Monitoring and Computation of the Volumes of Stockpiles of Bulk Material by Means of UAV Photogrammetric Surveying

Abstract

The monitoring and metric assessment of piles of natural or man-made materials plays a fundamental role in the production and management processes of multiple activities. Over time, the monitoring techniques have undergone an evolution linked to the progress of measure and data processing techniques; starting from classic topography to global navigation satellite system (GNSS) technologies up to the current survey systems like laser scanner and close-range photogrammetry. Last-generation 3D data management software allow for the processing of increasingly truer high-resolution 3D models. This study shows the results of a test for the monitoring and computing of stockpile volumes of material coming from the differentiated waste collection inserted in the recycling chain, performed by means of an unmanned aerial vehicle (UAV) photogrammetric survey and the generation of 3D models starting from point clouds. The test was carried out with two UAV flight sessions, with vertical and oblique camera configurations, and using a terrestrial laser scanner for measuring the ground control points and as ground truth for testing the two survey configurations. The computations of the volumes were carried out using two software and comparisons were made both with reference to the different survey configurations and to the computation software.

Evaluation of Uav-based Dem for Volume Calculation

“…Surface-volume ratio is one of the factors that taken into account in this study, the smaller the surface volume ratio, the more accurate the volume as shown in (table 2). This is also explained by (Tucci et al, 2019), as the surface-volume ratio decreases, the computed volume will be more accurate. The impact of flying height is also considered, the higher flight provides larger area coverage, but with larger value of ground sample distance GSD too.…”

“…There are four most frequently used methods for volume computation for different purposes which are : (Tucci et al, 2019) (Julge et al, 2019): 1. Cross sectional method.…”

“…The prisms method comprises of the definition of two surfaces, determined by using of interpolation of three-dimensional spatial data, one of them is the natural surface (upper surface) and the second one is the reference surface or base surface or design surface (lower surface); the quantity enclosed by these two surfaces is discretized into elementary prisms with a triangular base as shown in Figure 7 or trapezoidal prisms from which volume is computed using the following formula 1 (case of a triangular prism): (Tucci et al, 2019)…”

“…The volumes of three earth piles were compared by both methods, and the results agreed with each other within 59 m3(8%) for Pile 1, 93 m3(9%) for Pile 2, and 14 m3(16%) for Pile 3. (Tucci et al, 2019), UAV system was used for monitoring and computing stockpile volumes of bulk materials. The ground control points GCPs for geo-referencing were obtained from the 3D point model which was generated with terrestrial laser scanning.…”

“…For instance, (Ulvi̇, 2018), analyzed the utility of unmanned aerial vehicle in volume calculation, while (Akgul et al, 2017) conducted a research on the assessment of DEMs derived from both UAV and Global Navigation Satellite System (GNSS) for earthwork computations. Furthermore, (Tucci, Gebbia, Conti, Fiorini, & Lubello, 2019) used UAV system for monitoring and computing stockpile volumes of bulk materials etc., therefore the accuracy of DEM is an important subject to be studied in volume calculation. The main aim of this paper is to evaluate the accuracy of volume that obtained by using Digital Elevation Model (DEM) derived from UAVs images at different flight heights.…”