• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.24 no.5
• /
• pp.389-397
• /
• 2006

The purpose of the present paper is to offer an analysis of LiDAR data processing and three dimensional terrain for Geographic Information System (CIS) applications. Generally, LiDAR survey is the method which obtains quantitative and qualitative information of the terrain using airborne laser scanning (ALS). We will get a most topographic data at a Triangular Irregular Network (TIN), Digital Surface Model (DSM) and Digital Elevation Model (DEM) using LiDAR data. We examined many factors such as visibility, hillshade, aspect and slope using DEM and DSM. The analyzing results obtained from each item are thought to be regarded as leading factors in the terrain analysis. It is to be hoped that LiDAR survey will contribute a new approach to the terrain analysis.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.12 no.1
• /
• pp.89-94
• /
• 1994

A number of the latest research projects focus on the development of real-time mapping system. Typically, these devices are used to capture land-related information in digital form from airplanes or cars. The purpose of this paper is to automatically extract the road information from the digital images obtained using the so-called "GPS-Van" which has been developed by Center for Mapping at The Ohio State University, and to propose the method for the effective storage and management of the digital data. The edges of a road can be extracted from the digital image and determined real-time 3-dimensional position by digital photogrammetry. Also, the three storage level which consists of raster data level, object-oriented data level, and vector data level in the data storage and Quadtree data structure for the effective compression and search in the data management was proposed in this paper.his paper.

• Journal of Cadastre & Land InformatiX
• /
• v.44 no.1
• /
• pp.79-96
• /
• 2014

This study presents the two major problems and those improvements of Cadastral Surveying Fee System. The system has been attempted to apply for Individual Public Land Price since 2011. To tackle those problems, this study examines a variety of literatures such as specialty publications, academic thesis, and reports from government. This study applies questionnaire survey method. And the data were collected by the personnel in charge of receiving cadastral surveying application in Gwangju and Jellanamdo branch, LX Korea Cadastral Survey Corp. In order to apply Individual Public Land Price to Cadastral Surveying Fee System, this study suggests subdivision of land at price and application of sample lot and land price standard index table. A number of curriculums provided by training institute in LX Korea Cadastral Survey Corp., education materials and cyber education method are necessary to promote awareness of personnel in charge. Publicity activities are also required to fulfill governmental basis.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.3 no.4
• /
• pp.123-131
• /
• 1983

It is a matter of great importance that the elements of error in measurements be minimized in various surveying methods. It is also essential in photogrammetry to reduce the errors of ground control coordinates as their influence on the accuracy of the results is enormous, especially when the object distance is increased. In this paper, the techniques of surveying and photogrammetry were appropriately combined to obtain three-dimentional coordinates of considerable accuracy. By observing only the related angles with theodolite were obtained to prove its effectiveness. The major advantage of the presented method is its simplicity and accuracy as only the measurements by theodolite is required.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
• /
• 2010.04a
• /
• pp.301-306
• /
• 2010

Recently GIS is not only displaying and servicing data on the 2D, but also is changing rapidly to display and service 3D data. Also 3D related technology is developing actively. For display of 3D data, terrain DTM has become a basis. Generally, to acquire DTM, users are using LIDAR data or digital map's contour line. However, if using these data for producing DTM, users need to additional cost and data lead time. And hard to update terrain data. For possibility of solving these problem, this study did DTM extraction with automatic matching for aerial photograph, and analysed the result with measurement of Orthometric height and excuted accuracy through DTM(which extracted from digital photogrammetric technique). As a result, we can get a high accuracy of RMSE (0.215m).

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.27 no.5
• /
• pp.545-553
• /
• 2009

Digital Elevation Models (DEM) is widely used in establishing the topographic profile in nation spatial information. Aerial Light Detection And Ranging (LiDAR) system is one of the well-known means to produce DEM. The system has fast data acquisition procedures and less weather-dependent restrictions compared to photogrammetric approaches. In this regards, LiDAR has been widely utilized and accepted in the process of nation spatial information generation due to its sufficient positional accuracy. However, the investigation of the accuracy of aerial LiDAR data over the area of forestation with various kinds of vegetations has been barely implemented in Korea. Hence, this research focuses on the investigation of the accuracy of aerial LiDAR data over the area of forestation and the evaluation of the acquired accuracy according to the characteristics of the vegetations. The study areas include land with shrubs and its adjacent forest area with mixed tree species. The spots for the investigation have been selected to be well-distributed over the whole study areas and their coordinates are surveyed by Global Positioning Systems (GPS). Then, the surveyed information and aerial LiDAR data have been compared with each other and the result accuracy has been evaluated. Conclusively, it is recommended that LiDAR data collection to be conducted after defoliation period, especially over the areas with broadleaf trees due to the possibility of significant outliers.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.37 no.4
• /
• pp.267-277
• /
• 2019

Photogrammetry and computer vision are identical in determining the three-dimensional coordinates of images taken with a camera, but the two fields are not directly compatible with each other due to differences in camera lens distortion modeling methods and camera coordinate systems. In general, data processing of drone images is performed by bundle block adjustments using computer vision-based software, and then the plotting of the image is performed by photogrammetry-based software for mapping. In this case, we are faced with the problem of converting the model of camera lens distortions into the formula used in photogrammetry. Therefore, this study described the differences between the coordinate systems and lens distortion models used in photogrammetry and computer vision, and proposed a methodology for converting them. In order to verify the conversion formula of the camera lens distortion models, first, lens distortions were added to the virtual coordinates without lens distortions by using the computer vision-based lens distortion models. Then, the distortion coefficients were determined using photogrammetry-based lens distortion models, and the lens distortions were removed from the photo coordinates and compared with the virtual coordinates without the original distortions. The results showed that the root mean square distance was good within 0.5 pixels. In addition, epipolar images were generated to determine the accuracy by applying lens distortion coefficients for photogrammetry. The calculated root mean square error of y-parallax was found to be within 0.3 pixels.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2021.07a
• /
• pp.53-56
• /
• 2021

국내 산업화가 들어선 후 산업화 당시 지었던 낙후된 건물의 증가에 따라 구조물의 손상 조사 및 검사 방법의 수요가 늘어나고 있다. 일반적으로 구조물의 손상은 전문 검사원이 현장에서 직접 측량도구와 시각적인 방식으로 검사한다. 그러나 전문 검사원들이 직접 조사하는 수고에 비해 균열을 검사하는 방식 자체가 단순하고, 일반 사람이 검사하기에는 객관성이 떨어지는 한계가 있어 균열을 자동적으로 검출함으로써 객관성과 편의성을 보장할 기술이 필요하다. 본 연구에서는 이미지 기반으로 다양한 환경에서의 외벽 균열을 검출할 수 있는 딥러닝 모델 개발을 소개한다. 균열 검출을 위해 다양한 외벽 균열 관련 데이터셋을 확보 및 구축하고 각 데이터셋의 검출 정보를 보완할 반자동(semi-auto) 라벨링 작업을 수행하였다. 두 번째로 기존 높은 검출 성능을 보였던 모델들을 선정 및 비교하여 YOLO v5 모델을 최종적으로 선정하였고, 도메인이 각각 다른 데이터셋에 대한 교차 학습을 통해 각 데이터셋의 mAP의 편차가 31%에서 11%로 좁히는 작업을 수행하였다. 이를 통해 실제 상황에서의 균열 영상에서 균열을 검출할 수 있는 측량 시스템을 개발함으로써 실질적인 검사의 도구로 활용될 수 있길 기대한다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.25 no.6_2
• /
• pp.653-663
• /
• 2007

The purpose of this study is to suggest concrete approaches of copyright application among various map price policies to establish the system of a digital map market, to revitalize its market, and to give the public better map services. To do this, we analyzed copyright law in Korea and the copyright protection of digital map in foreign countries firstly, investigated the applicability of copyright to the map market in Korea, analyzed the effect on this market, and suggested an direction of the revision for the Surveying law and the National Geographic Information (NGlS) law lastly. We drew several conclusions. Firstly, the protection of the rights of database makers is the best approach to protect digital maps in korea. Secondly, we need to adopt copyright to the Surveying law and the National Geographic Information Systems (NGlS) law. Lastly, establishing a copyright trust organization to improve the quality of digital maps and to manage various affairs is needed.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.28 no.1
• /
• pp.57-64
• /
• 2010

Measurements of deflection in load testing of structures are typically obtained with contact instrumentations such as LVDT (Linear-Variable Differential Transformer). LVDT only measure 1-dimensional deformation and in destructive testing is damage to instrumentation, thus prohibiting deflection when the beam is close to failure. Measurements of deflection using non-metric digital cameras are useful for load testing because there are very little cost or beam failure except for cheap targets and measurements in 3-dimensional deflection can obtained rapidly. In this research, deflection of concrete beam was measured using Nikon D80 DSLR camera, and the accuracy was evaluated with comparing the outputs to the LVDT measurements. The results show that the accuracy of terrestrial photogrammetric measurements are ${\pm}$0.5mm, ${\pm}$0.5mm, ${\pm}$0.6mm for each X, Y, Z directions, and the RMSE of comparison to LVDT is ${\pm}$0.57mm.