Geospatial Information Science
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• v.14 no.4 s.38
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• pp.61-70
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• 2006

This paper presents photogrammetric processing to generate digital elevation models using SPOT-5 HRG stereo images and deals with the accuracy potential of HRG (High Resolution Geometry) supermode imagery for DEM generation. After bundle adjustment was preformed for sensor modelling, digital surface models were generated through the procedures of Epipolar image resampling and image matching. The DEM extracted from HRG imagery was compared along several test sections with the the refernce DEM which was obtained from the digital topographic maps of a scale of 1 to 5000. The ratio of the zone with DEM errors less than 5m to the whole zone was 53.8%, and about 2.5m RMSE was showed when assuming that the zones larger than 5m were affected by clouds, water bodies and buildings and excluding those zones from accuracy evaluation. In addition, the three-dimensional bird's eye view model and 3D building model were producted based on the DSM which was extracted from SPOT-5 HRG data.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.8
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• pp.706-712
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• 2013

In this paper, channel modeling of VLC(Visible Light Communication) was investigated under indirect lightning circumstance which was the way that all phontons started from LED(Light Emitting Diode) were reached on the floor with NLOS paths. I supposed width(6m), depth(4m), height(2.2m) cube room circumstance for VLC communication channel and supposed that 4 LEDs were located at 2m height, which emitted photons at the direction of wall and ceiling. Channel characteristics, which were power attenuation and delayed receiving of light signal, were abstracted from receivers(PDs) which were located at 0.5m above from floor. The availability of channel was verified via BPSK based communication simulation.

• The Korean Journal of Applied Statistics
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• v.1 no.2
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• pp.82-90
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• 1987

모든 과학기술지식은 객관성을 지닌 관찰과 실험과 측정에 의해서 이루어진다. 이렇게함으로써 과학기술지식은 재현성과 영구성을 가져오게 되며, 올바른 전승과 누적적 발전을 가져오는데 이 과학기술지식의 질서체계를 유지하는데 근본적인 역할을 하는 것이 표준이다. 시간, 길이, 온도, 무게 등의 기본 측정단위와 광속, 중력 등의 물리화학적 상수, 법정계량단위, 각종 공업 규격, 안정 규정 등 수 없이 많은 표준은 효과적인 공동 인식과 객관적 판단의 기준으로 활용되고 있다. 현대의 과학기술이 다양하게 발전하고 이에 따라 우리의 생활도 더욱 복잡한 구조를 이루면서 표준에 대한 필요성도 더욱 높아가고 있다. 표준에 대한 깊은 생각없이도 우리는 자동차에 주유할때 표준단위를 통해 원하는 분량을 말하며, 카메라의 필름 종류를 선택할 때도 국제표준기구(ISO: International Standards Organization)의 규격을 사용하는데 익숙해져 있다. 이렇게 표준은 우리 일상생활과 밀접한 관계에 있으나 소비자 입장에서는 그 가치를 절실히 느끼지 못한 것이 사실이며 표준이 없음으로 해서 일어나는 불편과 혼란에 대해서는 무관심한 것이 사실이다. 일상생활에서 일어나는 표준의 역할을 우리가 잘 이해한다면 표준이 왜 필요한가를 쉽게 인식하게 될 것이다. 최근 정보산업이 새로운 물결로 사회전반에 영향을 미치고 있으며 이에 따라 정보의 수집, 가공, 저장 및 배포의 처리 과정에서도 제반 표준화의 필요성이 크게 대두되었다. 그 결과로 최근 10여년간에 수백종의 기술기준, 지침서 및 기본/기능 표준규격이 제정되어 왔다. 이와 같이 어떤 특별한 영역에서의 표준에 대한 요구가 있을 때 관련 규격이 제정되게 된다. 표준의 제정을 위한 다음 단계는 그 주제에 관한 표준(또는 규격)개발에 관심을 가진 사람들이 모이는 일일 것이다. 통계분야에서도 몇가지 표준화 활동이 ISO 를 중심으로 진행되고 있다. 예를 들면 실험과 검증 결과의 표현과 해석, 표본추출 방법 등에 관한 것으로 이들은 통계의 응용분야에서 꼭 필요한 표준이다. 구체적인 예로서 우리나라 국민의 표준체위값을 설정하기 위하여 측정조사할 때 측정방법 뿐 아니라 표본추출 방법과 통계자료 처리과정의 표준화가 이루어 지지 않는다면 각 기관에서 조사 발표하는 체위관계 자료가 상이하여 국가기관의 통계자료에 대한 신뢰성이 저하되고 통계값을 이용하여 의류, 신발 등의 제품을 제조하는 산업계에 혼란을 야기시킬 수 있다. 본 고에서는 ISO의 활동을 정보처리 분야에 초점을 맞춰 간략하게 설명하고 통계분야의 국제 활동을 비전문가인 필자들이 아는대로 소개하는 한편 국내활동의 필요성을 강조하여 관련 기관, 학계 및 산업계 관련전문가들의 ISO 국내활동 참여를 제의하고자 한다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.6
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• pp.561-568
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• 2011

The purpose of this study is to measure displacements that occurs on a surface and interior of slope model and the shape when the slope is destroyed at vibration experiment of the slope model using close range photogrammetry. The circle targets and sphere targets are installed on a chamber and a slope model, while the earthquake wave are applied in regular time interval. The close range photogrammetric images are acquired in each displacements step until the slope model is destroyed. Those photos are processed by image processing method and the center points of targets are automatically extracted. Furthermore, the three-dimensional coordinates of targets are calculated by image orientation and bundle adjustment processing. As a result, amount of displacement at each level is precisely measured and provided the basic information for assessing the slope stability using three-dimensional measurement of the target movement and slope destruction.

• Journal of Korean Society for Geospatial Information Science
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• v.7 no.1 s.13
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• pp.53-63
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• 1999

For the close range digital photogrammetry, multi-step procedures should be embodied in an integrated system. However, it is hard to construct an Integrated system through conventional procedural processing. Using Object Oriented Programming(OOP), photogrammetric processings can be classified with corresponding subjects and it is easy to construct an integrated system lot digital photogrammetry as well as to add the newly developed classes. In this study, the equation of 3-dimensional mathematic model is developed to make an immediate calibration of the CCD camera, the focus distance of which varies according to the distance of the object. Classes for the input and output of images are also generated to carry out the close range digital photogrammetric procedures by OOP. Image matching, coordinate transformation, dirct linear transformation and bundle adjustment are performed by producing classes corresponding to each part of data processing. The bundle adjustment, which adds the principle coordinate and focal length term to the non-photogrammetric CCD camera, is found to increase usability of the CCD camera and the accuracy of object positioning. In conclusion, classes and their hierarchies in the digital photogrammetry are designed to manage multi-step procedures using OOP and close range digital photogrammetric process is implemented using CCD camera in an integrated System.