The survey of the Basilica di Collemaggio in L’Aquila with a system of terrestrial imaging and most proven techniques

The proposed job concerns the evaluation of a series of surveys carried out in the context of a campaign of studies begun in 2015 with the objective of comparing the accuracies obtainable with the systems of terrestrial imaging, compared to unmanned aerial vehicle imaging and laser scanner survey. In particular, the authors want to test the applicability of a system of imaging rover (IR), an innovative terrestrial imaging system, that consists of a multi-camera with integrated global positioning system (GPS)/global navigation satellite system (GNSS) receiver, that is very recently released technique, and only a few literature references exist on the specific subject. In detail, the IR consists of a total of 12 calibrated cameras – seven “panorama” and five downward-looking – providing complete site documentation that can potentially be used to make photogrammetric measurements. The data acquired in this experimentation were then elaborated with various software packages in order to obtain point clouds and a three-dimensional model in different cases, and a comparison of the various results obtained was carried out. Following, the case study of the Basilica di Santa Maria di Collemaggio in L’Aquila is reported; Collemaggio is an UNESCO world heritage site; it was damaged during the seismic event of 2009, and its restoration is still in progress

Imaging rover technology: characteristics, possibilities and possible improvements

The terrestrial photogrammetric survey allows to acquire geometric characteristics of objects quickly and with handy and inexpensive hardware. Traditionally, these measurements require some hours of time between the choice of the acquisition points, the setting up of the camera, the survey of the topographic support network and subsequent processing of the acquired data. The upcoming of advanced algorithms such as "structure from motion" (SFM) [1] and the recent availability of optical cameras with increasing resolution combined with increasing resources of mass storage [1], make it possible to create dedicated hardware with potentials not possible with these technologies so far. Of particular interest in this field is the coming of so-called "imaging rovers", i.e. cameras that allow simultaneous acquisition of multiple images, covering a 360-degree panorama and in some cases, directly positioned thanks to GPS/GNSS differential receivers with centimeter accuracy. The recent availability of these innovative techniques requires careful verification to assess their capabilities, accuracy, precision and possible limitations. This work presents the first systematic verification of one of these latest generation devices in different conditions and for different applications. It has been verified that in many cases it is possible to obtain three-dimensional surveys quickly with information contents comparable to those of more expensive and less handy instruments such as terrestrial laser scanning. The development of these techniques could lead to operational simplifications and greater efficiency also in complementarity with the reliefs from UAVs that, as it's well known, show some limitations in the so-called urban canyons

La Chapelle des Dames un splendide exemple du baroque italien

Paper regarding phogrammetric and laser scanning survey of The dames Chapel (Palermo): an extraordinary example of Italian Baroc.Un des sujets les plus brûlants de la géomatique de ce début du XXIe siècle est la recherche des techniques les plus efficaces pour numériser et restituer les édifices modernes et historiques. Les premiers font l’objets de relevés pour constituer une maquette de type BIM, les seconds plus dans le cadre d’études académiques ou de documents de base pour des travaux de restoration. Le principal sujet de débat actuel peut se résumer en une phrase : « quelle technique pour quel relevé ? ». En effet, si d’un côté les relevés laser permettent de constituer des nuages de points extrêmement riches et détaillés (Costantino, 2013), il est ensuite souvent délicat de gérer correctement une telle somme de données,même à l’aide d’ordinateurs de dernière génération (Balletti, 2015). Un problème analogue se pose avec le recours — de plus en plus fréquent – à des caméras photogrammétriques embarquées à bord de drones, suivis de traitements fondés sur des algorithmes de type Structure from Motion (SFM), qui, à partir d’images multiples, reconstituent eux aussi un nuage de points.Il faut donc bien réfléchir, avant de se lancer, au type de matériel et de logiciel qui serviront à constituer la maquette (Dominici, 2013). Nous détaillerons ici l’exemple d’un site particulièrement remarquable, pour lequel trois organismes publics et une entreprise privée ont décidé de collaborer à titre gracieux, au nom de la conservation du patrimoine artistique et culturel, et du rayonnement de la ville de Palerme

Monitoraggio dinamico del Parco Ninni Cassara a Palermo attraverso un applicativo per la gestione della manutenzione

Nel corso degli anni le tecniche di monitoraggio hanno sviluppato una tendenza esponenziale verso la semplificazione e la velocizzazione, sia delle operazioni di rilievo, che di restituzione e analisi dei dati rilevati giungendo nel contempo a livelli di accuratezza sempre più spinti. Questo volgere continuo al miglioramento delle prestazioni tecnologiche e all’ottimizzazione delle risorse in termini di tempo e denaro, per gli addetti ai lavori, ha posto la moderna Geomatica in linea con la mentalità propria del terzo millennio di fare meglio e più in fretta. Tra le tecnologie che sempre più stanno prendendo campo in quest’ottica si inserisce il Mobile Mapping System che su una qualunque piattaforma mobile integra sensori e sistemi di misura atti a fornire la posizione 3D quasi-continua della piattaforma e, contemporaneamente, in grado di acquisire dati geografici senza l’ausilio di punti di controllo a terra. Il lavoro ivi presentato si inserisce in un filone di ricerca che, dal 2012 ad oggi, studia l’applicabilità e le potenzialità della tecnologia Mobile Mapping System nei diversi ambiti del monitoraggio strutturale e territoriale. In particolare si riporta il monitoraggio del parco urbano Ninni Cassarà di Palermo realizzato tramite l’IP-S2, il sistema Mobile Mapping di TOPCON, nell’ottica della realizzazione di un applicativo per la gestione della manutenzione del parco stesso

First tests of Imaging rover techniques for the geomatic restitution of a sinkhole: the test site known as “Pozzo del Merro"

The sinkhole known as “Pozzo del Merro” possesses unusual, if not unique, geological and natural features, providing an important opportunity to study the geological and hydrological characteristics of the area, and at the same time to preserve an ecosystem inhabited by species that, as far as we know, are found nowhere else. The site has been the object of numerous studies carried out by scholars from a wide range of disciplines (Floris et al. 2014), but a true morphological survey has not been performed until now due to logistical difficulties that include the lack of adequate measuring positions and the difficulty of establishing a clear view between points. The availability of an imaging rover (Trimble V10) an innovative photogrammetric multifocal instrument integrated with a GPS/GNSS double frequency receiver suggest to perform the survey to experiment this completely new technology, comparing and assessing with more consolidated methodologies. The instrument tested consists of an integrated camera system that captures a 60 MP 360-degree digital panoramas; each acquisition is performed with a total of 12 calibrated photogrammetric cameras – seven panorama and five downward-looking. The GPS accuracy (H 8 mm + 1 ppm, V 15 mm + 1 ppm; - Trimble (2016)). With this configuration, after a single photogrammetric acquisition, the position of the instrument is given, but not its azimuth, so more stations are needed. The photogrammetric automatic algorithm has extracted almost completely the parts of sinkhole without foliage cover that represents a very small area with respect to the whole sinkhole, reporting accuracy mostly lower 5-6 cm. compatible with declared accuracy for similar distances; the survey did not identify secondary emerged cavities or tunnels that had been hypothesized on the basis of those found above water. Nonetheless, due to the specific morphology of the site, the presence of other undiscovered morphological characteristics cannot be ruled out. The Imaging rover instrumentation showed that the accuracy is similar to laser scanner, the imaging rover has a wider vertical field of view, it is logistically much more versatile and it can be of strategic importance in such sites with complex morphologies. On the other hand Imaging rover has no capabilities of penetrating foliage that is a drawback, particularly in some periods of the year

Rilievo dell “Horologium Augusti” mediante differenti tecniche di fotogrammetria terrestre e loro comparazioni

Nell’ambito di una più ampia ricerca sul corretto posizionamento ed orientamento del tratto rinvenuto della meridiana nota come “Horologium Augusti” o, più comunemente, “Meridiana di Augusto”, sono state validate differenti metodologie di rilievo fotogrammetrico terrestre. L’interesse è volto tanto alla restituzione per la conservazione di un’emergenza archeologica unica al mondo, quanto all’accurata misura di alcuni particolari che potrebbero fornire ulteriori nuovi dettagli per ricostruirne con maggior sicurezza il funzionamento, il posizionamento ed alcune informazioni di geodesia storica. Tra i rilievi sin’ora eseguiti alcuni hanno utilizzato camere professionali, ma non metriche, in differenti configurazioni di focale, sia in modalità di acquisizione singola che di ripresa continua; in quest’ultima configurazione è stato rilevato tutto il percorso che dal piano campagna porta al livello della meridiana, attualmente giacente in un locale sotterraneo. Tutte queste acquisizioni sono state fotogrammetricamente trattate con pacchetti software ampiamente collaudati ed investigati in letteratura dalla quale risultano basati su algoritmi SFM. Ulteriori rilievi sono stati eseguiti con una policamera fotogrammetrica a dodici focali simultanee di tipo “Trimble V10” e trattate successivamente, sia con i software proprietari che con i pacchetti precedentemente utilizzati; i software proprietari non riportano su quale tipo di algoritmi siano basate la ricostruzione fotogrammetrica che effettuano ne questa informazione è reperibile in letteratura, ne da contatto diretto con i produttori. Le nuvole di punti cosi ottenute sono state confrontate in termini assoluti e nelle varie componenti attraverso uno specifico pacchetto “open source”