• Title/Summary/Keyword: Digital orthophoto

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Digital Orthophoto Generation from LIDAR Data (LIDAR 데이터를 이용한 수치정사사진의 제작)

  • 김형태;심용운;박승룡;김용일
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.20 no.2
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    • pp.137-143
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    • 2002
  • In this study we generated digital orthophoto from LIDAR data. To generate digital orthophoto, we make TIN from raw laser scanning data(XYZ point data) and compiled DSM from this TIN. In this procedure much noise appeared along the break lines in DSM and this can give bad effect to the quality of digital orthophoto. Therefore, we applied various techniques which can refine the break line. In the result, we concluded that the fusion of LIDAR DEM of lowland and extracted buildings was adequate to generating DSM. So we generated the digital orthophoto from DSM generated from this technique. In the result of quality test, the positional accuracy of this digital orthophoto was better than the positional accuracy of 1:5,000 map.

Detecting and Restoring the Occlusion Area for Generating Digital Orthophoto (대축척 정사보정영상 생성을 위한 폐색지역 탐지 및 복원)

  • 조우석;장휘정
    • Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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    • 2003.10a
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    • pp.237-242
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    • 2003
  • During the past, digital orthophoto is generated for rural area or low resolution image, because the accurate extraction of DEM is difficult for urban area. But, nowadays, high resolution DEM by ALS system starts to become available for urban area, so the importance of large scale digital orthophoto generation becomes increasing. In this paper, we propose and describe effective algorithm for detecting occlusion area and not only restoring occlusion area but also processing null pixels by occlusion area for minimizing the heterogeneity of digital orthophoto. With proposed algorithm, we detected occlusion area due to height of structures such as buildings, bridges, etc, and restored occlusion area using reference image. Also, The homogeneity of generated digital orthophoto was improved by using brightness correction.

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A Study on the Production of Orthophoto Map from Digital Imagery Data of SPOT Satellite (SPOT 위성의 수치영상자료를 이용한 정사투영사진지도의 제작에 관한 연구)

  • Yeu, Bock-Mo;Sohn, Duk-Jae;Park, Joung-Nam;Jeong, Soo
    • Journal of Korean Society for Geospatial Information Science
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    • v.1 no.2 s.2
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    • pp.83-96
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    • 1993
  • The orthophto map is seen as the form of picture with the uniform reduced scale as the current terrain map. Thus it provides a reasonable feeling of scene and is easy to be interpreted. Furthermore, digital orthophoto is currently used as the basic terrain information data of the Geo-Spatial Information System(GSIS). Therefore, the orhtophoto map has high potential use as a future terrain map. This paper studies the method of producing orthophoto map by using the digital satellite imagery data taken from SPOT satellite of France. The production of orthophoto map requires the process of generating orthophoto imagery with digital elevation model, which process is called digital differential rectification. As the final accuracy of orthophoto map depends on that of digital elevation model, the precise and efficient production method of digital elevation model should be preceded. This study investigated the method of producing digital elevation model directly from SPOT satellite imagery and generated ortho-image by resampling the original SPOT imagery through digital differential rectification. Finally, Simple orthophoto map was made by overlaying the ortho-image and the contour map from digital elevation model.

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A Study on Application of PC Based Digital Photogrammetric System - Focusing on Producing Digital Map, DEM and Orthophoto - (PC 기반 수치사진측량시스템의 활용방안에 관한 연구 - 수치지도, DEM, 정사영상 제작을 중심으로-)

  • Park Byung Uk;Seo Sang Il
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.23 no.3
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    • pp.303-312
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    • 2005
  • Digital map, DEM and orthophoto were produced by using PC based digital photogrammetric system and aerial photo images that were obtained with scale of 1/5,000 and scanning density of 1200dpi and 600dpi, and the accuracies of these outputs were evaluated by various methods. Non-skilled operator produced digital map with PC based digital photogrammetric system and aerial photo images scanned by 1200dpi. The results showed that it was impossible to insert contour lines, but the rest elements could be drawn with the accuracy of 1/1,000. In automatic generation of DEM, scanning density of aerial photo and grid interval of DEM didn't affect the accuracy of DEM. In production of orthophoto, we could know that the larger grid interval of DEM, the lower accuracy of orthophoto, but scanning density of original image had more effect on quality of orthophoto. By the way, accuracy comparison between orthophoto and digital map with same check points showed that orthophoto was more accurate than digital map, and orthophoto could be used in more diverse areas. Hereafter in civilian part, aerial photo image and PC based digital photogrammetric system could make practical application of data correction and update in GIS.

A Study on Producing Digital Orthophoto Cadastral Map of Waterfront (항공사진에 의한 수변구역 수치정사영상지적도 제작에 관한 연구)

  • Kim Kam Lae;Hwang Bo Sang Won;Lim Gun Hyuk;Park Se Jin
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.22 no.4
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    • pp.349-357
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    • 2004
  • In order to manage the waterfront efficiently, we are to find the efficiency of producing method for digital orthophoto that presents natural form on lands and digital orthophoto cadastral map that presents the range of physical situation and property on lands in this study. Through this study, We can check that digital orthophoto cadastral maps for the boundary management of the waterfront are utilized widely at various field except the main purpose. Thus, we resolve the leading subjects that include the accuracy evaluation on produced maps and the bond edge of map sheet for the cadastral maps in order to drive activistic utilization and application.

Applications of Digital Orthophoto in Cadastre (지적분야에서의 수치정사사진 활용방안에 관한 연구)

  • 박병욱;김상수;최윤수;차영수
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.17 no.3
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    • pp.233-243
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    • 1999
  • In this study, sample sites are chosen where digitalized cadastral maps are available, and boundaries of forestry, farming lands, and residence are clearly distinguishable. Digital orthophotos, produced from aerial photographs, are overlaid with digitalized cadastral maps to grope for applications of digital orthophoto in cadastre. The conclusions and applicable fields of this study are as follows. The first. digital orthophoto is applicable to solve problems such as discordance and duplication of boundary produced in the process of digitizing cadastral maps. The second, using digital orthophoto, it is possible to extract regions where a trouble of ownership would exist and so the necessity of cadastral resurveying can be brought. The third, by overlaying digital orthophoto and cadastral map, it can be used effectively for the present situation maintenance of buildings. The fourth, because it is possible to examine current land use of each lot, digital orthophoto may contribute to decide the validity of land category on cadastral map.

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A Study on the Generation of Three Dimensional Orthophoto Map from Aerial Photograph by Digital Photogrammetry (수치사진측량 기법을 이용한 항공사진의 정사투영사진 지도 생성에 관한 연구)

  • 조재호;윤종성
    • 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.

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Geospatial Information Extraction by using Digital Photogrammetry (수치사진측량을 이용한 지형공간정보 추출)

  • Yeu, Bock-Mo;Kim, Won-Dae
    • 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.

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A Production of Orthophoto Map from Aerial Photos using Digital Photogrammetry Technique (수치사진측양기법(數値寫眞測量技法)에 의한 항공사진(航空寫眞)으로부터 정사투영사진지도(正射投影寫眞地圖)의 제작(製作))

  • Yeu, Bock-Mo;Lee, Hyun-Jik;Jeong, Soo;Jo, Hong-Sug
    • 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.

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The Digital Orthophoto Production by the Automative Generation of DEM using Non-photogrammetric Scanner (비측정용 주사기를 사용한 수치표고모델의 자동생성에 의한 수치정사사진 제작)

  • Park, Woon-Yong;Yi, Gi-Chul;Lee, In-Soo;Kim, Jin-Su
    • 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.

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