2021 Volume 77 Issue 2 Pages I_697-I_702
In this study, we devised a monitoring method for simultaneously estimating elevation, median grain size (D50), and Arcuatula senhousia distribution using Unmanned Aerial Vehicle (UAV) aerial images of tidal flat fisheries in the Konagai sight frontage of Isahaya City, Nagasaki Prefecture. The elevation of the tidal flat was estimated using Agisoft photoscan, and the D50 was estimated based on the reflectance obtained from the aerial images. In the elevation estimation, the bias was about 0.017m, and the D50 was correlated with the reflectance with R2 =0.615 (N=9). The detection accuracy of the Arcuatula senhousia distribution was found to be more than 70% at an altitude of 5~20m with 12-megapixel camera and decreased to less than 50% at an altitude of 30m or higher, and more than 60% at an altitude of 40m with 50-megapixel camera and decreased to less than 60% at an altitude of 50m. In addition, by examining the relationship between the estimated spatial distribution of each parameter, we were able to identify the area where Arcuatula senhousia tends to occur.
