1,720,980 research outputs found
Thermal monitoring using an ASTER image
No full textThe research is focused on the study of the applicability of remote sensing techniques (specifically using ASTER data) for marine environmental analysis, relative to the determination of the surface temperatures. Using a multitemporal approach, two images (classified as level-1B), acquired in August 2000 and in 2005, were considered. The thermal maps were realized by means of the emissivity spectral normalization method, defining the thermal gradients in the area under investigation. The spatial and temporal anomalies related to the temperature distribution were highlighted; these anomalies represent an important parameter for the identification of probable groundwater pollution and soil contamination. To define the map of the surface temperature using thermal infrared ASTER channels, a numerical model dedicated to ASTER data was implemented during the experimentation. This model is based on the principle of interpolation of the type "least square interpolation (linear)," and it implies a reduction in the number of unknowns to obtain an acceptable solution to the problem. This experimental model has provided good results in the phase of implementation and in the tests on a synthetic image that were simulated in the laboratory. However, further verifications and modifications are necessary for the processing of real ASTER images
RILIEVI FOTOGRAMMETRICI E TLS FINALIZZATI ALL’INCIDENTISTICA STRADALE
No full textUn 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
Integrated survey to extract date for structural investigations
No full textThis 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
Production of DTM quality by TLS Data
Full text linkA 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
Integrated survey for quarries monitoring
No full textIn Puglia region the activities of survey and georeferencing in the monitoring of quarries are regulated with the executive decree D.D. 38/DIR/2012. The topographic operations required concern the territorial framework and the detailed topographic survey for geometrically defining the site and the calculation of the amounts of extracted material. In order to meet the above-mentioned requirements with a continued monitoring activity, the authors have carried out a integrated surveying procedure which, beginning with operations and activities during the initial phase relative to 2012, has permitted, in later phases, work only in the area involved in excavation, and the verification over time of their global variations. This allowed the georeferencing and timereferencing of the 3D models with a resolution consistent with the required scale of representation
Terrestrial LiDAR survey of archaeological site for prototyping
No full textUnder the LEADER + Puglia 2000/2006 project, the Community Initiative Programme aimed to promote the integrated,
endogenous and sustainable development of rural areas and enhancement of specific experiences with the external territories. A
terrestrial lidar survey of a protohistoric settlement dating from the period between the Bronze Age to the Iron Age (XVIII-VIII
century B.C.) has been conducted. The possibility to exploit, and make available at the same time, this very perishable settlement
(sandy site) took a survey of high detail aimed to the realization of a copy of the excavation to be placed in situ. Given the
complexity, for some areas, such as the furnace, an integration of lidar data with those from photogrammetric technique was
necessary. The integrated survey allowed to return a 3D numerical model aimed at the next step of prototyping in 1:1 scale
EVALUATION OF REFLECTANCE FOR BUILDING MATERIALS CLASSIFICATION WITH TERRESTRIAL LASER SCANNER RADIATION
Full text linkThe main purpose of this work is the evaluation of the potential of Terrestrial Laser Scanning (TLS) technology to perform a reflectance analysis of scanned objects. A laser beam, having a coherent beam in the field of visible light (wavelength between 532nm and 680 nm), can lead to optical diffraction phenomena that allow a correlation between the degree of crystallinity of solids (in particular dispersed crystalline materials) and its reflectivity. Different materials with known crystallinity values have been examined and the diffraction value has been analysed for two types of lasers, one pulsed and the other phase measurement, with two different acquisition conditions (nadiral and oblique position). The results demonstrated the correlation by verifying that the incident laser light beam is more refracted by materials with a higher degree of crystallinity than less crystalline or amorphous materials
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