• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.26 no.3
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• pp.241-253
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• 2008

Recently, it is appearing that new paradigm of urban planning that ubiquitous concept such as the u-City, uECO-City is introduced while is rising necessity about third dimensional geo-spatial information of high quality for urban area. Orthophoto can manufacture by expense and time that is less easily than digital map using personal computer even if is not highly technician and according as position relation between manmade feature and natural feature is equal, can get information of distance, angle, horizontal and vertical position coordinate of topographic, area etc.. directly through orthophoto. Also, visual effect is good that orthophoto is expressed by image and interpretation is easy to detailed part of topographic. Manufacture and practical use are consisting in various field, for it is having advantage that can recognize information effectively than digital map. Therefore, this study presents a way of generating a detailed DSM for producing a true-orthphoto of the urban area, and this study also presents a way to produce an optimum true-orthophoto for an urban area by investigating through experiment the optimum variable for the geometric and radiometric correction of the orthophoto. This study also examined the potentials of the thesis by building a 3-dimensional city model of the model region with the above thesis on optimum generating method.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.34 no.5
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• pp.535-544
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• 2016

Even though existing methods for orthophoto production using expensive aircraft are effective in large areas, they are drawbacks when dealing with renew quickly according to geographic features. But, as UAV(Unmanned Aerial Vehicle) technology has advanced rapidly, and also by loading sensors such as GPS and IMU, they are evaluates that these UAV and sensor technology can substitute expensive traditional aerial photogrammetry. Orthophoto production by using UAV has advantages that spatial information of small area can be updated quickly. But in the case of existing researches, images of same altitude are used in orthophoto generation, they are drawbacks about repetition of data and renewal of data. In this study, we targeted about small slope area, and by using low-end UAV, generated orthophoto and DEM(Digital Elevation Model) through different altitudinal images. The RMSE of the check points is σ_h = 0.023m on a horizontal plane and σ_v = 0.049m on a vertical plane. This maximum value and mean RMSE are in accordance with the working rule agreement for the aerial photogrammetry of the National Geographic Information Institute(NGII) on a 1/500 scale digital map. This paper suggests that generate orthophoto of high accuracy using a different altitude images. Reducing the repetition of data through images of different altitude and provide the informations about the spatial information quickly.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.16 no.2
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• pp.203-211
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• 1998

A traditional method to produce three dimensional orthophoto map has been studied by digital photogrammetry which decides a height by digitally searching conjugate points on the stereo image. Many researches in digital photogrammetric field are still in progress to determine conjugate points automatically. In this study, we analyze the effect of accuracy of area-based image matching with changing eight types of target area size using four types of image pyramid. The result of image matching to each method compared with 1/5,000 digital mapping data. We decided a optimal size of target area on a percentage of image matching. Digital elevation model is generated by matching results and bundle method. As a result, three dimensional orthophoto map is made in terms of digital elevation model and orthophoto.

• Journal of the Korean Society of Industry Convergence
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• v.21 no.6
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• pp.345-354
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• 2018

It is conservative to say that lots of research is performed as measures to use UAV for application to the rapid spatial information and its application is faced with settlement stage to some extent. In addition, Korea Land and Geospatial Informatix Corporation autonomously produces work regulation which is applied to every kind of orders and National Geographic Information Institute (2018) has notified public surveying work instructions about unmanned aerial device for the rapid spatial information construction. The results acquired by UAV are comprised of contents about accuracy improvements for the orthophoto when reviewing pertinent regulations. The results acquired by UAV are comprised of contents about accuracy improvements for the orthophoto when reviewing pertinent regulations. As a result, it is known that error amount has been sharply increased from 400m separation distance, and this study proposes that cross flight is able to reduce irregular error occurrence as measures to acquire stable results.

• Journal of the Korean Association of Geographic Information Studies
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• v.3 no.2
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• pp.24-36
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• 2000

This study deals with the optimal method of orthophoto products using the non-photogrammetric scanners. we scanned positive film of aerial photographs at the different resolution and producted the orthophoto using the automatically generated DEM based on the Digital Photogrammetric Workstation, considering aerial image resolutions, DEM interval, resampling method and outpixel size. As a results, the acquired accuracy was worse in horizontal, but good in vertical. So It will be expected that orthophoto using non-photo grammetric scanner is good enough for the acquisition of GIS data and the calculation of soil volumes.

• Proceedings of the Korea Contents Association Conference
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• 2006.05a
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• pp.545-548
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• 2006

It's very difficult to acquire the accurate GCP(Ground Control Point) in the urban center and forest aerial photo because of occurring of irregular multi-path error. Thr purpose of this study is to apply the GPS and the EDM system for 3D orthophoto in the small areas. GCPs surveyed by accuracy triangulation from EDM after from triangulation points to a fiducial point at study area used to GPS. And I have a comment on how to use areal orthophoto for future 3D-GIS after 3D-Modelling using areal orthophoto. As the results, EDM surveying could resolve multi-path error according to GPS surveying and It is possible for using aerial orthophoto on the basis of the 3D-GIS database.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.25 no.5
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• pp.415-425
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• 2007

In this study, we generated an orthophoto with both LIDAR data and aerial images and compared it with that generated from only the images. For the accuracy assessment of these orthophotos, we performed not only qualitative analysis based on visual inspection but also quantitative analysis by measuring horizontal inconsistency, boundary coordinates and similarity measures on buildings. Based on the visual inspection and horizontal inconsistency, the orthophoto based on LIDAR DSM appeared to be more closer to a true-orthophoto. However, the analysis on measurements of boundary coordinates and similarity measures indicates that the orthophoto based on LIDAR DSM is more vulnerable to double mapping on occluded areas. Accordingly, if we apply an effective solution on double mapping or use only the central areas of the aerial images where occluded areas are rarely founded, we can generate automatically true-orthophotos based on a LIDAR DSM.

• Journal of Korean Society for Geospatial Information Science
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• v.2 no.1 s.3
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• pp.73-80
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• 1994

Most terrain information have been generally acquired by map. Because the map presents the real terrain, not by real figure but by contours, geometric figures, symbols, texts, and colors, it is not easy to interpret the real terrain by map. For this reason, aerial photos or terrestrial photos also have been used sometimes in the terrain analysis. But photos have geometrical displacement caused by the position of camera at the exposition time and the relief of the object. So, for accurate posional analysis, orthophoto maps produced by optical rectifier have been used. But, it is hard to produce orthophoto map by optical rectifier and the process is so slow. This study aims to present an accurate and rapid method to produce orthophoto map by generating digital elevation model from stereo aerial photos on common computer using the digital photogrammetric technique and producing orthophoto map digitally using the digital elevation model.

• Journal of Cadastre & Land InformatiX
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• v.51 no.1
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• pp.125-136
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• 2021

Recently, Unmanned Aerial Vehicle utilization and image processing technology for remote sensing have diversified remarkably with Orthophoto and Digital Surface Model. In particular, It uses more application fields such as spatial information analysis and hazardous areas as well as land surveying. This study analyses the accuracy of the coordinate on Orthophoto and DSM height on slope area with high and low differences by using UAV images. As the result of this study, in the case of GCP on 2D orthophoto, the location error was not produced significantly. The vertical position of the DSM showed the highest accuracy when the height difference between GCPs is under 30m(RMSEZ=0.07m). The location of the GCPs was divided into approximately 10m, 20m, 30m, and 40m with analysis for each of the eight points of GCP and inspection points in general. This study expects that producing both horizontal accuracy of Orthophoto and vertical accuracy of DSM using UAV on the sloped area which similar to this research area will help in spatial information fields.

• Journal of Korean Society for Geospatial Information Science
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• v.7 no.2 s.14
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• pp.81-91
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• 1999

The study on the updating of the database of Geo-Spatial Information System that is necessary condition to GSIS operation have executed actively. In this study, digital orthophotos were produced by using the product of digital photogrammetry process and then multiscale digital orthophoto maps were generated tv the concept of image pyramids. The produced digital orthophoto has 2.092 meters accuracy compared to 1:5,000 topographic map. This digital orthophoto can be implemented in various Geo-Spatial Information System, providing valuable spatial reference for other objects in the database.