Ground volume assessment using ’Structure from Motion’ photogrammetry with a smartphone and a compact camera

Abstract

The article describes how the Structure-from-Motion (SfM) method can be used to calculate the volume of anthropogenic microtopography. In the proposed workflow, data is obtained using mass-market devices such as a compact camera (Canon G9) and a smartphone (iPhone5). The volume is computed using free open source software (VisualSFMv0.5.23, CMPMVSv0.6.0., MeshLab) on a PCclass computer. The input data is acquired from video frames. To verify the method laboratory tests on the embankment of a known volume has been carried out. Models of the test embankment were built using two independent measurements made with those two devices. No significant differences were found between the models in a comparative analysis. The volumes of the models differed from the actual volume just by 0.7‰ and 2‰. After a successful laboratory verification, field measurements were carried out in the same way. While building the model from the data acquired with a smartphone, it was observed that a series of frames, approximately 14% of all the frames, was rejected. The missing frames caused the point cloud to be less dense in the place where they had been rejected. This affected the model’s volume differed from the volume acquired with a camera by 7%. In order to improve the homogeneity, the frame extraction frequency was increased in the place where frames have been previously missing. A uniform model was thereby obtained with point cloud density evenly distributed. There was a 1.5% difference between the embankment’s volume and the volume calculated from the camera-recorded video. The presented method permits the number of input frames to be increased and the model’s accuracy to be enhanced without making an additional measurement, which may not be possible in the case of temporary features.

Evaluation of the Volume Measurement Optical Method Suitability for Determining the Relative Compaction of Soils

“…This article describes the feasibility analysis of the optical volume measurement method (SfM based) in order to determine the state of soil compaction. Previous studies on the accuracy of this type of models used in ground volume determining gave promising results [5]. The insights presented in this paper shows the high potential of application of the optical method in innovative procedures of soil compaction testing.…”

“…However it should be noted, that in compaction testing (considered in our work), required volume assessment accuracy is higher. Another example of ground volume assessment using SfM is work of Wróżyński et al [5]. They conduct different scale tests (small embankment -in laboratory and field embankment).…”

Quantitative Landscape Assessment Using LiDAR and Rendered 360° Panoramic Images

“…Mesh files allowed us to reconstruct the topography and low, medium, and high vegetation and buildings. The process of converting point clouds to meshes was conducted in CloudCompare v.2.1 (https://www.danielgm.net/cc/), which is an open-software project for 3D point cloud processing that provides a set of tools for managing and editing point clouds and triangular meshes [38]. The process consists of rasterization of the point cloud with specified resolution and then converting it to a mesh in the form of TIN.…”

Mediterranean intermittent rivers and ephemeral streams: Challenges in monitoring complexity

“…SfM photogrammetry develops 3D structures from 2D image sequences by automatically matching conjugate points between scenes acquired from different angles (Fonstad, Dietrich, Courville, Jensen, & Carbonneau, 2013;Woodget et al, 2015). SfM is increasingly becoming more popular amongst scientists due to its affordability and the existence of easy-to-use commercial and open source software applications that allow even nonscientists to build three-dimensional models of surface features which are subjects of scientific research (Wróżyński, Pyszny, Sojka, Przybla, & Murat-Blażejewska, 2017). SfM has been used in a vast array of ecohydrological and river management applications such as for the observation of different river stages (Duró, Crosato, Kleinhans, & Uijttewaal, 2018;Niedzielski, Witek, & Spallek, 2016), analysis of feedbacks between fluvial geomorphology and riparian vegetation (Hortobágyi et al, 2017); floodplain inundation mapping (Schumann, Muhlhausen, & Andreadis, 2019) and river management and restoration (Kubota, Kawai, & Kadotani, 2017;Marteau, Vericat, Gibbins, Batalla, & Green, 2017).…”