ABSTRACT:In the 2016 fiscal year the Ministry of Land, Infrastructure, Transport and Tourism of Japan started a program integrating construction and ICT in earthwork and concrete placing. The new program named "i-Construction" focusing on productivity improvement adopts such new technologies as UAV photogrammetry and TLS. We report a field experiment to investigate whether the procedures of UAV photogrammetry and TLS following the standards for "i-Construction" are feasible or not. In the experiment we measured an embankment of about 80 metres by 160 metres immediately after earthwork was done on the embankment. We used two sets of UAV and camera in the experiment. One is a larger UAV enRoute Zion QC730 and its onboard camera Sony 6000. The other is a smaller UAV DJI Phantom 4 and its dedicated onboard camera. Moreover, we used a terrestrial laser scanner FARO Focus3D X330 based on the phase shift principle. The experiment results indicate that the procedures of UAV photogrammetry using a QC730 with an 6000 and TLS using a Focus3D X330 following the standards for "i-Construction" would be feasible. Furthermore, the experiment results show that UAV photogrammetry using a lower price UAV Phantom 4 was unable to satisfy the accuracy requirement for "i-Construction." The cause of the low accuracy by Phantom 4 is under investigation. We also found that the difference of image resolution on the ground would not have a great influence on the measurement accuracy in UAV photogrammetry.
Although zoom lens has been widely accepted in vision system, the use of zoom lens was not general in close range photogrammetry from the view point of instability by zooming. However, with the spread of consumer grade digital cameras with integrated zoom lens, in particular long range such as ×35, digital close range photogrammetry using the camera is enormously expected in various application fields. There is a large body of literature on calibration of zoom lens. However, there is still problem for effective digital photogrammetry using the camera. The problem is practical calibration model for zoom lens, in particular correction of misalignment which is caused by zoom setting. In order to resolve instability of zoom lens, and practical use of digital close range photogrammetry using zoom lens, a new calibration model is proposed in this paper based on correction of zoom lens misalignment. Furthermore, in order to evaluate the proposed calibration model for zoom lens, calibration tests were conducted using 5 kinds of consumer grade digital camera with integrated zoom lens (×3~5), 3 kinds of long range consumer grade digital camera (×12~30) and digital SLR camera with zoom lens (×11).
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