scholarly journals Multifaceted Geometric Assessment towards Simplified Urban Surfaces Built by 3D Reconstruction

2019 ◽  
Vol 8 (8) ◽  
pp. 360
Author(s):  
Sheng’en Liu ◽  
Hui Yi ◽  
Xiangning Chen ◽  
Decheng Wang ◽  
Wei Jin
Keyword(s):  
3D Reconstruction ◽  
Urban Areas ◽  
Large Scale ◽  
Smart Cities ◽  
Three Dimensional ◽  
Research Fields ◽  
Planar Surfaces ◽  
Surface Simplification ◽  
Significant Step ◽  
Almost All

Large-scale three-dimensional (3D) reconstruction from multi-view images is used to generate 3D mesh surfaces, which are usually built for urban areas and are widely applied in many research hotspots, such as smart cities. Their simplification is a significant step for 3D roaming, pattern recognition, and other research fields. The simplification quality has been assessed in several studies. On the one hand, almost all studies on surface simplification have measured simplification errors using the surface comparison tool Metro, which does not preserve sufficient detail. On the other hand, the reconstruction precision of urban surfaces varies as a result of homogeneity or heterogeneity. Therefore, it is difficult to assess simplification quality without surface classification. These difficulties are addressed in this study by first classifying urban surfaces into planar surfaces, detailed surfaces, and urban frameworks according to the simplification errors of different types of surfaces and then measuring these errors after sampling. A series of assessment indexes are also provided to contribute to the advancement of simplification algorithms.

scholarly journals 3D Reconstruction of Cultural Heritage Sites as an Educational Approach. The Sanctuary of Delphi

2021 ◽  
Vol 11 (8) ◽  
pp. 3635
Author(s):  
Ioannis Liritzis ◽  
Pantelis Volonakis ◽  
Spyros Vosinakis
Keyword(s):  
University Students ◽  
3D Reconstruction ◽  
Cultural Heritage ◽  
New Technology ◽  
Three Dimensional ◽  
Computer Gaming ◽  
Educational Approach ◽  
Heritage Sites ◽  
3D Environment ◽  
Almost All

In the field of cultural heritage, three-dimensional (3D) reconstruction of monuments is a usual activity for many professionals. The aim in this paper focuses on the new technology educational application combining science, history, and archaeology. Being involved in almost all stages of implementation steps and assessing the level of participation, university students use tools of computer gaming platform and participate in ways of planning the virtual environment which improves their education through e-Learning. The virtual 3D environment is made with different imaging methods (helium-filled balloon, Structure for motion, 3D repository models) and a developmental plan has been designed for use in many future applications. Digital tools were used with 3D reconstructed buildings from the museum archive to Unity 3D for the design. The pilot study of Information Technology work has been employed to introduce cultural heritage and archaeology to university syllabuses. It included students with a questionnaire which has been evaluated accordingly. As a result, the university students were inspired to immerse themselves into the virtual lab, aiming to increasing the level of interaction. The results show a satisfactory learning outcome by an easy to use and real 3D environment, a step forward to fill in needs of contemporary online sustainable learning demands.

scholarly journals Intact Planar Abstraction of Buildings via Global Normal Refinement from Noisy Oblique Photogrammetric Point Clouds

2018 ◽  
Vol 7 (11) ◽  
pp. 431 ◽  
Author(s):  
Qing Zhu ◽  
Feng Wang ◽  
Han Hu ◽  
Yulin Ding ◽  
Jiali Xie ◽  
...  
Keyword(s):  
Global Optimization ◽  
Three Dimensional ◽  
Region Growing ◽  
Point Clouds ◽  
Spatial Relations ◽  
Global Scale ◽  
Surface Boundary ◽  
Planar Surfaces ◽  
Normal Vectors ◽  
Almost All

Oblique photogrammetric point clouds are currently one of the major data sources for the three-dimensional level-of-detail reconstruction of buildings. However, they are severely noise-laden and pose serious problems for the effective and automatic surface extraction of buildings. In addition, conventional methods generally use normal vectors estimated in a local neighborhood, which are liable to be affected by noise, leading to inferior results in successive building reconstruction. In this paper, we propose an intact planar abstraction method for buildings, which explicitly handles noise by integrating information in a larger context through global optimization. The information propagates hierarchically from a local to global scale through the following steps: first, based on voxel cloud connectivity segmentation, single points are clustered into supervoxels that are enforced to not cross the surface boundary; second, each supervoxel is expanded to nearby supervoxels through the maximal support region, which strictly enforces planarity; third, the relationships established by the maximal support regions are injected into a global optimization, which reorients the local normal vectors to be more consistent in a larger context; finally, the intact planar surfaces are obtained by region growing using robust normal and point connectivity in the established spatial relations. Experiments on the photogrammetric point clouds obtained from oblique images showed that the proposed method is effective in reducing the influence of noise and retrieving almost all of the major planar structures of the examined buildings.

scholarly journals CitySpeed: A Crowdsensing-Based Integrated Platform for General-Purpose Monitoring of Vehicular Speeds in Smart Cities

Smart Cities ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 46-65 ◽  
Author(s):  
Daniel Costa ◽  
Adson Damasceno ◽  
Ivanovitch Silva
Keyword(s):  
Smart City ◽  
Urban Areas ◽  
Large Scale ◽  
Smart Cities ◽  
General Purpose ◽  
Software Application ◽  
Management Actions ◽  
Modern Cities ◽  
Time Period ◽  
Search Filters

The development of crowdsensing-based technologies has allowed for the use of smartphones in large-scale data collection for different scopes of applications, mostly in a transparent and ubiquitous way. When concerning urban areas and smart city initiatives, the collection and further analysis of information about the highest number of vehicles is of paramount importance, potentially supporting more efficient mobility planning and management actions in modern cities. In this context, this article proposes a public general-purpose platform for acquisition and visualization of vehicular speeds, which can then be exploited by any additional application. For that, a crowdsensing-based mobile software application was developed to collect instantaneous speeds provided by smartphone GPS, formatting and distributing this information to a database system. Such historical data can then be exported or visualized through a web-based comprehensive interface, which provides valuable data when planning traffic mobility in cities; for example, indicating areas with heavier traffic over a certain time period. Therefore, allowing the use of many different search filters and supporting data delivery in the JSON format, the CitySpeed platform can provide services not supported by popular applications, such as Waze and Google Maps, and potentially assist smart city initiatives in this area.

scholarly journals A VOXEL-BASED METADATA STRUCTURE FOR CHANGE DETECTION IN POINT CLOUDS OF LARGE-SCALE URBAN AREAS

2018 ◽  
Vol IV-2 ◽  
pp. 97-104
Author(s):  
J. Gehrung ◽  
M. Hebel ◽  
M. Arens ◽  
U. Stilla
Keyword(s):  
Change Detection ◽  
Urban Areas ◽  
Laser Scanning ◽  
Large Scale ◽  
Point Clouds ◽  
Urban Environments ◽  
Detection Methods ◽  
Planar Surfaces ◽  
Occupancy Grids ◽  
Speed Up

Mobile laser scanning has not only the potential to create detailed representations of urban environments, but also to determine changes up to a very detailed level. An environment representation for change detection in large scale urban environments based on point clouds has drawbacks in terms of memory scalability. Volumes, however, are a promising building block for memory efficient change detection methods. The challenge of working with 3D occupancy grids is that the usual raycasting-based methods applied for their generation lead to artifacts caused by the traversal of unfavorable discretized space. These artifacts have the potential to distort the state of voxels in close proximity to planar structures. In this work we propose a raycasting approach that utilizes knowledge about planar surfaces to completely prevent this kind of artifacts. To demonstrate the capabilities of our approach, a method for the iterative volumetric approximation of point clouds that allows to speed up the raycasting by 36 percent is proposed.

Combining dynamic city sensors to build a three-dimensional thermal environment cloud information system for smart cities

Impact ◽  
2020 ◽  
Vol 2020 (6) ◽  
pp. 26-28
Author(s):  
Kochiu Wu
Keyword(s):  
Information System ◽  
Urban Areas ◽  
Chinese Culture ◽  
Energy Savings ◽  
Thermal Environment ◽  
Smart Cities ◽  
Three Dimensional ◽  
Policy Makers ◽  
University Of Technology ◽  
New Information

Professors Ko-Chiu Wu, Chih-Hong Huang and Hsiao-Tung Chang from the National Taipei University of Technology and Chinese Culture University are combining dynamic city sensors to build a 3D thermal environment cloud information system for smart cities. They seek to uncover new information about urban heat island (UHI) by describing the dynamic phenomena underway. The ultimate aim of this study is to survey the thermal environment data in the horizontal and vertical interspace of urban areas. The data and insight the team gathers will be extremely useful to policy makers and city planners, as well as designing urban spaces with the comfort of citizens in mind, it is hoped they will be able to mitigate the effects of UHI and even make energy savings using the 3D maps.

Crowdsensing in Smart Cities

2019 ◽  
pp. 893-915
Author(s):  
Paolo Bellavista ◽  
Giuseppe Cardone ◽  
Antonio Corradi ◽  
Luca Foschini ◽  
Raffaele Ianniello
Keyword(s):  
Urban Areas ◽  
Large Scale ◽  
Smart Cities ◽  
Design Guidelines ◽  
Technical Data ◽  
Fine Grained ◽  
Living Lab ◽  
Widespread Availability ◽  
One Year ◽  
The University

The widespread availability of smartphones with on-board sensors has recently enabled the possibility of harvesting large quantities of monitoring data in urban areas, thus enabling so-called crowdsensing solutions, which make it possible to achieve very large-scale and fine-grained sensing by exploiting all personal resources and mobile activities in Smart Cities. In fact, the information gathered from people, systems, and things, including both social and technical data, is one of the most valuable resources available to a city's stakeholders, but its huge volume makes its integration and processing, especially in a real-time and scalable manner, very difficult. This chapter presents and discusses currently available crowdsensing and participatory solutions. After presenting the current state-of-the-art crowdsensing management infrastructures, by carefully considering the related and primary design guidelines/choices and implementation issues/opportunities, it provides an in-depth presentation of the related work in the field. Moreover, it presents some novel experimental results collected in the ParticipAct Crowdsensing Living Lab testbed, an ongoing experiment at the University of Bologna that involves 150 students for one year in a very large-scale crowdsensing campaign.

Crowdsensing in Smart Cities

2015 ◽  
pp. 316-338 ◽  
Author(s):  
Paolo Bellavista ◽  
Giuseppe Cardone ◽  
Antonio Corradi ◽  
Luca Foschini ◽  
Raffaele Ianniello
Keyword(s):  
Urban Areas ◽  
Large Scale ◽  
Smart Cities ◽  
Design Guidelines ◽  
Technical Data ◽  
Fine Grained ◽  
Living Lab ◽  
Widespread Availability ◽  
One Year ◽  
The University

The widespread availability of smartphones with on-board sensors has recently enabled the possibility of harvesting large quantities of monitoring data in urban areas, thus enabling so-called crowdsensing solutions, which make it possible to achieve very large-scale and fine-grained sensing by exploiting all personal resources and mobile activities in Smart Cities. In fact, the information gathered from people, systems, and things, including both social and technical data, is one of the most valuable resources available to a city's stakeholders, but its huge volume makes its integration and processing, especially in a real-time and scalable manner, very difficult. This chapter presents and discusses currently available crowdsensing and participatory solutions. After presenting the current state-of-the-art crowdsensing management infrastructures, by carefully considering the related and primary design guidelines/choices and implementation issues/opportunities, it provides an in-depth presentation of the related work in the field. Moreover, it presents some novel experimental results collected in the ParticipAct Crowdsensing Living Lab testbed, an ongoing experiment at the University of Bologna that involves 150 students for one year in a very large-scale crowdsensing campaign.

ANALYSIS AND SIMULATION OF LONG-RANGE CORRELATIONS IN CURVED SPACE

2009 ◽  
Vol 20 (08) ◽  
pp. 1211-1232 ◽  
Author(s):  
ALI REZA MEHRABI ◽  
MUHAMMAD SAHIMI
Keyword(s):  
Long Range ◽  
Large Scale ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Amorphous Semiconductors ◽  
Curved Space ◽  
Long Range Correlations ◽  
Planar Surfaces ◽  
Positively Curved ◽  
Industrial Problem

Numerical simulation and analysis of long-range correlations in curved space are studied. The study is motivated by the problem of constructing accurate models of large-scale porous media which usually contain long-range correlations in their various properties (such as their permeability, porosity, and elastic moduli) within and between their strata that are typically curved layers. The problem is, however, relevant to many other important models and phenomena in which extended correlations in curved space play a prominent role. Examples include the nonlinear σ-model in a curved space, models for describing the long-range structural correlations of amorphous semiconductors that consist of polytopes (tilings of positively-curved three-dimensional space), long-range correlations in the extrapolar total zone, and models in which the Universe is created by bubble nucleations and contain long-range correlations in the fluctuations in the curved spacetime. The study is also relevant to the important industrial problem of designing highly curved objects, such as cars and ships, which use composite materials that contain extended correlations in their property values. We study such correlations along two- and three-dimensional curves, as well as curved surfaces. We show that such correlations are well-defined only on developable surfaces, i.e. those that can be flattened to form planar surfaces without any stretching or distortion, and preserve the distance between two points on such surfaces after the stretching. If a given curved surface is not developable, but can be approximated as piecewise developable, one may still define and analyze extended correlations on it. Representative examples are presented and analyzed.

scholarly journals URBAN GROWTH SCENARIOS OF A FUTURE MEGA CITY: CASE STUDY AHMEDABAD

2016 ◽  
Vol III-2 ◽  
pp. 165-172 ◽  
Author(s):  
A. Lehner ◽  
V. Kraus ◽  
K. Steinnocher
Keyword(s):  
Remote Sensing ◽  
Urban Growth ◽  
Urban Areas ◽  
Large Scale ◽  
Smart Cities ◽  
Urban Migration ◽  
Indian Government ◽  
Urban Remote Sensing ◽  
Urban Growth Scenarios

The study of urban areas and their development focuses on cities, their physical and demographic expansion and the tensions and impacts that go along with urban growth. Especially in developing countries and emerging national economies like India, consistent and up to date information or other planning relevant data all too often is not available. With its Smart Cities Mission, the Indian government places great importance on the future developments of Indian urban areas and pays tribute to the large-scale rural to urban migration. The potentials of urban remote sensing and its contribution to urban planning are discussed and related to the Indian Smart Cities Mission. A case study is presented showing urban remote sensing based information products for the city of Ahmedabad. Resulting urban growth scenarios are presented, hotspots identified and future action alternatives proposed.

scholarly journals URBAN GROWTH SCENARIOS OF A FUTURE MEGA CITY: CASE STUDY AHMEDABAD

2016 ◽  
Vol III-2 ◽  
pp. 165-172
Author(s):  
A. Lehner ◽  
V. Kraus ◽  
K. Steinnocher
Keyword(s):  
Remote Sensing ◽  
Urban Growth ◽  
Urban Areas ◽  
Large Scale ◽  
Smart Cities ◽  
Urban Migration ◽  
Indian Government ◽  
Urban Remote Sensing ◽  
Urban Growth Scenarios

The study of urban areas and their development focuses on cities, their physical and demographic expansion and the tensions and impacts that go along with urban growth. Especially in developing countries and emerging national economies like India, consistent and up to date information or other planning relevant data all too often is not available. With its Smart Cities Mission, the Indian government places great importance on the future developments of Indian urban areas and pays tribute to the large-scale rural to urban migration. The potentials of urban remote sensing and its contribution to urban planning are discussed and related to the Indian Smart Cities Mission. A case study is presented showing urban remote sensing based information products for the city of Ahmedabad. Resulting urban growth scenarios are presented, hotspots identified and future action alternatives proposed.

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