Laser scanner technology for complex surveying structures

Organized by

INTERNATIONAL …, 2002

In each intervention heading to knowledge, cataloguing, conservation, recovery and exploitation of t he environmental and architectural ass ets, survey is a catalysing element. I is a "reconstruction" of the assets , through different ways of enquiry (mensoria, historical-critical, archival, bibliogr aphical, technical, technological), carried out with different criteria and proceedings, through the analysis of the reasons for it s coming into being with the pass ing of time. Concerning the existing sit uation, the scientific debate is focused on the distinction bet ween surveying and survey since we mean by the first one the measuring aspect and by the second one the accumulation of the analysis and st udies that have been dealt with by different disciplinar y spheres (see also the final note drafted and app roved by the partecipant s at the Congress in Rome about "Document on Archit ectural Survey"). For years, surveying has been assigned to specialized architects and engineers' ability and experience, and its transcript ion has been expressed through not coded graphical forms , which aim at a representation that will be closer to iconic art than to s cience. Nowadays, surveying operation must document the metrical completeness of grafic dat a, of those concerning diagnostics, etc. It follows that sur veying must have an hypothesis of scientific nature, based upon exp erience and, therefore , upon experiment repetitiveness. Anyone who is interested in monuments's urvey, or generally in architectural and building heritage, knows well what the survey operation's value and meaning ar e. He knows how much engagement is required and how many hours of hard work on site are needed to sur vey, elaborate the data, verify and re-draw a plan, a façade, a cross-section. The bi-dimensional representat ion method, with grafic transcript ion on paper sheet, is a system which is infected by an abstract ing operation with reference to the real p erception of an As professor Migliari says "…perché -il rilievo -lo sia, è necessario che tutto l'iter della sua formazione, dalle prime ipotesi progettuali fino al risultato finale, sia accuratamente documentato; in altre parole non possiamo più ammettere che il rilievo si riduca a una ricca serie di disegni, ma deve consistere anche nelle m isure effettuat e, negli algoritmi applicati alle misure per dedurne le quantità, nell'esplicitazione degli errori residui (vedi incertezza), nella distinzione tra le parti osservate con l'ausilio degli strumenti…" ("...it is necessary that the whole passage of its [survey] forming, since the first project hypothesis to the final results, would be precisely documented, so that it [survey] will be scientific; in other words, we cannot admit any more that su rvey merely consists of a rich sequen ce of drawings, but it has to be composed of effected measurements, of algorithms applied to measurements in order to deduce their amount, of residual error's explicitness, of difference among the parts observed by instrumental aid.."). Cf.. Migliari, R., 2000. Principi teorici e prime acquisizioni nel rilievo del Colosseo. In Disegnare, idee, immagini, A. X, n. 18/19. object, so that we aim at r eplacing it by other survey methods that also allow the 3 D representation of t he work. Nowadays, on the other hand, there is a great demand for survey's result to be accept able, free from uncertainties, and in accordance with a quality certification (ISO regulations). Computers per mit a survey proceedings tra nsformation, a metamorphosis which corresponds to the different forms of digital, analytical and analogical reproduction, t hat tends towards the objects a nd architectural buildings documentation and cataloguing. A proof of that is the operating methodology, that enables to document a building in toto or partially, by using digit al and not digital images, by putting t hem together, using the rules of stereoscopy applied t o photogrammetry to build one 3D model. Then, if it is pos sible to pass from a stereoscopic model to another one, the result will be the Digital Continuous Model, a 3D reading model, that allows the metrically accurate reproduction of the object, measurable point by point. This model can be explored by means of a computer, a n active screen and a pair of pa ssive glasses. At the present time, these systems are supplemented with the laser scanner 3D. This is an instrument tha t employs two combined methodologies: the first one bas ed on diastimeters which aim at obtaining the measurement of dis tances, and the other one based on scanning. Thinking of surveying a monument as great as Colosseum by a traditional method might dishear ten you because of the operations' complexit y, whereas, if the methodology applied is the scanning one based on a pola rized laser light ray, it is less complex than you can expect it to b e. The "pencil" of rays flows across the whole surface and captur es, point by point, its polar co-ordinates which are afterwards t urned into Cartesian coordinates, having their s tarting point in t he loud station one.

Computer Applications in Archaeology 2012. CAA 2012, Southampton, Vol. II, 2013

This paper presents the work of 3D recording and geometric documentation of part of the walls of “Ciudad de Vascos” through specific methodologies of Archaeology of the Architecture, with the objective to obtain ‘quickly’ the individual measures of every element whichcompose the wall. We carried out a topographical survey with a TLS (LeycaScanStation C10), for the geometric and volumetric reconstruction; in addition we used a GPS to give absolute coordinates to the work. We obtained the 3D textured model and a series of plans or sections, like first results of the project, as well as a series of orthoimages that will support to the archaeological study. Finally, we used techniques of digital image processing, mainly: image enhancement, edge detection and filters, in order to ‘automate’ the process of defining structural elements to obtain the measurements requested.

CIPA, 2003

We present here the first steps towards the development of a tool for architectural and patrimonial survey which combines the laser scanning techniques, close range photogrammetry and a fine analysis closer to the studied field, here architecture and archaeology. The present work is the result of a join cooperation between, INN.TEC.srl, an Italian Innovation Technology Consortium, with a Center of Competence (Topotek) specialized in geomatic problems and in particular in the treatment of cloud of 3D points coming from Laser scanner, a French CNRS laboratory working on close range photogrammetry in the context of architecture and archaeology and a laboratory from the university of Rome III, specialized in the representation of architecture. We present a knowledge based survey tool which combines mixed means of Laser Scanner and photogrammetry measurement. The statement is articulated in three phases:

2010

The aim of this paper is to demonstrate main aspects concerning contemporary methods of documentation and recording of a historical building for restoration purposes .The paper considers how terrestrial laser scanning data can assist the architect not only in the classic survey drawings, but also in the exploration of potential design alternatives concerning renovation of cultural heritage buildings. Accurate 3d models can be built from laser scanning data from the preliminary stages of survey study which can improve the understanding of the building and its behavior, in order to form restoration proposals. The building of Villa Rossa in Corfu provides the case study described in this paper, illustrating how data derived from laser scanning can form the basis for an architectural survey, Also ,in this paper, different problems are mentioned and thoughts concerning the amelioration of methodology and collaboration between architects and TLS experts.

Transactions on Engineering Technologies, 2017

The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 2012

The field of Cultural Heritage has inspired, in the course of last few years, an interest more and more important on behalf of scientific community that deals to survey. The idea that knowledge of a site doesn't apply only to its history but must necessarily include its characteristics of position, shape and geometry, is gathering pace. In Geomatic science the field of cultural heritage benefits to an integrated approach of techniques and different technologies. Every cultural site in fact, is a case in itself, with its own characteristics, problems and specificness. Current techniques offer opportunity to achieve new ways of representation and visualization of cultural site, with the aim of a better metric description. This techniques are powerful tools for analysis of sites and supports to activity of reconstruction and repair. Biggest expectations in this field is laser three-dimensional scanning technique; a system which is able to operate in a methodical way in speed of acquisition and in possibility to access data in real time. Documentation and filing of state of a monument or site is essential in case of reconstruction or conservative project. Possibility to detect very complex geometries with great accuracy allows an in depth study of constructive techniques, making analysis of geometrical details easier which is, with traditional techniques, difficult to achieve. Biggest problems about use of laser scanner survey are graphic outputs for restorers and architects, in fact they often don't know real potential of this techniques, methodologies and functionalities and they expect traditional outputs such as floor plans, cross sections and front elevation of cultural asset. Present study is focused on finding a workflow to support activity of study, restoration and conservative project of cultural heritage, extracting automatically (or with a limited manual operation) graphic outputs from laser scanner survey. Some procedure was tested on two case study the Siviller Castle (XV century), situated in Villasor, a city near Cagliari (Sardinia, Italy) and the tower bell of Mores, near Sassari (Sardinia, Italy). The cultural sites were surveyed with laser scanner Focus 3D by Faro and to process clouds point we were used the JRC 3D Reconstructor software * Corresponding author. This is useful to know for communication with the appropriate person in cases with more than one author.

Spilamberto is a little country near Modena (Italy), that expanded all around the original medieval Castle. Rocca Rangoni was a part of this Castle, was built at the beginning of XIII century and was modified till to have actual look. When in 2005 the Rocca was bought from the Common of Spilamberto, the Administration decided to open the building and its Park to the citizens. The complicated shape of the buildings and of their round places (Park, square and Castle), the absence of any previous survey and the need to reconstruct the geometry of the places in not too much time, obliged, step by step, to use and couple different techniques. This choice proceeded not only from the scale of representation, but also from environmental and morphological conditions of the places. In particular, the main purpose of our written communication is to show, through a concrete example, how to use a large quantity of laser scanner data to integrate and check a survey executed with traditional techniques (geometric, topographic, photogrammetric and GPS survey), both to architectonic and urban scale.