Kortowo Test Field for Testing Photogrammetric Products Accuracy – Design and First Evaluation

Abstract

<p><strong>Abstract.</strong> The continuous development of sensors, methods and technologies in the modern digital photogrammetry requires testing the quality and accuracy of software, processing workflow and products. The paper presents a new test field for performance analysis of software processing and accuracy assessment of photogrammetric 2D and 3D data collection, mapping, 3D object reconstruction and modeling based on low-altitude imagery with particular regard to unmanned aerial vehicles imagery. The first experiment was carried out using images captured by Phase One iXU-RS 1000 medium format aerial digital camera and Light Detection and Ranging (LiDAR) point cloud acquired by RIEGL LMS-Q680i airborne laser scanner. The process of complex digital processing was performed in Agisoft Metashape packages. The subblock of 169 images and 16 signalized ground points measured by Global Navigation Satellite Systems in the WGS 84 coordinate system using the Real-Time Network method were adopted in the preliminary investigations. The root mean square error RMSEXYZ on check points in the bundle block adjustment was equal to 0.032 m. Vertical deviations between digital elevation model and LiDAR point clouds belong to the range from −0.020 m to 0.020 m which is related to RIEGL LMS-Q680i accuracy and precision. Georeferenced orthomosaic was generated with ground sampling distance (GSD) equal to 0.020 m, which was the same as the GSD of input images. The high accuracy of obtained processing results is related to accuracy of initial data, and it proves the usefulness of Kortowo test field.</p>

Quality Evaluation of 3d Building Models Based on Low-Altitude Imagery and Airborne Laser Scanning Point Clouds

“…Figure 3 presents the ISOK point clouds. Gabara and Sawicki (2019b). The point cloud is characterized by a minimal density of 25 pts/m 2 and an accuracy of about 0.03 m.…”

“…Images were acquired using Phase One iXU-RS 1000 medium format digital camera. Because test objects form a small section (coverage area about 0.55 km 2 ) of the test field (Gabara and Sawicki, 2019b), so the images and ground control points (GCPs) were selected to this region (121 photos) and processed using Agisoft Metashape v. 1.7.1 application. The root mean square errors (RMSE) and reprojection error obtained in the BBA are presented in Table 2.…”

“…Figure 4 presents the computed dense point cloud of test objects and Figure 5 shows the point cloud in a wider context. The accuracy assessment of the whole block of images and comparison with LiDAR point cloud is described in (Gabara and Sawicki, 2019b…”