Search results for "Photogrammetry"
showing 10 items of 142 documents
BIM and Low-Cost Survey Techniques for Building Heritage Conservation
2017
The aim of this contribution is to illustrate a methodology for the protection and management of the building heritage, adding to the historical documentary investigations, a careful phase of survey and a conscious geometric and informational modelling of the pre-existence. The focus of this work was the Tower of Vietri sul Mare: a significant example of the architectural defense strategies adopted in Salerno in the 16th century. In fact, through the creation of digital models, it would be facilitated the management of the volumetric evolution that this tower has undergone over time, ensuring a greater accessibility and an easier understanding of the transformations it has suffered.
Control of structural problems in cultural heritage monuments using close-range photogrammetry and computer methods
2005
This paper deals with the conservation of monumental buildings. Several methods used for the architectonic documentation are analysed in this study. Computers methods and close-range photogrammetry are proposed as a preventive method which allows to detect, measure and track the temporal evolution of some structural problems detected, and also to assess the degree of conservation of the materials employed. A group of monuments belonging to the Spanish historical heritage is analysed. In order to carry out the analysis a wire-frame model and a photo-realistic textured model were made. Work focused later on the area where structural problems were more acute.
A novel visual pipework inspection system
2017
The interior visual inspection of pipelines in the nuclear industry is a safety critical activity conducted during outages to ensure the continued safe and reliable operation of plant. Typically, the video output by a manually deployed probe is viewed by an operator looking to identify and localize surface defects such as corrosion, erosion and pitting. However, it is very challenging to estimate the nature and extent of defects by viewing a large structure through a relatively small field of view. This work describes a new visual inspection system employing photogrammetry using a fisheye camera and a structured light system to map the internal geometry of pipelines by generating a photorea…
Increasing the accuracy of untaught robot positions by means of a multi-camera system
2010
We aim to improve the absolute in line positional accuracy of a robot-guided effector to better than 1 mm. We do so using photogrammetric techniques and by relying heavily on simulations to fine tune each parameter and avoid weak configurations. We also use simulations to design an LED calibration object adapted to this application. A test procedure enables us to validate both the simulated results as well as the calibration procedure. The test results exceed expectations by improving the absolute positioning of a robot effector by a factor of 20.
Bed Topography Reconstruction in a Large Amplitude Meandering Flume: Application of Close Range Photogrammetry
2014
Natural rivers are characterized by continuous variations in bed topography, especially along curved reaches. High resolution topographic data are necessary to analyze the mutual interactions between the downstream flow and the cross-stream flow, which determine the distribution of the bed-shear stress along the channel. Because of the difficulty in acquiring good and accurate data in rivers, the major part of studies have been conducted in laboratory flumes. This paper reports on a laboratory study in which the automatic digital photogrammetric survey was applied to derive the high-resolution Digital Surface Model (DSM) of the bed topography in a large amplitude meandering flume. In order …
Il rilievo fotogrammetrico del Castello di Maredolce a Palermo
2014
Le tecniche di rilievo fotogrammetrico stanno trovando un sempre più largo impiego nel campo dei BB.CC. Esse, infatti, consentono una rappresentazione dei manufatti con un'elevata cura del dettaglio geometrico mediante la restituzione vettoriale ed una elevata definizione degli aspetti materici degli oggetti attraverso la realizzazione dei fotopiani, che forniscono informazioni sia metriche che qualitative dell'oggetto. Tali tecniche, pertanto, costituiscono un fondamentale strumento di supporto alle attività di diagnostica e restauro dei monumenti antichi. Il presente articolo illustra la metodologia, le fasi operative e gli strumenti impiegati per il rilievo fotogrammetrico di un edificio…
Evaluation of capabilities of fuzzy logic classification of different kind of data
2008
In this paper, in order to evaluate the capability of several data, acquired by different sensors, some object-oriented classification tests have been carried out. In particular, the results obtained with two RGB ortophotos, acquired with traditional methodology, have been compared with the ones obtained with two QuickBird images and with the ones obtained by ADS40 pushbroom sensor. The object classification is based on two next steps: The classification to objects is based on two next steps: the decomposition of the whole image in dimension objects bigger than the pixel, procedure called segmentation, and the next classification with Fuzzy logic. This approach provides more reliable result…
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…
Use of new technique of image based aimed to perspective return
2014
The diffusion of Image-based 3D modeling techniques, through image-based free, low cost and open source software, have increased drastically in the past few years, especially in Cultural Heritage domain (Architecture, Archeology, Urban planning) [2, 3]. Computer vision techniques use photographs from dataset collection to rapidly build detailed 3D models. The simultaneous applications of different algorithms (MVS), the different techniques of image matching, feature extracting and mesh optimization are inside an active field of research in computer vision. Computer vision techniques - Structure from Motion (SfM)- allow to fulfill detailed 3D models from photos dataset collections. The resul…
Integrated surveying techniques in cultural heritage documentation
2007
This paper is focused on integration between laser scanning data, CAD modelling and photogrammetric data collected during the survey of one façade of the monument called “Quattro Canti” in the historic centre of Palermo. The investigation has been directed to the production of a 3D photorealistic model of the monument. The “Quattro Canti” monument is formed by four cylindrical façades facing the square where the older streets of Palermo intersect; each façade has a symbolic reference to one of the seasons and is divided in four levels. The façade called “Canto dell’Autunno” has been surveyed both with laser scanning and with photogrammetric techniques. Laser scanning data have been collecte…