Geometric Quality of Orthophoto from Aerial Images Obtained by UAV^s Consumer Grade Camera: Lesson learnt Silvester Sari Sai* (1), Martinus Edwin Tjahjadi (2), Masrurotul Ajiza (3), Hery Purwanto (4)
1,2,3,4 Department of Geodesy, National Institute of technology (ITN Malang), Indonesia Malang Jl.Bendungan Sigura-gura No.2 Malang 65145
Abstract
UAVs (Unmanned Aerial Vehicles) gain wider acceptance for cadaster mapping related activities in Indonesia. This flying platform is usually equipped with consumer grades digital cameras. Such off-the shelf cameras have long been known to suffer unstable lens elements and electronics. Regardless of camera types being mounted on the UAV board, these instabilities are major impediment to attain a high accuracy of orthophoto generated from aerial images obtained by the UAV camera. Geometrical defects of those images would afflict a geometrical quality of the orthophoto which is produced by stitching and rectifying the images. This paper investigates the quality of the generated orthophoto assembled by those defected images. The quality is assessed according to the American Society of Photogrammetry and Remote Sensing (ASPRS) as well as regulation of State Minister of Agrarian standards. Flight missions were carried out to produce a 2.7cm ground sampling distance (GSD) of images. The geometric accuracies are analyzed through a provision of the independent check points (ICPs) and areas discrepancies between the ones measured using geodetic type of GPS instruments. Their RMSE figures reveal that the orthophoto map obtained by the UAV is suitable only up to a 1:500 of a map scale.
