Search results for " Structure from Motion"
showing 10 items of 15 documents
Unmanned Aerial Vehicle (UAV) Survey with Commercial-Grade Instruments: A Case Study from the Eastern Ḫabur Archaeological Survey, Iraq
2018
Low-altitude photography in archaeology is now common practice at the scale of excavations; however, landscape-scale applications are a relatively new endeavor with promising analytical potential. From 2014–2016, an unmanned aerial vehicle (UAV) with a mounted camera was used to document sites recorded as part of the Eastern Ḫabur Archaeological Survey (EḪAS), an archaeological reconnaissance project in western Dohuk Province, Iraqi Kurdistan. The EḪAS team documented over 70 archaeological sites with the UAV, from single-phase artifact scatters, to archaeological remains with standing architecture, to tells that cover more than 30 hectares. Representative examples from this survey are pres…
Accurate keyframe selection and keypoint tracking for robust visual odometry
2016
This paper presents a novel stereo visual odometry (VO) framework based on structure from motion, where a robust keypoint tracking and matching is combined with an effective keyframe selection strategy. In order to track and find correct feature correspondences a robust loop chain matching scheme on two consecutive stereo pairs is introduced. Keyframe selection is based on the proportion of features with high temporal disparity. This criterion relies on the observation that the error in the pose estimation propagates from the uncertainty of 3D points—higher for distant points, that have low 2D motion. Comparative results based on three VO datasets show that the proposed solution is remarkab…
Impiego di 3D Web-service e software open-source nel rilievo di reperti archeologici: valutazioni metriche
2013
The Structure From Motion (SFM) algorithms derived from Computer Vision community make image-based techniquesa competitive and user friendly approach to obtain 3D information of real objects. These algorithms have been implemented in many 3D web-service and open source softwareto develop free instruments for the reconstruction of very detailed 3D digital models. Their useare becoming very common above all in archaeological studies but their potentiality for metric application have not been tested at all.The aim of the work is to investigate the quality and the accuracy of 3D models obtained through 3D web-service and SFM open source software.Different tests have been performed using some 3D…
High-resolution UAV imagery for field olive (Olea europaea L.) phenotyping
2021
Remote sensing techniques based on images acquired from unmanned aerial vehicles (UAVs) could represent an effective tool to speed up the data acquisition process in phenotyping trials and, consequently, to reduce the time and cost of the field work. In this study, we assessed the ability of a UAV equipped with RGB-NIR cameras in highlighting differences in geometrical and spectral canopy characteristics between eight olive cultivars planted at different planting distances in a hedgerow olive orchard. The relationships between measured and estimated canopy height, projected canopy area and canopy volume were linear regardless of the different cultivars and planting distances (RMSE of 0.12 m…
Using dense stereo matching techniques in survey
2013
In recent years there has been an enormous increase in the dissemination of modelling techniques known as dense stereo matching (DSM) or image-based modelling (IBM) using free, low cost, open source software, especially applications involving the survey of cultural heritage (architecture, archaeology, and town planning). The algorithms used by these software programmes process photographic datasets and provide a 3D model of the scene in question. During complex survey and 3D restitution procedures, these techniques save time (processing) and money: these advantages Can he useful to any professional. This is why it is important to identify the real potential and limits of these software prog…
Assessing Seagrass Restoration Actions through a Micro-Bathymetry Survey Approach (Italy, Mediterranean Sea)
2022
Underwater photogrammetry provides a means of generating high-resolution products such as dense point clouds, 3D models, and orthomosaics with centimetric scale resolutions. Underwater photogrammetric models can be used to monitor the growth and expansion of benthic communities, including the assessment of the conservation status of seagrass beds and their change over time (time lapse micro-bathymetry) with OBIA classifications (Object-Based Image Analysis). However, one of the most complex aspects of underwater photogrammetry is the accuracy of the 3D models for both the horizontal and vertical components used to estimate the surfaces and volumes of biomass. In this study, a photogrammetry…
Low Cost Handheld 3D Scanning for Architectural Elements Acquisition
2016
3D scanning has gone a long way since its first appearance in cultural heritage digitization and modeling. In the recent years some new low cost, fast, accurate emerging technologies are flooding the market. Envisioning the massive use of these cheap and easy to use devices in the next years, it is crucial to explore the possible fields of application and to test their effectiveness in terms of easiness of 3D data collection, processing, mesh resolution and metric accuracy against the size and features of the objects. In this study we focus the attention on one emerging technology, the Structure Sensor device, in order to verify a 3D pipeline acquisition on an architectural element and its …
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…
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…