Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography (한국측량학회지)

Korean Society of Surveying, Geodesy, Photogrammetry and Cartography (한국측량학회)
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A Study on the Accuracy Evaluation of UAV Photogrammetry using Oblique and Vertical Images

연직사진과 경사사진을 함께 이용한 UAV 사진측량의 정확도 평가 연구

  • Received : 2021.01.27
  • Accepted : 2021.02.16
  • Published : 2021.02.28
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Abstract

As data acquisition using unmanned aerial vehicles is widely used, as one of the ways to increase the accuracy of photogrammetry using unmanned aerial vehicles, a method of inputting both vertical and oblique images in bundle adjustment of aerial triangulation has been proposed. In this study, in order to find a suitable method for increasing the accuracy of photogrammetry, the accuracy of the case of adjusting the oblique images taken at different shooting angles and the case of adjusting the oblique images with different shooting angles at the same time with the vertical images were compared. As a result of the study, it was found that the error of the checkpoint decreases as the angle of the input oblique images increases. In particular, when the vertical images and oblique images are used together, the height error decreases significantly as the angle of the oblique images increases. The current 『Aerial Photogrammetry Work Regulation』 requires RMSE (Root Mean Square Error), which is the same as GSD (Ground Spatial Distance) of a vertical image. When using an oblique images with a shooting angle of 50°, a result close to this standard is obtained. If the vertical images and the 50° oblique images were adjusted at the same time, the work regulations could be satisfied. Using the results of this study, it is expected that photogrammetry using low-cost cameras mounted on unmanned aerial vehicles will become more active.

무인항공기를 이용한 데이터 취득이 널리 활용되면서 무인항공기를 이용한 사진측량의 정확도를 높일 수 있는 방안의 하나로 항공삼각측량의 번들 조정에 연직사진과 경사사진을 같이 사용하는 방법이 제시되고 있다. 본 연구에서는 사진측량의 정확도를 높이는 데 적합한 방법을 찾기 위해 촬영 각도를 달리하여 촬영한 경사사진을 조정하는 경우와 촬영 각도가 다른 경사사진을 연직사진과 동시에 조정하는 경우의 정확도를 비교하였다. 연구결과 입력되는 경사사진의 경사가 커질수록 검사점의 오차가 줄어드는 것으로 나타났으며, 특히 연직사진과 경사사진을 같이 사용할 때, 경사사진의 경사가 클수록 높이 오차가 크게 줄어드는 것으로 나타났다. 현행 『항공사진측량 작업규정』에서는 연직사진의 GSD (Ground Spatial Distance)와 동일한 RMSE (Root Mean Square Error)를 요구하고 있다. 촬영각도 50°의 경사사진을 이용할 때 이 기준에 거의 근접한 결과를 얻을 수 있었고, 연직사진과 50°의 경사사진을 동시에 조정한 경우 작업규정을 만족시킬 수 있었다. 본 연구 결과를 활용하면 무인항공기에 탑재된 저가의 사진기를 이용하는 사진측량이 더욱 활발해 질 수 있을 것으로 기대된다.

Keywords

References

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