Close-range photogrammetry enables documentation of environment-induced deformation of architectural heritage

Deformation, damage and permanent loss of heritage assets due to various physical and environmental factors has always been a major problem. As the availability of funds for conservation and restoration is limited, the digital documentation of heritage objects and monitoring of environment-induced deformations are increasingly important for cultural heritage preservation. Our study elucidates developments in the digital image capturing and processing for recording architectural heritage objects focusing on the digital camera calibration, close-range imaging, and photogrammetric modelling of complex structures using image matching techniques. A particular consideration in this paper is given to the ortho-photographic image compiling and accuracy assessment procedure. The practicality of the methodology is demonstrated by applying photogrammetric system PhotoMod for documentation of decorative elements in Uzutrakis manor, a national heritage site in Trakai, Lithuania

Surveying and Three-Dimensional Modeling for Preservation and Structural Analysis of Cultural Heritage

Dense point clouds can be used for three important steps in structural analysis, in the field of cultural heritage, regardless of which instrument it was used for acquisition data. Firstly, they allow deriving the geometric part of a finite element (FE) model automatically or semi-automatically. User input is mainly required to complement invisible parts and boundaries of the structure, and to assign meaningful approximate physical parameters. Secondly, FE model obtained from point clouds can be used to estimate better and more precise parameters of the structural analysis, i.e., to train the FE model. Finally, the definition of a correct Level of Detail about the three-dimensional model, deriving from the initial point cloud, can be used to define the limit beyond which the structural analysis is compromised, or anyway less precise. In this work of research, this will be demonstrated using three different case studies of buildings, consisting mainly of masonry, measured through terrestrial laser scanning and photogrammetric acquisitions. This approach is not a typical study for geomatics analysis, but its challenges allow studying benefits and limitations. The results and the proposed approaches could represent a step towards a multidisciplinary approach where Geomatics can play a critical role in the monitoring and civil engineering field. Furthermore, through a geometrical reconstruction, different analyses and comparisons are possible, in order to evaluate how the numerical model is accurate. In fact, the discrepancies between the different results allow to evaluate how, from a geometric and simplified modeling, important details can be lost. This causes, for example, modifications in terms of mass and volume of the structure

Digital photogrammetry for visualisation in architecture and archaeology

Bibliography: leaves 117-125.The task of recording our physical heritage is of significant importance: our past cannot be divorced from the present and it plays an integral part in the shaping of our future. This applies not only to structures that are hundreds of years old, but relatively more recent architectural structures also require adequate documentation if they are to be preserved for future generations. In recording such structures, the traditional 2D methods are proving inadequate. It will be beneficial to conservationists, archaeologists, researchers, historians and students alike if accurate and extensive digital 3D models of archaeological structures can be generated. This thesis investigates a method of creating such models, using digital photogrammetry. Three different types of model were generated: 1. the simple CAD (Computer Aided Design) model; 2. an amalgamation of 3D line drawings; and 3. an accurate surface model of the building using DSMs (Digital Surface Models) and orthophotos

Visual programming for structural assessment of out-of-plane mechanisms in historic masonry structures

This work aims at proposing a novel procedure for the seismic assessment of historic masonry structures which is computationally efficient and does not rely on destructive material tests. Digital datasets describing the geometric configuration of historic masonry structures are employed to automatically generate a non-linear Finite Element (FE) model and investigate on possible collapse modes. A configuration of failure surfaces is therefore detected through the Control Surface Method (CSM), which is here proposed for the first time. In a following step of the analysis, structural macroblocks are identified, whereas an upper bound limit analysis approach is employed to estimate the structural capacity of the structure. Genetic Algorithms are also employed to detect the actual failure mode for the structure. The procedure is implemented into a visual coding environment, which allows one to parametrically explore all possible failure surfaces and immediately visualize the effects of the user assumptions. This is particularly suited to support a decisions-making process which strongly relay on engineering judgement. The procedure is validated by the analysis of two benchmark cases, whose results are presented and discussed

Rock Art Documentation in the Digital Age: The Rafter Z Site (24RB2809) in Rosebud County, Montana

The Rafter Z site was a previously unrecorded rock art site located on private land in Rosebud County, Montana. The resulting thesis provided an opportunity to systematically document the site and conduct important rock art research within southeastern Montana. The thesis project was sectioned into two phases. The first phase provided the documentation of the Rafter Z site, surveying of 170-acres of private land, documentation of three additional cultural sites, and a comprehensive analysis of the Rafter Z site. This research showed that the Rafter Z site constitutes one of the larger rock art sites in Rosebud County and the greater southeastern Montana region. Housing 36 shield-bearing warriors and 14 freestanding shields, the site offers a unique perspective into the Plains warrior ethos from the Late Prehistoric period. In addition, the site provides insight into early Crow and the Kiowa/ Kiowa Apache use of the region during the mid-to-late Prehistoric period with its mixture of Castle Garden and Timber Creek style rock art figures. The second phase of the proposed project utilized two digital techniques recently applied to rock art documentation: photogrammetry and reflectance transformation imaging (RTI). Several variables were tested to ascertain the best methods to effectively render 3D models using photogrammetry and conduct RTI on the sandstone substrate. Overall, these digital documentation methods heightened the interpretive and archival quality of the site documentation and data collected. Enhancing the archival quality of rock art will allow future research to occur when access may be limited