Rolling Shutter Effect on the Accuracy of Photogrammetric Product Produced by Low-Cost UAV

Abstract

Low-level cameras are generally used in low-cost UAVs employed for photogrammetric product generation. Although such cameras have advantageous features in terms of flight time and maneuverability thanks to their light weight in a compact structure, they have also some limitations. These sensors are generally operated by rolling shutter which affects the image geometry. Unlike global shutter, a camera with rolling shutter creates the photograph by scanning line by line. In this study, two flights were performed by means of DJI Phantom 4 Pro to investigate the rolling shutter effect on the accuracy of photogrammetric product. Study area was a part of approximately 60 ha of Tasliciftlik Campus, Tokat Gaziosmanpasa University. Average speeds of the platform during photography were 8 m/sec and 12 m/sec. Obtained data were evaluated according to SfM workflow. The orthophotos of the study area were produced from aerial photographs both with and without rolling shutter correction by using photogrammetric software. 24 ground control points located in the study area were used to strength the model and to make accuracy assessment. According to the results, total root mean square error values were improved from 6.33 cm to 4.78 cm and 7.01 cm to 4 cm for the flights pertaining to the 8 m/sec and 12 m/sec, respectively. Thus, it can be said that better accuracy values can be obtained when rolling shutter correction are implemented during the process. Lower speeds may require multiple flight tasks depending on the extents of the study area. Therefore, it is more reasonable to fly at higher speeds and then apply rolling shutter correction to complete field work in less time.