Abstract
Abstract. Using unmanned aerial vehicles (UAV) for the purposes of conducting high-accuracy aerial surveying has become a hot topic over the last year. One of the most promising means of conducting such a survey involves integrating a high-resolution non-metric digital camera with the UAV and using the principals of digital photogrammetry to produce high-density colorized point clouds. Through the use of stereo imagery, precise and accurate horizontal positioning information can be produced without the need for integration with any type of inertial navigation system (INS). Of course, some form of ground control is needed to achieve this result. Terrestrial LiDAR, either static or mobile, provides the solution. Points extracted from Terrestrial LiDAR can be used as control in the digital photogrammetry solution required by the UAV. In return, the UAV is an affordable solution for filling in the shadows and occlusions typically experienced by Terrestrial LiDAR. In this paper, the accuracies of points derived from a commercially available UAV solution will be examined and compared to the accuracies achievable by a commercially available LIDAR solution. It was found that the LiDAR system produced a point cloud that was twice as accurate as the point cloud produced by the UAV’s photogrammetric solution. Both solutions gave results within a few centimetres of the control field. In addition the about of planar dispersion on the vertical wall surfaces in the UAV point cloud was found to be multiple times greater than that from the horizontal ground based UAV points or the LiDAR data.
Highlights
For many years terrestrial LiDAR users, whether operating from a static or mobile platform, have found occlusions and shadows in their point clouds to be an obstacle in producing complete surface models
Assuming that the control points gathered by the Total Station represent the true values for the location of the building features and parking lot paint lines, it is possible to form residuals that will tell us how well the LiDAR and the unmanned aerial vehicles (UAV) data conform to reality
When comparing the dispersion of the ground-based points in the UAV data we find that they are comparable to the dispersion of points in both the vertical and horizontal objects from the LiDAR data (Figures 6 and 7)
Summary
For many years terrestrial LiDAR users, whether operating from a static or mobile platform, have found occlusions and shadows in their point clouds to be an obstacle in producing complete surface models. By combining appropriate UAVs with appropriate high-resolution non-metric cameras and appropriate software, a fast and reliable solution is possible. It will use established control coordinates to compare the UAV data from a commercially available system to data from a commercially available terrestrial LiDAR system. It will quantify the dispersion of points on both horizontal and vertical surfaces
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