Geostatistics and Structure from Motion Techniques for Coastal Pollution Assessment along the Policoro Coast (Southern Italy)

The coastal system, with its physical chemical and biological components, is the place where the lithosphere, atmosphere and hydrosphere intersect and interact, and in which human activity has a considerable impact on the balance of the whole ecosystem. The aim of this study is to assess the health of the coastal environment in a natural protected area in Policoro (Italy). Sand samples have been collected and analysed to detect the presence of environmental contaminants and pollutants (heavy metals). A photogrammetric survey was carried out using an unmanned aerial vehicle (UAV), and an updated orthophoto of the area was obtained using the Structure from Motion (SfM) processing technique. Geostatistical techniques have been used to assess the distribution of the contaminants in the study area.

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Regional differences in mortality rates during the COVID-19 epidemic in Italy

Disaster Medicine and Public Health Preparedness ◽

10.1017/dmp.2020.486 ◽

2020 ◽

pp. 1-22

Author(s):

Danila Azzolina ◽

Giulia Lorenzoni ◽

Luciano Silvestri ◽

Ilaria Prosepe ◽

Paola Berchialla ◽

...

Keyword(s):

Regional Differences ◽

Southern Italy ◽

Meta Analysis ◽

Analysis Data ◽

Mortality Rates ◽

Northern Italy ◽

Admission Rates ◽

Considerable Impact ◽

The Difference ◽

Disease Diffusion

Abstract Objective The COVID-19 outbreak started in Italy on February 20th, 2020, and has resulted in many deaths and intensive care unit (ICU) admissions. This study aimed to illustrate the epidemic COVID-19 growth pattern in Italy by considering the regional differences in disease diffusion during the first three months of the epidemic. Study design and methods Official COVID-19 data were obtained from the Italian Civil Protection Department of the Council of Ministers Presidency. The mortality and ICU admission rates per 100 000 inhabitants were calculated at the regional level and summarized via a Bayesian multilevel meta-analysis. Data were retrieved until April 21st, 2020. Results The highest cumulative mortality rates per 100 000 inhabitants were observed in northern Italy, particularly in Lombardia (85.3, 95% credibility intervals [CI] 75.7–94.7). The difference in the mortality rates between northern and southern Italy increased over time, reaching a difference of 67.72 (95% CI = 66–67) cases on April 2nd. Conclusions Northern Italy showed higher and increasing mortality rates during the first three months of the epidemic. The uncontrolled virus circulation preceding the infection spreading in southern Italy had a considerable impact on system burnout. This experience demonstrates that preparedness against the pandemic is of crucial importance to contain its disruptive effects.

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Implementation of InfraRed Thermographic surveys in complex coastal areas: the case study of Polignano a Mare (southern Italy)

10.5194/egusphere-egu21-3264 ◽

2021 ◽

Author(s):

Lidia Loiotine ◽

Marco La Salandra ◽

Gioacchino Francesco Andriani ◽

Eliana Apicella ◽

Michel Jaboyedoff ◽

...

Keyword(s):

Rock Mass ◽

Structure From Motion ◽

Southern Italy ◽

Thermal Imager ◽

Rock Masses ◽

Field Surveys ◽

Thermal Images ◽

Thermal Anomalies ◽

Rock Face

InfraRed Thermography (IRT) spread quickly during the second half of the 20th century in the military, industrial and medical fields. This technique is at present widely used in the building sector to detect structural defects and energy losses. Being a non-destructive diagnostic technique, IRT was also introduced in the Earth Sciences, especially in the volcanology and environmental fields, yet its application for geostructural surveys is of recent development. Indeed, the acquisition of thermal images on rock masses could be an efficient tool for identifying fractures and voids, thus detecting signs of potential failures. Further tests of thermal cameras on rock masses could help to evaluate the applicability, advantages and limits of the IRT technology for characterizing rock masses in different geological settings. We present some results of IRT surveys carried out in the coastal area of Polignano a Mare (southern Italy), and their correlation with other remote sensing techniques (i.e. Terrestrial Laser Scanning and Structure from Motion). The case study (Lama Monachile) is represented by a 20 m-high cliff made up of Plio-Pleistocene calcarenites overlying Cretaceous limestones. Conjugate fracture systems, karst features, folds and faults, were detected in the rock mass during field surveys. In addition, dense vegetation and anthropogenic elements, which at places modified the natural setting of the rock mass, represent relevant disturbances for the characterization of the rock mass. In this context, IRT surveys were added to the other techniques, aimed at detecting the major discontinuities and fractured zones, based on potential thermal anomalies.&#160; IRT surveys were carried out in December 2020 on the east side of the rock mass at Lama Monachile site. Thermal images were acquired every 20 minutes for 24 hours by means of a FLIR T-660 thermal imager mounted on a fixed tripod. Ambient air temperature and relative humidity were measured during the acquisition with a pocketsize thermo-hydrometer. A reflective paper was placed at the base of the cliff to measure the reflected apparent temperature. In addition, three thermocouple sensors were fixed to the different lithologic units of the rock face. These parameters, together with the distance between the FLIR T-660 and the rock face, were used in order to calibrate the thermal imager and correct the apparent temperatures recorded by the device, during the post-processing phase. Successively, vertical profiles showing the temperature of the rock face over time were extracted from the thermograms. Thermal anomalies were correlated with stratigraphic and Geological Strength Index profiles, obtained by means of field surveys and Structure from Motion techniques. The presence of fracture and voids in the rock mass was also investigated.

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Accuracy Assessment of Unmanned Aerial Vehicle (UAV) Structure from Motion Photogrammetry Compared with Total Station for a Deformed Slope

Understanding and Reducing Landslide Disaster Risk - ICL Contribution to Landslide Disaster Risk Reduction ◽

10.1007/978-3-030-60319-9_32 ◽

2020 ◽

pp. 291-299

Author(s):

Vera Hui Loo ◽

Chou Khong Wong

Keyword(s):

Unmanned Aerial Vehicle ◽

Structure From Motion ◽

Accuracy Assessment ◽

Total Station ◽

Aerial Vehicle

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Experimental Study on 3D Measurement Accuracy Detection of Low Altitude UAV for Repeated Observation of an Invariant Surface

Processes ◽

10.3390/pr10010004 ◽

2021 ◽

Vol 10 (1) ◽

pp. 4

Author(s):

Sha Gao ◽

Shu Gan ◽

Xiping Yuan ◽

Rui Bi ◽

Raobo Li ◽

...

Keyword(s):

Experimental Study ◽

Unmanned Aerial Vehicle ◽

Structure From Motion ◽

Measurement Accuracy ◽

Test Plot ◽

3D Measurement ◽

Difference Model ◽

Repeated Observations ◽

Aerial Vehicle ◽

Low Altitude

Low-altitude unmanned aerial vehicle (UAV) photogrammetry combined with structure-from-motion (SFM) algorithms is the latest technological approach to imaging 3D stereo constructions. At present, derivative products have been widely used in landslide monitoring, landscape evolution, glacier movement, volume measurement, and landscape change detection. However, there is still a lack of research into the accuracy of 3D data positioning based on the structure-from-motion of unmanned aerial vehicle (UAV-SFM) technology, itself, which can affect the measurable effectiveness of the results in further applications of this technological approach. In this paper, validation work was carried out for the DJI Phantom 4 RTK UAV, for earth observation data related to 3D positioning accuracy. First, a test plot with a relatively stable surface was selected for repeated flight imaging observations. Specifically, three repeated flights were performed on the test plot to obtain three sorties of images; the structure from motion and multi-view stereo (SFM-MVS) key technology was used to process and construct a 3D scene model, and based on this model the digital surface model (DSM) and digital orthophoto map (DOM) data of the same plot with repeated observations were obtained. In order to check the level of 3D measurement accuracy of the UAV technology itself, a window selection-based method was used to sample the point cloud set data from the three-sortie repeat observation 3D model. The DSM and DOM data obtained from three repeated flights over the surface invariant test plots were used to calculate the repeat observation 3D point errors, taking into account the general methodology of redundant observation error analysis for topographic surveys. At the same time, to further analyze the limits of the UAV measurement technique, possible under equivalent observation conditions with the same processing environment, a difference model (DOD) was constructed for the DSM data from three sorties, to deepen the overall characterization of the differences between the DSMs obtained from repeated observations. The results of the experimental study concluded that both the analysis of the 3D point set measurements based on window sampling and the accuracy evaluation using the difference model were generally able to achieve a centimeter level of planimetric accuracy and vertical accuracy. In addition, the accuracy of the surface-stabilized hardened ground was better, overall, than the accuracy of the non-hardened ground. The results of this paper not only probe the measurement limits of this type of UAV, but also provide a quantitative reference for the accurate control and setting of an acquisition scheme of the UAV-based SfM-MVS method for geomorphological data acquisition and 3D reconstruction.

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REPRESENTATION AND DIGITALIZATION OF STONE THEATRES IN EASTERN SICILY: THE PALAZZOLO ACREIDE THEATER

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ◽

10.5194/isprs-archives-xlii-2-w11-475-2019 ◽

2019 ◽

Vol XLII-2/W11 ◽

pp. 475-479

Author(s):

G. Di Gregorio

Keyword(s):

Structure From Motion ◽

3D Model ◽

Southern Italy ◽

Three Dimensional ◽

Cultural Value ◽

Geometric Conditions ◽

Dense Matching ◽

Laser Scanners ◽

First Results ◽

Quality And Reliability

Abstract. The ancient theatres in Sicily, in southern Italy and along the countries facing the Mediterranean Sea basin, constitute a reality of incomparable cultural value. Regarding the research on the ancient theatres of eastern Sicily, few studies have been recently dealt with different methodologies. In the last years some practices have been done using 3D laser scanners for the theatres of Syracuse, Taormina and Morgantina, as well as the Syracuse amphitheatre and Taormina Odeon, just obtaining very interesting results. Lately the theatre of Palazzolo Acreide (Syracuse) has been studied, with Structure From Motion (SFM) and Dense Matching methodologies. From these experience, conclusions could be drawn on the quality and reliability of the elaborations realised with the SFM methodologies. We really know that these systems are today representing one of the fastest growing areas of examination, on which several software houses are investing. The study was chosen both for the small size of the building, and for the particular geometric conditions typical of the architecture of ancient theatres. This because their three-dimensional trend varies continually in the three variables X, Y, Z. The purpose of the work was to check whether the latest releases of these systems of survey allow today more than yesterday, a rapid digitalization and representation of the enormous archaeological cultural heritage. Various software were used, to verify the practicality and operation, the choice then fell on the Zephyr of 3DFlow, kindly available by the manufacturer, whose results were quite agreeable. The possibility offered by the program of a graphical tracing of polylines on the textured 3D model, has been a considerable advantage. Therefore the results obtained by modeling and surveying of the Palazzolo Acreide theatre have been compared, with the survey of the Syracuse, Taormina and Morgantina theatre performed using 3D laser scanners. First results of the research are matter of the following work.

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Autonomous Unmanned Aerial Vehicle for Post-Disaster Management With Cognitive Radio Communication

International Journal of Ambient Computing and Intelligence ◽

10.4018/ijaci.2021010102 ◽

2021 ◽

Vol 12 (1) ◽

pp. 29-52

Author(s):

Raja Guru R. ◽

Naresh Kumar P.

Keyword(s):

Unmanned Aerial Vehicles ◽

Processing Technique ◽

High Accuracy ◽

Image Processing Technique ◽

Radio Communication ◽

Dynamic Changes ◽

General Graph ◽

Vision Based Navigation ◽

Aerial Vehicle ◽

Post Disaster

Unmanned aerial vehicles (UAV) play a significant role in finding victims affected in the post-disaster zone, where a man cannot risk his life under a critical condition of the disaster environment. The proposed design incorporates autonomous vision-based navigation through the disaster environment based on general graph theory with dynamic changes on the length between two or multiple nodes, where a node is a pathway. Camera fixed on it continuously captures the surrounding footage, processing it frame by frame on-site using image processing technique based on a SOC. Identifies victims in the zone and the pathways available for traversal. UAV uses an ultrasonic rangefinder to avoid collision with obstacles. The system alerts the rescue team if any victim detected and transmits the frames using CRN to the off-site console. UAV learns navigation policy that achieves high accuracy in real-time environments; communication using CRN is uninterrupted and useful during such emergencies.

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