JAUE2018-048 A Study on the Forest Ortho Photo Construction of Based on UAV According to Flight Altitude and Overlap

Abstract

Currently, aerial photographs are being used to construct spatial information on the territory of the country, but it is difficult to acquire the latest spatial information according to the continuous change of terrain. In order to solve these problems, studies on terrain analysis or ortho photo production using UAV are underway. However, it is difficult to produce ortho photo from forest rather than the downtown when performed the image matching of using photos acquired based on UAV. Therefore, in this study performed a study on the forest ortho photo construction of based on UAV according to flight altitude and overlap. Three each different flight altitudes (100m, 120m, 140m) and overlaps (F-O: 7585%, S-O: 6070%) were selected in consideration of previous studies and target terrain. A total of 9 aerial photographs were taken to construct 9 forest ortho photo. As a result of constructing forested orthographic image, if the terrain height (6070m) of the forest is high, even with a many number of photos the image matching is not performed well in the 100m and 120m sections (Case 16) where the flight altitude is low. Image matching of ortho photo in 140m sections (Case 7~9) with relatively high flight altitude performed well. Among them, Case 7 (flight altitude of 140m, 85% of frontal overlap, 70% of side overlap) was 100% image matching. Case 7 was the most efficient when considering the number of pictures, working time, and image matching. Therefore is the most effective when the minimum flight altitude is 140m, 85% of frontal overlap, and 70% of side overlap when constructing forest spatial information using UAV.