An integrated Survey for Knowledge and Preservation of a Cultural Heritage: The Albanian Fortified Citadel of Elbasan

The Inter-Link project “Progetto pilota per la conoscenza, conservazione e valorizzazione della Kalà (cittadella) di Elbasan – Albania”, relating to the 2004-2006 triennium and co-ordinated by Prof. Roberto Pierini, aims at the study of the Elbasan fortified citadel, the Kalà, in order to preserve, restore and exploit this all-important heritage of the city. The survey and rendering of archaeological, town planning and architectural attributes will be carried out by means of innovative methods and technologies, such as photogrammetry, laser scanning and georadar. Within the limits of this project, measuring and surveying campaigns have started in April, 2006, and final, full measurements campaign in February, 2007

Accuracy Check of Road’s Cross Slope Evaluation Using MMS Vehicle

Department of Civil Engineering (DCE), seat of Topography and Photogrammetry – Pisa University, cooperating with Excellence Centre for Telegeomatics Research of the Trieste University, is developing several methods in order to evaluate road’s cross slope. This measure is performed by use of instrumentation integrated on MMS vehicle GIGI One. In particular two different approaches are followed. The first one preview using of low cost monoaxial laser scanner IBEO Automotive LD GmbH, synchronized with Applanix POS LV system. With the second one cross slope is calculated by only inertial system data, using a simplified algorithm that describes vehicle dynamics. This paper will present an accuracy control of both methods. This control is realised on two different datasets, relating to the s.s. 58 Strada Nuova per Opicina, joining Trieste to Opicina and the s.s.1 Aurelia between Rosignano and Campolecciano, near Livorno. The control compares the two method’s results systematically and preview several single point check by tests realised with classic topographic instrumentation

The use of image and laser scanner survey archives for cultural heritage 3D modelling and change analysis

Cultural heritage studies often require the analysis of buildings that have undergone several changes and alterations during their lifetime. This often implies the loss of architectural elements or the construction of new elements, which both change the characteristics of the former buildings. The recovery of lost elements or structures through virtual reconstruction is of paramount importance in both scientific and cultural applications. Novel procedures in surveying and photogrammetric processing including historical photogrammetry and historical terrestrial laser scanning offer powerful tools that enable the extraction of geometric information from historical documentation such as archival images. This paper presents the integration of a metric 3D model with information present in archival surveys of lost architectural volumes. The methodology implies the availability of historical plans representing the survey object at scales consistent with UAV surveys and featuring shared elements. The methodology used to frame these plans in the reference system of the UAV survey for an open source GIS environment is also described as well as the accuracy checks. Finally, the procedure followed for the virtual reconstruction of the Fortezza in a BIM environment, which produced a model derived from the integration of historic and current data, is described

Analisi dei dati altimetrici disponibili per il territorio comunale di Pisa

Il lavoro presenta i primi risultati di una ricerca congiunta fra il Laboratorio ASTRO del Dipartimento di Ingegneria Civile dell’Università di Pisa ed i tecnici della Direzione Ambiente del Comune di Pisa. Tale ricerca riguarda l’analisi e l’utilizzo dei dati altimetrici disponibili per il territorio comunale di Pisa. In particolare, tale analisi è condotta sui modelli digitali del terreno derivanti sia dal bando per l’Aggiornamento della Base Dati del Portale Cartografico Nazionale (PCN), emanato dal Ministero dell’Ambiente per la caratterizzazione altimetrica delle principali aste fluviali, di tutte le linee di costa e delle aree ad elevata criticità idrogeologica, sia dall’integrazione di questo bando da parte della Regione Toscana per la copertura integrale del territorio regionale. L’obiettivo iniziale della ricerca riguarda la validazione di tali modelli digitali del terreno (DTM), provenienti da rilievi laser scanner. Vengono quindi descritti e presentati i risultati delle validazioni eseguite

The accuracy analysis of lidar-derived elevation data for the geometric description of the cross-sections of a riverbed

The work stems from a joint study between the Laboratory ASTRO (Department of Civil and Industrial Engineering - University of Pisa), the municipality of Pisa and the province of Arezzo on the advanced analysis and use of digital elevation data. Besides, it is framed in the research carried on by ASTRO about the definition of the priority informative layers for emergency management in the territory, as of PRIN 2008. Specifically, this work is in continuity with other already published results concerning rigorous accuracy checks of LIDAR data and testing of the procedures to transform raw data in formats consistent with the CTR and survey data. The analysis of sections of riverbed, obtained by interpolation DTMs featuring different grid density with those detected topographically, is presented. Validation by differential GNSS methodology of the DTMs used showed a good overall quality of the model for open, low-sloping areas. Analysis of the sections, however, has shown that the representation of small or high-sloping (ditches, embankments) morphological elements requires a high point density such as in laser scanner surveys, and a small mesh size of the grid. In addition, the correct representation of riverside structures is often hindered by the presence of thick vegetation and poor raw LIDAR data filtering

UAV-BASED PHOTOGRAMMETRY AS AN INTEGRATION IN MULTI-SENSOR ARCHITECTURAL SURVEY

Current methodologies used in architectural surveys allow to obtain 3-D models featuring high precision for geometry and shape and good quality for chromatic data. Several researches are available in bibliography, showing how easily high-precision models, with high-quality photorealistic textures, can be obtained by using and combining laser scanning and terrestrial photogrammetry. Anyway, there are some contexts in which achieving good quality surveys with these techniques is logistically complex, such in the case of areas with difficult or no access (roofing, high façades, etc.). In many of these cases, a solution can be found in an innovative survey methodology, which is becoming more and more popular: Unmanned Airborne Vehicle (UAV)-based photogrammetry, with processing of data via Structure from Motion (SfM) procedures. The present paper describes a study of the integration of different survey methodologies (laser scanning, ground- and UAV-based photogrammetry, total station) in order to obtain a full featured 3-D model, whose accuracy has been checked

From survey to semantic representation for Cultural Heritage: the 3D modeling of recurring architectural elements

The digitization of Cultural Heritage paves the way for new approaches to surveying and restitution of historical sites. With a view to the management of integrated programs of documentation and conservation, the research is now focusing on the creation of information systems where to link the digital representation of a building to semantic knowledge. With reference to the emblematic case study of the Calci Charterhouse, also known as Pisa Charterhouse, this contribution illustrates an approach to be followed in the transition from 3D survey information, derived from laser scanner and photogrammetric techniques, to the creation of semantically enriched 3D models. The proposed approach is based on the recognition -segmentation and classification- of elements on the original raw point cloud, and on the manual mapping of NURBS elements on it. For this shape recognition process, reference to architectural treatises and vocabularies of classical architecture is a key step. The created building components are finally imported in a H-BIM environment, where they are enriched with semantic information related to historical knowledge, documentary sources and restoration activities

Frescoed vaults: Accuracy controlled simplified methodology for planar development of three-dimensional textured models

In the field of documentation and preservation of cultural heritage, there is keen interest in 3D metric viewing and rendering of architecture for both formal appearance and color. On the other hand, operative steps of restoration interventions still require full-scale, 2D metric surface representations. The transition from 3D to 2D representation, with the related geometric transformations, has not yet been fully formalized for planar development of frescoed vaults. Methodologies proposed so far on this subject provide transitioning from point cloud models to ideal mathematical surfaces and projecting textures using software tools. The methodology used for geometry and texture development in the present work does not require any dedicated software. The different processing steps can be individually checked for any error introduced, which can be then quantified. A direct accuracy check of the planar development of the frescoed surface has been carried out by qualified restorers, yielding a result of 3 mm. The proposed methodology, although requiring further studies to improve automation of the different processing steps, allowed extracting 2D drafts fully usable by operators restoring the vault frescoes

Computational vision in UV-Mapping of textured meshes coming from photogrammetric recovery: Unwrapping frescoed vaults

Sometimes it is difficult to represent "on paper" the existing reality of architectonic elements, depending on the complexity of his geometry, but not only in cases with complex geometries: non-relief surfaces, can need a "special planar format" for its graphical representation. Nowadays, there are a lot of methods to obtain tridimensional recovery of our Cultural Heritage with different ranges of the relationship accuracy / costs, even getting high accuracy using "low-cost" recovery methods as digital photogrammetry, which allow us easily to obtain a graphical representation "on paper": ortho-images of different points of view. This can be useful for many purposes but, for others, an orthographic projection is not really very interesting. In non-site restoration tasks of frescoed vaults, a "planar format" representation in needed to see in true magnitude the paintings represented on the intrados vault, because of the general methodology used: gluing the fresco on a fabric, removing the fresco-fabric from the support, moving to laboratory, removing the fresco from the fabric, restoring the fresco, gluing back the restored fresco on another fabric, laying the restored fresco on the original location and removing the fabric. Because of this, many times, an unfolded model is needed, in a similar way a cylinder or cone can be unfolded, but in this case with a texture included: UV unwrapping. Unfold and fold-back processes, can be especially interesting in restoration field of frescoed vaults and domes at: chromatic recovery of paintings, reconstruction of partially missed geometries, transference of paintings on surfaces, etc

VOC Air Pollution in Urban Areas – A Microscale Model experimentally validated

Previous theoretical and experimental studies (S. T. A.- Università di Pisa (DIMNP), 1998; Agostini E., M. Corezzi, I. Ciucci, M. Mazzini 2003; Agostini E., I. Ciucci, M. Mazzini, S. Strinati, 2003) even if partial, evidenced the problem of atmospheric pollution by Volatile Organic Compounds (VOC) in Livorno (Tuscany). This pollution is caused mainly by the presence of an important refinery, other industries and traffic. Other relevant VOC emission sources are linked to port activities and to numerous small companies using paints and solvents. Figure 1 shows the map of Livorno, situated on the Tyrrhenian sea. This is a simple site from the orography point of view, except for the southern zone where a promontory and a chain of hills impose a more complex pattern of air fluxes. The industrial zone is localized in the north of the map and the harbour activities along the coast (west area). It’s difficult to define a specific zone for the companies using solvents and paints, even though a grater concentration is present around the axis Viale Carducci – Piazza Repubblica – Via Grande. The map outlines also the air pollution measurement stations managed by ARPAT (points) and the meteorological stations (crosses). The simulation of the emission scenario, was done by using ISC3 (U. S. Environmental Protection Agency) code for treating diffuse sources and CALINE4 (California Department of Transportation) for those related to traffic on main roads. The research work focuses the attention on the results of model validation by experimental data obtained along the roads of the studied area. The possibility to extend the application of this model to sites with similar orography and town-planning characteristics is also discussed in the aim of obtaining information about the level of atmospheric pollution on sites where there aren’t measurement stations