Journal of Urban Science (도시과학)

Urban Science Institute (인천대학교 도시과학연구원)
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The Construction Method of Precise DTM of UAV Images Using Sobel-median Filtering

소벨-메디언 필터링을 이용한 UAV 영상의 정밀 DTM 구축 방법에 관한 연구

  • Na, Young-Woo
  • 나영우 (세명대학교 IT엔지니어링대학 건설환경공학과)
  • Published : 2023.12.31
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Abstract

UAV have the disadvantage that are weak from rainfall or winds due to the light platform, so use Scale-Invariant Feature Transform (SIFT) method which extrude keypoints in image matching process. To find the efficient filtering method for the construction of precise Digital Terrain Model (DTM) using UAV images, comparatively analyzed sobel and Differential of Gaussian (DoG) and found sobel is more efficient way to extrude buildings, trees, and so on. And edges are extruded more clearly when applying median additionally which have the merit of preserving edge and eliminating noise. In this study, applied sobel-median filtering which plus median to sobel and constructed the 1st filtered DTM that extrude building and trees and 2nd filtered DTM that extrude cars by threshold of gradient, Analysis of the degree of accuracy improvement showed that standard deviations of 1st filtered DTM and 2nd filtered DTM are 0.32m, 0.287m respectively, and both are acceptable for the tolerance of 0.33m for elevation points of 1/1,000 digital map, and the accuracy was increased about 10% by filtering automobiles. Plus, moving things are changed those position and direction in every image, and these are not target to filter because of the characteristic that is excluded from SIFT method.

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References

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