Terrestrial laser scanning technique has represented one of the more advances occurred in the last years in the field of data acquisition. Time-of-Flight (TOF) systems provide a fast and reliable tool to measure millions of 3D points allowing a very effective and dense measurement of the surface geometry. Nowadays, the generation of high quality 3D models is a practice applied to different kind of objects: small or medium size artworks, parts of human body, cars, buildings, civil infrastructures (like dams, bridges, plants, etc.) and whole archaeological sites as well. In most cases, in order to capture the whole object geometry a number of single scans need to be acquired from different positions and then stitched together (i.e. registered each other) to generate the full 3D model. The automatization of the registration of multiple scans acquired from a terrestrial laser scanner (TLS) still represents a very attractive research field. The chance to automatically align several point clouds would reduce processing costs in terms of time and human resources. In addition it would allow even non-specialist users to produce 3D models with good quality. This paper contributes to this research area by presenting a method for the automatic registration of very dense point clouds acquired by TLS systems. The proposed solution is an extension to large datasets of an automatic range data registration procedure we developed a few years ago for the modelling of point clouds acquired with close-range laser scanners. Such procedure, based on the spin-images (SIs) algorithm, has been then improved with the introduction of a multi-resolution method that generates a pyramid of spin-images in order to speed up the matching between adjacent scans. The results we present show that this method can be successfully applied for the automatic registration of high density laser scans of complex and large structures of Cultural Heritage. (C) 2011 Elsevier Masson SAS. All rights reserved.

The aim of the research has been the developing and implementing an algorithm for automated extraction of features from LIDAR scenes with varying terrain and coverage types. This applies the moment of third order (Skweness) and fourth order (Kurtosis). While the first has been applied in order to produce an initial filtering and data classification, the second, through the introduction of the weights of the measures, provided the desired results, which is a finer classification and less noisy. The process has been carried out in Matlab but to reduce processing time, given the large data density, the analysis has been limited at a mobile window. It was, therefore, arranged to produce subscenes in order to covers the entire area. The performance of the algorithm, confirm its robustness and goodness of results. Employment of effective processing strategies to improve the automation is a key to the implementation of this algorithm. The results of this work will serve the increased demand of automation for 3D information extraction using remotely sensed large datasets. After obtaining the geometric features from LiDAR data, we want to complete the research creating an algorithm to vector features and extraction of the DTM.

This paper presents results and remarks about the use of a GPS geodetic network for the monitoring of surface deformations ongoing in the region of Bages, Catalonia (Spain). The area under investigation presents an extensive salt formation (2100 km2) known as “Conca Potàsica”. The basin consists of a large block of potassium salts which were already used for extraction purposes in ancient times. Continuous underground and superficial mining from authorized private companies gave rise to a phenomena of subsidence in the past. This aggravated the existing natural subsidence caused by the dissolution of potassium and magnesium salts which affected many urban areas. By the second half of the twentieth century deformations of about one meter were recorded in this area. The GPS network consisting of 36 points distributed throughout the territory of Bages was firstly measured in December 2007, then a second survey took place in 2008. Results of this second campaign were compared to those of 2007 in order to detect surface deformations in the area of Bages. Statistical analysis of the position differences between the two epochs showed that significative displacements have occurred so far just for the sites actually located on thegeologically unstable subareas of the “Conca Potàsica”.

We presents some results of a survey aimed to representation of collapse of a building and the feasibility of the modellation as support of structure analysis. The survey was made on a building in Salerno, built in Art Nouveau style, named after the “Società Anonima per l’Edilizia”, which undertook its construction. The city has considerable public and residential buildings in an eclectic style, and Liberty. In June 2007 the corner part of Palazzo Edilizia fell down suddenly. The collapse occurred at the sunup, but no victims or injured people were caused only because that part of the building contained living rooms of apartments, rather than bedrooms. Was realized an integrated survey with topographic, photogrammetric and terrestrial laser scanner techniques in order to obtain the 3D model, plans and prospects and the particular of area collapsed. The results has been an aid for the structural engineers.

This paper presents some results of a integrated survey, aimed to 3Dmodeling and the subsequent representation of the collapse of partof a historical building. The survey of a building in Salerno it has beenmade, built in Art Nouveau style, has the name taken from “SocietàAnonima per l’Edilizia”, which undertook its construction. The resultshave been a support characterized by metric valence for structuralengineers who have examined the stability of the structure anddetermined the cause of the collapse. The collapse occurred duringthe night and covered the South-West corner of the building.However, there were no neither victims nor injured because the zoneof the building housed the living room or rather the kitchen, and notthe bedrooms. For this case study a integrated survey it has beenconducted; in particular, laser scanning, topographical and terrestrialphotogrammetry techniques in order to obtain the 3D model ofbuildings, plans and prospects and the particular of the collapsedarea have been adopted. The experimental algorithm, developed byauthors, in order to obtain 2D representation of whole building andthe area of collapse, it has been used. The results has been an aid forthe structural engineers. Of considerable support to the aboveanalyzes were both the topographical survey of the collapse site, thatthe laboratory tests, some of them inferred by three-dimensionalmetric knowledge and by graphical representation provided.

A procedure of calculation and experimentation addressed to a DTM extraction by TLS data has been implemented. The validation of elevation values has been realized by integrating the data collected with classical topographical and GPS observations. The results obtained allowed the assessment of the appropriate and simplified procedure for the determination of the DTM using laser technology and the possibility to improve and verify the attainable accuracy of the altitude plane. The experimental outputs have been compared with those produced by commercial software. The difference obtained is primarily concerned with the conceptual scheme applied in the definition of the grid in the algorithm of interpolation and obtainable accuracy. Moreover, after obtaining the grid by topographic survey, characterized by a high precision, it is possible to verify its accuracy.

Monitoring buildings for moving elements has been always a problem of great importance for their conservation and preservation, as well as for risk mitigation. In particular, topographic surveying allows, through the use of the principles and instruments of the geodetic survey, to control moving points which have been identified and measured. In this study case, twelve survey campaigns were done for monitoring a building located in the city of Lecce. The condominium was built five years ago on an old quarry filled with debris to allow construction. Later in time, obviously, cracks started to appear on walls within the property, and for this legal actions were taken. The survey schema adopted has been that of triangulation/trilateration, from two vertices with known coordinates. With this methodologies four cornerstones have been identified, established with forced centering on pillars with anchor plates, connected to same number of framework points, considered stable. From these, 23 control points located on the structure with rotating prisms anchored at the same manner have been surveyed. The elaboration has been carried out by generating redundancy of the measures and compensating the values with least mean squares. The results obtained by the activity of survey and elaboration have confirmed the existence of ongoing phenomena. The causes that have generated the phenomenon have been, subsequently, investigated and have been considered attributable to the existence of a sewer pipeline and a water pipeline not properly put in place and consequently broke down due to the geological characteristics of the site.

The main aim of this experimentation is the evaluation of potentialities of terrestrial laser scanner technology to carry-out, beyond topographic and morphological detection, non-invasive materic analysis of the scanned objects, with the prospective to evaluate the conservation of historical landmarks and cultural heritage of which Italy is the world leading country. Coherent lasers in the visible light range may lead to optical diffraction phenomena thus allowing for structural investigation and chemical analysis of the scanned objects. Application of LST in the visible range (λ = 585 nm) to a set of solid samples commonly applied in the construction (building) industry, differing in the crystallinity of their respective lattice, led to the following conclusions: a linear correlation has been established between degree of crystallization of solids and returning luminance of lasers after diffraction onto the solids surface; Gauss distribution of luminance data from diffraction onto less crystalline (plastics, glass) materials has been much narrow than more crystalline ones (metals, alloys, plasters). Both findings confirm that laser diffraction methods may be applied for fast materic determinations after simple LST scanning of solid samples. Bragg modeling of data, extensively applied for Xray diffraction methods (XRD), may be truly co-opted to Laser Scanning.

Un settore di grande interesse sviluppato negli ultimi anni è quello del rilievo finalizzato alla ricostruzione della dinamica di un incidente stradale, il cui compito risulta talvolta delicato e decisivo, basti pensare all’ambito giudiziario, nel quale sono coinvolti aspetti sociali ed economici, oltre che penali. Considerando il carattere multidisciplinare dell’attività di ricostruzione, emerge la necessità di una elevata specializzazione e competenza di esperti che ne effettuino le ricostruzioni. Nell’ambito del rilievo di un incidente stradale l’Ingegnere Forense, in qualità di Consulente Tecnico, ha ad oggi la possibilità di ricostruire la dinamica dell’incidente servendosi di tecnologie avanzate, le quali possono rendere le operazioni di rilievo più precise e veloci. Tra le metodologie che hanno trovato larga diffusione vi è l’integrazione tra la tecnica di rilievo Laser Scanning terrestre (TLS) e la fotogrammetria terrestre. L’applicazione condotta consiste nel rilievo di un incidente stradale simulato tra una Toyota Yaris ed una Fiat Seicento presso il Politecnico di Bari. Le analisi condotte hanno evidenziato i vantaggi, ma anche gli svantaggi delle tecniche adottate per il rilievo e la ricostruzione dell’incidente stradale. Dall’analisi condotta è emersa la possibilità di risalire al veicolo che ha prodotto le tracce sull’asfalto, alla sua velocità di marcia, all’ambientazione del sinistro, nonché la quantificazione del danno provocato.

Realizzazione e conservazione di infrastrutture. Salvaguardia e recupero del patrimonio architettonico e territoriale. Formazione continua, ricerca e sviluppo, consulenza e assistenza tecnico scientifica. Soluzioni architettoniche, ingegneristiche, archeologiche e territoriali. Servizi di rilevamento, trattamento e gestione ei dati, formazione, promozione e ricerca.