Search results for "Structure from motion"
showing 10 items of 44 documents
Integration of terrestrial laser scanning and UAV-SFM technique to generate a detailed 3D textured model of a heritage building
2020
The digital twin is among the Top 10 of the strategic technological trends for the period 2007-2019, and it represents a powerful tool for the conservation and enhancement of cultural heritage. It reproduces with "precision" a physical asset, thus allowing to investigate its structure and to analyze the deformations that occur over the years. Various techniques have been introduced to obtain high-resolution 3D models. Among these, the Terrestrial Laser Scanner (TLS) is widely recognized as the gold standard to generate accurate 3D metric reconstructions. TLS allows acquiring a lot of data (point cloud) in a fast way, being not in physical contact with the objects of investigation. By integr…
Rainfall simulation and Structure-from-Motion photogrammetry for the analysis of soil water erosion in Mediterranean vineyards
2016
[EN] Soil water erosion is a serious problem, especially in agricultural lands.Among these, vineyards deserve attention, because they constitute for the Mediterranean areas a type of land use affected by high soil losses. A significant problem related to the study of soil water erosion in these areas consists in the lack of a standardized procedure of collecting data and reporting results, mainly due to a variability among the measurement methods applied. Given this issue and the seriousness of soil water erosion in Mediterranean vineyards, this works aims to quantify the soil losses caused by simulated rainstorms, and compare them with each other depending on two different methodologies: (…
Crowdsourcing Cultural Heritage: From 3D Modeling to the Engagement of Young Generations
2016
Monitoring, digitizing and archiving museum artworks represent an important socio-cultural accomplishment and an overcoming in digital preservation today. Cultural heritage is constantly under threat of terrorist attacks and natural disaster. The high costs related to documentation task have prevented a constantly and massive survey activity. The low cost 3D image based acquisition and elaboration techniques of an object, allow to carry out a 3D photorealistic model in a short time. Therefore, a lot of museum adopted these techniques for the artworks archiving. Crowdsourcing activities can significantly speed up survey and elaboration procedures. If, on the one hand, these initiatives can h…
2015
In this study we present a hyperspectral flying goniometer system, based on a rotary-wing unmanned aerial vehicle (UAV) equipped with a spectrometer mounted on an active gimbal. We show that this approach may be used to collect multiangular hyperspectral data over vegetated environments. The pointing and positioning accuracy are assessed using structure from motion and vary from σ = 1° to 8° in pointing and σ = 0.7 to 0.8 m in positioning. We use a wheat dataset to investigate the influence of angular effects on the NDVI, TCARI and REIP vegetation indices. Angular effects caused significant variations on the indices: NDVI = 0.83–0.95; TCARI = 0.04–0.116; REIP = 729–735 nm. Our analysis high…
Da Ernesto Basile al nodo stradale: rilievo, ridisegno e studio del Monumento ai Caduti di piazza Vittorio Veneto a Palermo
2015
Per commemorare la battaglia del 27 maggio 1860, L’Amministrazione di Palermo nel 1910 decise di realizzare un monumento. Si scelse il centro di una grande piazza circolare che avrebbe costituito la parte terminale di una elegante arteria ai margini della città a cui il monumento avrebbe fatto da fondale. La realizzazione del monumento fu affidata a Ernesto Basile che progettò anche la sistemazione a giardino del piano, oltre il quale correva una strada circolare che delimitava e concludeva la piazza. Nel 1927 il Comune decise di dedicare il monumento ai Caduti della Grande Guerra e chiese a Basile di aggiungervi una quinta architettonica, un’esedra semicircolare a colonne che, separando il…
A Maximizing Hydraulic Radius (MHR) method for defining cross-section limits in rills and ephemeral gullies
2021
Abstract In this paper, a new method for determining the cross-section limits in rills and ephemeral gullies is proposed. This method is based on the estimate of the actual depth ha of each cross-section, which is the particular depth distinguishing the channel from the hillslope areas. The analysis showed that the actual depth corresponds to a particular bank slope sta occurring for the maximum value of the hydraulic radius R. The method was applied using a volumetric approach for calculating the hydraulic radius as the ratio between the volume of the whole investigated channel and its boundary lateral surface. The value of the bank slope st was derived by the DEM of the whole channel late…
Image-based 3D reconstruction using traditional and mobile-phone data-sets for road pavement distress analysis
2021
The issue of road networks being in deplorable conditions is one that is widespread globally. One of the main precursors for this is that when preparing maintenance management systems, many road agencies rely on data which is often outdated or inaccurate. This is due in many cases to insufficient budgets which are unable to adequately address both maintenance and rehabilitation. It is therefore critical that road agencies have better tools at their disposal to help combat these issues. One of the possible techniques that have been identified is the use of structure from motion techniques to adequately identify road pavement distresses. This paper advances previous work in this area and expl…
Finding Possible Weakness in the Runoff Simulation Experiments to Assess Rill Erosion Changes without Non-Intermittent Surveying Capabilities
2020
The Terrestrial Photogrammetry Scanner (TEPHOS) offers the possibility to precisely monitor linear erosion features using the Structure from Motion (SfM) technique. This is a static, multi-camera array and dynamically moves the digital videoframe camera designed to obtain 3-D models of rills before and after the runoff experiments. The main goals were to (1) obtain better insight into the rills
Testing the use of an image-based technique to measure gully erosion at Sparacia experimental area
2017
The first part of this investigation was aimed at testing the use of a three‐dimensional (3D) digital terrain model and a quasi‐tridimensional (2.5D) digital elevation model obtained by a large series of oblique images of eroded channels taken from consumer un‐calibrated and non‐metric cameras. For two closed earth channels having a different sinuosity, the ground measurement of some cross sections by a profilometer (P) was carried out and their real volume was also measured. The comparison among the three methods (3D, 2.5D, and P) pointed out that a limited underestimation of the total volume always occurs and that the 3D method is characterized by the minimum difference between measured a…