Integrating laser scanning, multispectral imagery and gis in c&r documentation practices: a first approach using two XVIth century wood paintings from Convento de Cristo in Tomar. (original) (raw)
Related papers
2012
This article addresses the application of geomatic technologies in the field of painting conservation and restoration (C&R). It results from collaboration between geomatic professionals and conservators-restorers and intends to gradually integrate techniques like photogrammetry, laser scanning, multi-spectral analysis or geographic information systems in the daily work of C&R. In this phase we have focused our efforts in the specific field of retable wooden painting using as case-study paintings from the XVIth century belonging to the Convent of Christ in Tomar, Portugal, that are part of a large dimension retable composed originally by twelve pieces in the deambulatory chapel of the convent church. Until now, at least in Portugal, painting C&R does not use any of the documentation standard procedures already applied in other cultural heritage fields like archaeology or architecture. The conceptual plans for future research along with the results from the laser scanning and photogra...
This work addresses the use of laser scanning systems as an imaging and 3D modeling device applied to art works, in this case Portuguese XVIth century paintings, and is part of a wider project concerning the research for potential applications of geomatic technologies in the field of cultural heritage documentation. The final goal is to create a geographical information system for supporting conservation and restoration of artworks where all the information is spatial referenced. By means of its capacity to obtain enormous quantity of 3D data from surfaces it is possible to quickly measure all the extents of the object and, if needed, its neighborhood. Another potential application is the use of this system as an imaging device. Some laser scanners are able to measure the reflectance intensity, in a specific wavelength, providing complementary information about each 3D point. Because of this relation between 3D coordinates and reflectance intensity it is possible to create orthorectified images in any desired projection plane. This experience allowed testing the system capabilities to work as an IR imaging device in the detection of painting characteristics like underdrawing, inpaintings and other useful information for painting conservation. The results from a preliminary work in two paintings from the “Convento de Cristo”, a UNESCO World Heritage site, in Tomar are presented here.
The “Convento de Cristo”, located in the city of Tomar, represents the best that has been produced in the history of Portuguese architecture. This monumental site, built between the 12th and 17th century, includes a Templar castle and a convent of the Order of Christ, and is classified as World Heritage by UNESCO since 1983. In this paper we intend to discuss the potential and usability of the methods and tools of digital photogrammetry and terrestrial laser scanning (TLS) to the recording and production of base documentation as support to heritage interventions. A set of documentary case studies accomplished in this monumental site will be presented. In these case studies documentation for stratigraphical analysis prior to Rehabilitation and Restoration planning design, was produced regarding the knowledge of the historical and cultural evolution of the site. The archaeological recording was done at the level of deposits and walls. In the same context, documentation as support to Conservation interventions was also produced. The following approaches were used: i) rectified photography as a low-cost and very practical method, ii) automatic three dimensional reconstruction from multiple images with the state-of-the-art structure-from-motion (SFM) software VSFM (Visual SFM), followed by a dense reconstruction with the multi-view-stereo software CMVS+PMVS, in a approach that minimized the processing time, maintaining quality of output, iii) TLS as a tool for geometric and radiometric survey, iv) image interpretation and processing of TLS reflectance images as a tool for the differentiation of materials and constructive systems and assessment of the conservation state. Three dimensional data enabled spatial comparison between the phases of excavation. The complimentary potential between the techniques of TLS and automatic photogrammetry was demonstrated by using low altitude aerial images (taken with helium balloon with remotely controlled digital camera) allowing a more comprehensive documentation, in particular in those situations where TLS presents limitations (higher parts of buildings). Interpretation and processing of TLS reflectance images was demonstrated to be a valid tool for the inquiry of the architectural object that allows one to extract relevant information both for Archaeology and Conservation. It was possible to distinguish between several types of joints (even to perceive early interventions done with cement mortars), to detect several constructive patterns through the analysis of the stone cuts, to calculate a vegetation index, and to differentiate between organic and inorganic materials.
ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences
Conservation planning is a complex process involving a wide range of agents such as architects, engineers, conservators and archaeologists. Their integrated inputs contribute to the definition of criteria for the conservation project and the conservation strategy. In this process, graphical documentation is a common denominator to all involved areas-of-expertise. It provides the basis for the dialog between agents coming from different fields of knowledge that often don't speak the same technical language nor share the same codes. The way this dialog can be improved through documentation is the main motivation of our study. In this paper we analyze the requirements of digital documentation in Cultural Heritage (CH) conservation strategies, and we tackle the fundamental role of photogrammetry and terrestrial laser scanning (TLS), and integrated implementation throughout the several steps, from the fieldwork to the conservation planning for CH sites. The described process is demonstrated through the case study of 'the conservation project of the historic walls of Lagos', in south Portugal. After introduction and related work, the study is structured in four main sections. In the second section, we present the case study and conduct an analysis of existing data and preliminary synthesis of heritage values related to the historic walls of Lagos. Second section corresponds to an overview of the project workflow. This spans from recording and documentation, considering geometry, colour, light, materials and degradation forms; to their analysis and diagnosis, resulting in criteria and guidelines for the intervention actions. Third section emphasises on how the simultaneous use of photogrammetry and TLS in the documentation process, and its relationship with other methods and techniques, introduces a distinctive character in the conservation project. Fourth section is about the documentation process with photogrammetry and TLS. Finally, fifth section focus in the analysis and architectural project.
This paper is about a complete photogrammetric record of St. Domingo de Silos' Church (XIV th century), in Alcala la Real (Jaen, Spain). It was declared National Monument in 1931. At present it is a ruin heavily damaged and near to collapse. So, local authorities have decided urgent actions for the reconstruction. Previous to the restoration works, different surveying and photogrammetric techniques were used for a reconstruction project and cataloguing of an important historical building, but at moderate costs with the extensive use of non metric and semi-metric instrumentation. A wide variety of photogrammetric methods and instruments has been applied: analytical and digital plotters; terrestrial metric, semi-metric (reseau plate) and non metric cameras (analogical and digital). Stereoscopic pairs, when possible, were taken with the help of a device which allowed for stereoscopic shots. Convergent photographs were also taken in order to reach a favourable geometry for bundle adjustment (selfcalibration) and control point densification. Both photogrammetric and desktop scanners were used. To maintain low costs, the main final products, in case of planar surfaces, were mosaics of rectified photographs. Cross sections, modelling and structural analysis of deformation of walls and a vault were also made in order to support the final architectural restoration project.
Digital photogrammetry and laser scanning in cultural heritage survey
… of Photogrammetry and …, 2004
A joint project between the Interdept. Research Center of the University of Padova (CIRGEO), a research group of Istituto Tecnico per la Ricerca Scientifica e Tecnologica (IRST) of Trento and the Visual Information Technology group (VIT) of the NRC Canada, ...
Review of Geometric and Radiometric Analyses of Paintings
The Photogrammetric Record, 2011
This paper presents an overview of a number of diagnostic campaigns carried out to assess the conservation state of paintings. The specific characteristics required in cultural heritage applications have been investigated and are reported, where two main fields are considered: radiometric analyses using multispectral images and 3D surveying for geometric deformation analysis by means of photogrammetry and laser scanning. The activities described were accomplished in interdisciplinary teams, composed of photogrammetrists, art-historians, restorers and experts of nondestructive diagnostic techniques.