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Victor M . Ferreira
Assistant Professor in the Department of Drawing, Geometry and Computation, of the Lisbon School of Architecture, University of Lisbon (www.fa.ulisboa.pt).
He teaches CAD, 3D Modelling, Image Editing, Digital Publishing (both Web and DTP), web design (Html/CSS), and Digital 3d Surveying of built environment to students of Architecture, Urban Planning and Design.
PHD in Regional and Urban Planning (IST.UTL).
Researcher in CIAUD (FAUL), in the ArcHC3D group (http://archc3d.fa.ulisboa.pt), working with laser scanning, Multiview Photogrammetry (Sfm), and 3D survey and modelling of Heritage and Urban areas.
Phone: +351213615000 ext. 5832
Address: Rua Sá Nogueira
Polo Universitário do Alto da Ajuda
1349-055 Lisboa
Portugal
He teaches CAD, 3D Modelling, Image Editing, Digital Publishing (both Web and DTP), web design (Html/CSS), and Digital 3d Surveying of built environment to students of Architecture, Urban Planning and Design.
PHD in Regional and Urban Planning (IST.UTL).
Researcher in CIAUD (FAUL), in the ArcHC3D group (http://archc3d.fa.ulisboa.pt), working with laser scanning, Multiview Photogrammetry (Sfm), and 3D survey and modelling of Heritage and Urban areas.
Phone: +351213615000 ext. 5832
Address: Rua Sá Nogueira
Polo Universitário do Alto da Ajuda
1349-055 Lisboa
Portugal
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scanning have been frequently considered valuable tools for
creating three-dimensional models from which metric and
radiometric information can be derived for the survey of cultural heritage buildings, reverse engineering, space exploration and other areas. However reconstructing old heritage buildings digitally may be a challenging task especially when the shape, geometry and volume of these buildings are intrinsically complex therefore requiring specific methods or ad-hoc solutions. Medieval castles are typical constructions that exhibit these kinds of features with inaccessible locations, bridges, wide areas followed by small and limited spaces, battlements, towers and walls occluded by vegetation. This variety of problems can prolong the time required to complete the tasks when using laser scanning or photogrammetry with conventional lenses. In this paper we present a research of use of fisheye lenses in photogrammetry, for capturing medieval castles’ geometric and radiometric information of hard to reach places. We conclude that this reduces the total time needed to capture the same amount of information gathered with other instruments, it allows replacing the usage of Unmanned Aerial Vehicles (UAV) in low flight situations, makes the survey connection between areas of a building easier, reduces the total number of images and allows making a general fast survey. The castles illustrated in this paper are the Castle of Sesimbra and the Castle of The Convent of Christ, both in Portugal.
We start by describing the theoretical and instrumental frameworks proposed. Then we describe and discuss a set of two exercises developed during one semester, giving examples of the work produced by the students. Finally we end with some considerations to be taken into account in future editions of the course.
After we describe the algorithm developed to dissipate the closure error. Finally we present an application of the algorithm and a comparison with an automatic procedure, describing the pros and cons of the adoption of the developed algorithm.
The paper describes the use of Terrestrial Laser Scanning (TLS) techniques to acquire information on the São Vicente de Fora church, then the use of such information to develop the corresponding shape grammar, and finally the comparison of this grammar with the grammar of Alberti’s treatise, to determine the grammatical transformations that occurred between the two grammars.
Mathematica allowed us to visualize the interpolations surface of the points sample and obtain an approximation of the surface reconstruction.
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.
Através de aplicações ao Convento de Cristo, discute-se o contributo que a documentação gráfica produzida através da fotogrametria automática, sob a metodologia SFM/MVS (structure-from-motion / multi-view-stereo), e do varrimento laser 3D, pode dar para a melhoria dos processos de registo do património arquitectónico, dando origem a uma documentação base mais fiel ao objecto, e por isso potenciadora dos processos de interpretação e análise a efectuar pelos agentes da Conservação.
scanning have been frequently considered valuable tools for
creating three-dimensional models from which metric and
radiometric information can be derived for the survey of cultural heritage buildings, reverse engineering, space exploration and other areas. However reconstructing old heritage buildings digitally may be a challenging task especially when the shape, geometry and volume of these buildings are intrinsically complex therefore requiring specific methods or ad-hoc solutions. Medieval castles are typical constructions that exhibit these kinds of features with inaccessible locations, bridges, wide areas followed by small and limited spaces, battlements, towers and walls occluded by vegetation. This variety of problems can prolong the time required to complete the tasks when using laser scanning or photogrammetry with conventional lenses. In this paper we present a research of use of fisheye lenses in photogrammetry, for capturing medieval castles’ geometric and radiometric information of hard to reach places. We conclude that this reduces the total time needed to capture the same amount of information gathered with other instruments, it allows replacing the usage of Unmanned Aerial Vehicles (UAV) in low flight situations, makes the survey connection between areas of a building easier, reduces the total number of images and allows making a general fast survey. The castles illustrated in this paper are the Castle of Sesimbra and the Castle of The Convent of Christ, both in Portugal.
We start by describing the theoretical and instrumental frameworks proposed. Then we describe and discuss a set of two exercises developed during one semester, giving examples of the work produced by the students. Finally we end with some considerations to be taken into account in future editions of the course.
After we describe the algorithm developed to dissipate the closure error. Finally we present an application of the algorithm and a comparison with an automatic procedure, describing the pros and cons of the adoption of the developed algorithm.
The paper describes the use of Terrestrial Laser Scanning (TLS) techniques to acquire information on the São Vicente de Fora church, then the use of such information to develop the corresponding shape grammar, and finally the comparison of this grammar with the grammar of Alberti’s treatise, to determine the grammatical transformations that occurred between the two grammars.
Mathematica allowed us to visualize the interpolations surface of the points sample and obtain an approximation of the surface reconstruction.
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.
Através de aplicações ao Convento de Cristo, discute-se o contributo que a documentação gráfica produzida através da fotogrametria automática, sob a metodologia SFM/MVS (structure-from-motion / multi-view-stereo), e do varrimento laser 3D, pode dar para a melhoria dos processos de registo do património arquitectónico, dando origem a uma documentação base mais fiel ao objecto, e por isso potenciadora dos processos de interpretação e análise a efectuar pelos agentes da Conservação.