Search results for "Close range"
showing 7 items of 17 documents
Close-Range Photogrammetric Tools for Epigraphic Surveys
2016
In this article, we present a method to carry out a computerized epigraphic survey of historic stones and their engraved epigraphy. In fact, the preservation of archaeological objects has always been an issue of concern for the research community. On the one hand, the fragility of the objects limits their study. On the other hand, such objects are housed in museums, libraries, and institutions worldwide, locations that significantly limit their accessibility. Different survey methods have been carried out in these attempts to overcome the aforementioned limitations. Among them, the MicMac open source software was used in this work to survey and process the dense correlation of the hieroglyp…
Bed Topography Reconstruction in a Large Amplitude Meandering Flume: Application of Close Range Photogrammetry
2014
Natural rivers are characterized by continuous variations in bed topography, especially along curved reaches. High resolution topographic data are necessary to analyze the mutual interactions between the downstream flow and the cross-stream flow, which determine the distribution of the bed-shear stress along the channel. Because of the difficulty in acquiring good and accurate data in rivers, the major part of studies have been conducted in laboratory flumes. This paper reports on a laboratory study in which the automatic digital photogrammetric survey was applied to derive the high-resolution Digital Surface Model (DSM) of the bed topography in a large amplitude meandering flume. In order …
Asserting the Precise Position of 3D and Multispectral Acquisition Systems for Multisensor Registration Applied to Cultural Heritage Analysis
2012
International audience; We present a novel method to register multispectral acquisitions on a 3D model. The method is based on the external tracking of the acquisition systems using close-range photogrammetric techniques: multiple calibrated cameras simultaneously observe the successive acquisition systems in use. The views from these cameras are used to precisely determine the position of each acquisition system. All datasets can then be projected in the same coordinate system. The registration is thus independent from the quality and content of the data. This method is well suited to the study of cultural heritage or any other application where we do not wish to place targets on the objec…
Close range photogrammetry for measurement of paintings surface deformation
2009
The paper describes the first results about a study on the measurement of paintings surface deformation. The study was carried out using one ancient painting model made in a restoration laboratory and consolidated with the materials and dilutions most frequently used in the field of conservation. The restorers suppose deformations of the paintings surface from 0.1 mm to some millimetre when the painting model is keeping in environment with the presence of humidity and temperature fluctuations. The main purpose of the study is to evaluate the relative accuracy and the reliability of multi-images photogrammetric techniques related to the camera stations network and to the commercial software …
Control of structural problems in cultural heritage monuments using close-range photogrammetry and computer methods
2005
This paper deals with the conservation of monumental buildings. Several methods used for the architectonic documentation are analysed in this study. Computers methods and close-range photogrammetry are proposed as a preventive method which allows to detect, measure and track the temporal evolution of some structural problems detected, and also to assess the degree of conservation of the materials employed. A group of monuments belonging to the Spanish historical heritage is analysed. In order to carry out the analysis a wire-frame model and a photo-realistic textured model were made. Work focused later on the area where structural problems were more acute.
Terrestrial laser scanning and close range photogrammetry for 3D archaeological documentation: the Upper Palaeolithic Cave of Parpalló as a case study
2010
Graphic and metric archaeological documentation is an activity that requires the capture of information from different sources, accurate processing and comprehensive analysis. If monitoring of the state of conservation is required, this task has to be performed before intervention, during and after the completion of the works in a repetitive way. This paper presents the use of terrestrial laser scanning (TLS) in order to effectively produce, prior to intervention, accurate and high-resolution 3D models of a cave with engravings dating back to the Upper Palaeolithic era. The processing of the TLS data is discussed in detail in order to create digital surface models. The complexity of the cav…
A NEW PHOTOGRAMMETRIC LAYOUT OF CAMERA STATIONS: A CASE STUDY
2015
This paper describes an easy and low cost photogrammetric method to determine the height of a point in relation to a reference plane. Such a method consists of an innovative geometric layout of the camera stations and specific algorithms. It is applicable to architectural surveying, in particular when the surface to be surveyed present a definitive geometry, with clearly identifiable defined points. The effectiveness of this method was verified through a case study carried out with the use of a digital camera and three dimensional targets. Two different pairs of images were obtained. One pair consists of images taken with a 35 mm and 19 mm focal length; the other one consists of images take…