640 research outputs found
R-CAUSTIC: Rippling CAUSTICs underwater Image dataset
No full text<p> </p>
<h3><strong>Version 2 available! Please make sure to download the latest version of the dataset! <br></strong></h3>
<p> </p>
<p><strong>Description</strong></p>
<p>Rippling caustics seem to be the main factor degrading the underwater RGB image quality and affecting the image- based 3D reconstruction process in very shallow waters. These effects are adversely affecting image matching algorithms by throwing off most of them, leading to less accurate matches and causing issues in the Simultaneous Localization and Mapping (SLAM) based navigation of the Remotely Operated Vehicles (ROV) and Autonomous Underwater Vehicles (AUV) on shallow waters. Also, they are the main cause for dissimilarities in the generated textures and orthoimages. In order to fill the gap in the literature regading underwater rippling caustics imagery with real ground truth and reference images, the first real-world underwater caustics benchmark dataset which contains 1465 underwater images is presented. Together with the RGB imagery, the corresponding generated ground truth images are delivered for facilitating the training and testing of machine learning and deep learning methods for image classification. R-CAUSTIC dataset also provides the necessary data to evaluate, at least to some extent, the performance of 3D reconstruction approaches. Data were acquired using a GoPro Hero 4 Black action camera with image dimensions of 4000 x 3000 pixels, focal length of 2.77mm and pixel size of 1.55μm and a tripod. Action cameras are widely used for underwater image acquisition. The dataset was captured in near-shore underwater sites at depths varying from 0.5 to 2m. No artificial light sources were used. Due to the wind, the turbulent surface of the water created dynamic rippling caustics on the seabed. In total 1465 RGB images were collected, separated in 7 different datasets; five of them containing stereo images, one of them tri-stereo images and one consists of multi-stereo imagery acquired in 7 different camera poses.</p>
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<p><strong>Publication</strong></p>
<p>The paper is availbale in Open Access here: https://ieeexplore.ieee.org/document/10172291</p>
<p><strong>If you use this dataset please cite it as R-CAUSTIC</strong> [Reference].<br>[Reference]: <strong>P. Agrafiotis, K. Karantzalos and A. Georgopoulos, "Seafloor-Invariant Caustics Removal From Underwater Imagery," in </strong><em><strong>IEEE Journal of Oceanic Engineering</strong></em><strong>, vol. 48, no. 4, pp. 1300-1321, Oct. 2023, doi: 10.1109/JOE.2023.3277168.</strong></p>
<p>BibTeX:</p>
<p>@ARTICLE{10172291, author={Agrafiotis, Panagiotis and Karantzalos, Konstantinos and Georgopoulos, Andreas}, journal={IEEE Journal of Oceanic Engineering}, title={Seafloor-Invariant Caustics Removal From Underwater Imagery}, year={2023}, volume={48}, number={4}, pages={1300-1321}, doi={10.1109/JOE.2023.3277168}}</p>
<p> </p>
R-CAUSTIC: Rippling CAUSTICs underwater Image dataset
No full text<p><strong>Description</strong></p><p>Rippling caustics seem to be the main factor degrading the underwater RGB image quality and affecting the image- based 3D reconstruction process in very shallow waters. These effects are adversely affecting image matching algorithms by throwing off most of them, leading to less accurate matches and causing issues in the Simultaneous Localization and Mapping (SLAM) based navigation of the Remotely Operated Vehicles (ROV) and Autonomous Underwater Vehicles (AUV) on shallow waters. Also, they are the main cause for dissimilarities in the generated textures and orthoimages. In order to fill the gap in the literature regading underwater rippling caustics imagery with real ground truth and reference images, the first real-world underwater caustics benchmark dataset which contains 1465 underwater images is presented. Together with the RGB imagery, the corresponding generated ground truth images are delivered for facilitating the training and testing of machine learning and deep learning methods for image classification. R-CAUSTIC dataset also provides the necessary data to evaluate, at least to some extent, the performance of 3D reconstruction approaches. Data were acquired using a GoPro Hero 4 Black action camera with image dimensions of 4000 x 3000 pixels, focal length of 2.77mm and pixel size of 1.55μm and a tripod. Action cameras are widely used for underwater image acquisition. The dataset was captured in near-shore underwater sites at depths varying from 0.5 to 2m. No artificial light sources were used. Due to the wind, the turbulent surface of the water created dynamic rippling caustics on the seabed. In total 1465 RGB images were collected, separated in 7 different datasets; five of them containing stereo images, one of them tri-stereo images and one consists of multi-stereo imagery acquired in 7 different camera poses.</p><p> </p><p><strong>Publication</strong></p><p>The paper is availbale in Open Access here: https://ieeexplore.ieee.org/document/10172291</p><p><strong>If you use this dataset please cite it as R-CAUSTIC</strong> [Reference].<br>[Reference]: <strong>P. Agrafiotis, K. Karantzalos and A. Georgopoulos, "Seafloor-Invariant Caustics Removal From Underwater Imagery," in </strong><i><strong>IEEE Journal of Oceanic Engineering</strong></i><strong>, vol. 48, no. 4, pp. 1300-1321, Oct. 2023, doi: 10.1109/JOE.2023.3277168.</strong></p><p>BibTeX:</p><p>@ARTICLE{10172291,
author={Agrafiotis, Panagiotis and Karantzalos, Konstantinos and Georgopoulos, Andreas},
journal={IEEE Journal of Oceanic Engineering},
title={Seafloor-Invariant Caustics Removal From Underwater Imagery},
year={2023},
volume={48},
number={4},
pages={1300-1321},
doi={10.1109/JOE.2023.3277168}}</p><p> </p>
BIM Application for the Basilica of San Marco in Venice: Procedures and Methodologies for the Study of Complex Architectures
No full textThe BIM (Building Information Model) of the Basilica of San Marco contains the solutions to the many problems encountered during its acquisition and modelling stage. The complexity of the church and the variety of its materials (golden mosaics, capitals of different styles and origins, statues and decorations in many different marble types), the large and continuous stream of visitors, and the request for high-resolution models and orthophotos forced us to devise a strategy for the digitization process: a multiscale photogrammetric approach allowed us to acquire all materials and decorations of the basilica and, according to the use of a reference topographic network, we could split the whole work into smaller parts. Later, in the modelling stage, the decision to use a non-commercial BIM software allowed us to use NURBS (non-uniform rational B-spline) for a more accurate restitution of architectural elements and decorations and to integrate high-resolution orthophotos for the description of all surfaces (both marbles and golden mosaics). The established workflow started with the initial acquisition of images and resulted in both final models and high-quality orthophotos, so we were able to obtain different outcomes to answer the specific needs of the church, its managers, and its users
Environmental ethics: values in and duties to the natural world (summarized with commentary by Panagiotis Perros)
No full textSummarized with commentary in Greek by Panagiotis Perros.Environmental ethics stands on a frontier, as radically theoretical as it is applied. Alone, it asks whether there can be nonhuman objects of duty. Animals, plants, endangered species, ecosystems, and even Earth are progressively unfamiliar as objects of duty, and puzzles arise both for theory and practice. Answers to such questions are as urgent as any humans face, and intimately related to the four principal issues on the world agenda: peace, population, development, and environment
State of the art and applications in archaeological underwater 3D recording and mapping
No full textSince remote times, mankind has been bound to water bodies and evidence of human life from the very beginning hides under the water level, off the coasts, under shallow seas or deep oceans, but also inland water bodies of countries all around the world. Recording, documenting and, ultimately, protecting underwater cultural heritage is an obligation of mankind and dictated by international treaties like the Convention on the Protection of the Underwater Cultural Heritage that fosters and encourages the use of “non-destructive techniques and survey methods in preference over the recovery of objects”. 3D digital surveying and mapping techniques represent an invaluable set of effective tools for reconnaissance, documentation, monitoring, but also public diffusion and awareness of underwater cultural heritage (UCH) assets. This paper presents an extensive review over the sensors and the methodologies used in archaeological underwater 3D recording and mapping together with relevant highlights of well renowned projects in 3D recording underwater
Photogrammetric Tools for Restoration Purposes: Open-Air Bronze Surfaces of Sculptures
No full textThe restoration of an outdoor bronze artefact, among the various processes, provides the cleaning activity, a delicate task that requires a work of synthesis to define - checking step by step its peculiar irreversible process - an effective operating protocol on a limited patch area to be extended to the entire artwork's surface. The paper presents a user-friendly, semi-automated 3D photogrammetry-based solution, developed and validated during the ongoing restoration of the Neptune Fountain in Bologna, able to support restorers in the open-air bronze artwork cleaning from corrosion and weathering decay. The purpose of the developed solution has been to offer an operative and useful support tool for restorers, throughout the restoration work, to ascertain the 'surfaces' to be cleaned, for testing and gathering information (as direct feedback) of the reached results. The proposed solution, in fact, thanks to a customized interface and using an OpenGL viewer, can reproduce with a high level of fidelity in colour and shape the bronze surface before, during and after the clear-out treatment
CAMERA CONSTANT IN THE CASE OF TWO MEDIA PHOTOGRAMMETRY
No full textRefraction is the main cause of geometric distortions in the case of two media photogrammetry. However, this effect cannot be compensated and corrected by a suitable camera calibration procedure (Georgopoulos and Agrafiotis, 2012). In addition, according to the literature (Lavest et al. 2000), when the camera is underwater, the effective focal length is approximately equal to that in the air multiplied by the refractive index of water. This ratio depends on the composition of the water (salinity, temperature, etc.) and usually ranges from 1.10 to 1.34. It seems, that in two media photogrammetry, the 1.33 factor used for clean water in underwater cases does not apply and the most probable relation of the effective camera constant to the one in air is depending of the percentages of air and water within the total camera-to-object distance. This paper examines this relation in detail, verifies it and develops it through the application of calibration methods using different test fields. In addition the current methodologies for underwater and two-media calibration are mentioned and the problem of two-media calibration is described and analysed
Does genetic diversity on corporate boards lead to improved environmental performance?
No full textElsevier
Journal of International Financial Markets, Institutions and Money
Volume 84, April 2023, 101756
Journal of International Financial Markets, Institutions and Money
Does genetic diversity on corporate boards lead to improved environmental performance?
Author links open overlay panelRenatas Kizys a, Emmanuel C. Mamatzakis b, Panagiotis Tzouvanas c
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https://doi.org/10.1016/j.intfin.2023.101756
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Highlights
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We examine the effect of boards’ genetic diversity (GENETICD) on corporate ESG performance.
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ESG performance and disclosures are higher in more genetically diverse firms.
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The positive GENETICD effect on ESG performance is driven by the environmental pillar.
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Corporate carbon performance significantly improves with increases in GENETICD.
We study the effects of boards’ genetic diversity on corporate environmental performance. Using a multidimensional information set for 3690 US firms during the period from 2005 to 2019, and three different measures of genetic diversity, we find that, pursuant to the diversity theory, which posits that diversity improves the quality of management decisions and business ethics, genetic diversity leads to improved environmental performance. We also find that genetic diversity improves carbon and governance performance, and ESG disclosure. Particularly, a one percentage point increase in boards’ genetic diversity will increase the carbon performance, measured by the inverse of the carbon emissions to total assets ratio, and environmental performance by 3.54% and 5.57%, respectively. Our results remain robust to different model specifications, while also controlling for endogeneity. In terms of policy implications, results suggest that the key to tackling climate challenges is to promote boards’ genetic diversity
Theoretical and Practical Survey of Backhaul Connectivity Options
No full textThe aim of the Portable Wireless LAN trial programme by JANET, under which this work is being carried out, is twofold. Firstly, we needed to develop a portable and easily carried Wireless LAN (WLAN) kit that should be able to provide local and global connectivity to the devices individuals carry for an academic study or module outdoors. In simple terms, the portable WLAN kit should provide local connectivity to devices around it, in the form of a 802.11b/g wireless network, and global connectivity with the aid of a backhaul connectivity option, such as a Satellite, 3G/UMTS or WiMAX link or by establishing its own connection to the Internet if that is feasible. Secondly, the project needed to study the backhaul connectivity options that could be utilized in the above context, so that we could identify and evaluate the suitability and applicability of the backhaul connectivity options that the Portable WLAN kit could utilize to establish a connection over. This report fulfills the second aim of the project and studies theoretically and practically three possible backhaul connectivity options, namely Cellular networks, Satellite Communications and WiMAX network, in an effort to give an insight of their characteristics and applicability for the goal of this project
Dataset in support of the Southampton doctoral thesis 'The boatbuilding tradition of the Aegean during the Late Neolithic – Early Bronze Age periods. Typological classification, digital reconstruction and seakeeping assessment'
No full textDataset in support of the Southampton doctoral thesis 'The boatbuilding tradition of the Aegean during the Late Neolithic – Early Bronze Age periods. Typological classification, digital reconstruction and seakeeping assessment' Appendix D - Resistance data and Appendix C - Stability data.
This dataset is focused on two appendices:
Appendix D - Resistance data. D.1 Resistance data produced by the author via MAXSURF Resistance for this thesis.
Appendix C - Stability data
C1. Stability data – STIX and ISO criteria, produced by the author via MAXSURF Stability software for his thesis
This research was funded by Southampton Marine and Maritime Institute (SMMI), Vice-Chancellor's Scholarship, Greek Archaeological Committee UK (GACUK)
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