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Barazzetti L.,Polytechnic of Milan | Remondino F.,3D Optical Metrology Unit | Scaioni M.,Polytechnic of Milan
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives | Year: 2010

Automation in 3D reconstruction involves mainly two tasks: (i) image orientation and (ii) 3D scene reconstruction. Nowadays, automation in (i) can be considered solved for aerial photogrammetric projects, but a general and commercial solution is still pending in case of close-range image blocks. Here, the complexity and diversity of the network geometry make the automatic identification of the image correspondences a challenging task. In this paper we present a methodology to automatically orient a set of targetless close-range images taken with a calibrated camera and the following creation of 3D models with a multi-image matching algorithm. Several real cases, comprehending free-form objects (e.g. bas-relieves, decorations, etc.), building facades and images taken with UAVs are reported and discussed. Lastly, some preliminary results on a methodology for markerless camera calibration are presented. Source

Menna F.,3D Optical Metrology Unit | Nocerino E.,Parthenope University of Naples
Applied Geomatics | Year: 2014

Since 2003, the Barcelona Charter has highlighted the importance of digital recording of historic ships and maritime heritage in general. Although this has been stressed with particular emphasis, three-dimensional (3D) modelling of maritime cultural heritage is still not usual as for archaeology and architecture. 3D modelling in the maritime heritage needs particular requirements. Objects to be recorded range from small replicas in maritime museums up to full-scale vessels still in operation. High geometric accuracy, photorealism of final model and faithful rendering of salient details are usually needed, together with the classical requisites characterising the 3D modelling-from-reality process, i.e., automation, low cost, reliability and flexibility of the modelling technique. In this report, a hybrid multi-technique approach is proposed for maritime heritage preservation, and, as a case study, the 3D modelling of a 3-m-long-scale model of a historic warship, the Indomito, is presented. The survey is placed in a larger project aiming to realize the virtual maritime museum of Parthenope University of Naples, to make it available to the public and also to preserve its cultural heritage. Preliminary results are presented and discussed, highlighting relevant aspects that emerged during the experiment. © Società Italiana di Fotogrammetria e Topografia (SIFET) 2011. Source

Barazzetti L.,Polytechnic of Milan | Remondino F.,3D Optical Metrology Unit | Scaioni M.,Polytechnic of Milan
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives | Year: 2010

The article presents a powerful and automated methodology to extract accurate image correspondences from different kinds of closerange image blocks for their successive orientation with a bundle adjustment. The actual absence of a commercial solution able to automatically orient markerless image blocks confirms the still open research in this field. The developed procedure combines different image processing algorithms and robust estimation methods in order to obtain accurate locations and a uniform distribution of tie points in the images. We demonstrate the capabilities and effectiveness of this method with several tests on closed or open sequences and sparse blocks of images captured by a standard frame (pinhole) camera, but also spherical images. An accuracy evaluation of the achieved 3D object coordinates with photogrammetric bundle techniques is also presented. Source

Manferdini A.M.,University of Bologna | Remondino F.,3D Optical Metrology Unit
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2010

One of the most significant consequences of the introduction of digital 3D modeling in the Cultural Heritage field is the possibility to use 3D models as highly effective and intuitive means of communication as well as interface to share and visualize information collected in databases. Due to the usual complexity of architectural and archaeological artifacts or sites, their digital models need be subdivided in sub-components and organized following semantic definitions in order to facilitate data retrieval. This paper outlines a methodology to semantically segment complex reality-based 3D models, annotate information and share the results within online open-source tools. The segmentation stage to subdivide and organize 3D models is based on both automated and manual methods, giving priority to automated procedures that can ease and speed these steps but not neglecting the user intervention to achieve accurate results. The segmented 3D models are then visualized in web-based systems to allow data access to a wider range of users and enlarge knowledge. The methodology is presented and tested on large and complex reality-based 3D models of architectural and archaeological heritage structures. © 2010 Springer-Verlag Berlin Heidelberg. Source

Poli D.,European Commission - Joint Research Center Ispra | Angiuli E.,European Commission - Joint Research Center Ispra | Remondino F.,3D Optical Metrology Unit
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives | Year: 2010

WorldView-2 (WV-2) is DigitalGlobe's latest very high resolution optical sensor. Launched on October 8, 2009, and fully operational since January 5, 2010, it flies along a sun-synchronous orbit at an altitude of 770km. The sensor is able to acquire panchromatic imagery at 0.46m ground resolution (0.52m at 20° off-nadir) and multispectral images in eight spectral bands at 1.8m resolution. In addition to the four typical multispectral bands (blue, green, red, near infrared), the sensors scans the coastal (400-450nm), yellow (585-625nm), red edge (705-745nm) and near infrared-2 (860-1040nm) bands. Stereo images can be planned thanks to the ability of the sensor to rotate off-nadir up to +/-45°. This paper describes the preliminary analysis on WV-2 carried out at the EU Joint Research Center (JRC) in Ispra (Italy) by the ISFEREA Team of the Institute for the Protection and Security of the Citizen (IPSC), and in collaboration with the Bruno Kessler Foundation (FBK) in Trento (Italy). The purpose of the study is to evaluate the radiometric and geometric properties of the sensor and its potentials for 3D information extraction. The images used for the analysis are a stereopair over North-West Italy, where ISFEREA is establishing a testfield. The radiometry of the images is evaluated through different methods, including the estimation of the noise level (standard deviation of the digital number) in homogeneous and non-homogeneous areas. The images are oriented with RPC-based approach: using some GCP (ground control points), the given Rational Polynomial Coefficients (RPC) are improved with an affine transformation to compensate residual systematic errors. For automatic 3D information assessment, a Digital Surface Model (DSM) is generated with the SAT-PP software package and 3D building models are extracted semi-automatically with the CyberCity-Modeler (CCM) package. The methodology and preliminary results are described and discussed. Source

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