scholarly journals 3D Imaging of CRP and Ultrasonic Tomography to Detect Decay in a Living Adult Holm Oak (Quercus ilex L.) in Sardinia (Italy)

2021 ◽  
Vol 11 (3) ◽  
pp. 1199
Author(s):  
Michele Puxeddu ◽  
Francesco Cuccuru ◽  
Silvana Fais ◽  
Giuseppe Casula ◽  
Maria Giovanna Bianchi
Keyword(s):  
Quercus Ilex ◽  
Integrated Approach ◽  
Holm Oak ◽  
Diagnostic Process ◽  
Deformation Pattern ◽  
Ultrasonic Tomography ◽  
Non Invasive ◽  
Close Range Photogrammetry ◽  
Close Range ◽  
Living Adult

A field-integrated methodology using 3D ultrasonic tomography supported by close range photogrammetry (CRP) has been developed and evaluated as a tool to detect the presence and patterns of decay forms in a living adult holm oak (Quercus ilex L.) in an urban green area of the city of Cagliari, Sardinia, Italy. Close range photogrammetry was used to compute a high resolution 3D model of the studied tree, texturized with natural colors. Moreover, following the implemented workflow process it was possible to evaluate the deformation pattern of the studied tree over time. In a second step of our integrated approach, and in order to diagnose the state of health of the inner part of the studied tree in a non-invasive way, laboratory and in situ non-invasive ultrasonic techniques were applied. The results of the close range photogrammetry analysis supported the optimal design of the 3D ultrasonic tomography of the living adult holm oak. Ultrasonic tomography is one of the most powerful non-destructive testing techniques for the full-volume inspection of a structure. It produced physical information on the inner structure of the stem of the investigated tree. The results of the study show that the integrated application of close range photogrammetry and 3D ultrasonic tomography is a powerful tool for a highly accurate and objective evaluation of the external and internal decay of trees and for monitoring their conservation states. With the fully integrated approach, the diagnostic process aimed to prevent instability and the failure of trees can be greatly improved.

scholarly journals Decay detection in an ancient column with combined close-range photogrammetry (CRP) and ultrasonic tomography.

2021 ◽  
Author(s):  
Giuseppe Casula ◽  
Silvana Fais ◽  
Francesco Cuccuru ◽  
Maria Giovanna Bianchi ◽  
Paola Ligas ◽  
...  
Keyword(s):  
High Resolution ◽  
Diagnostic Process ◽  
Ultrasonic Tomography ◽  
Invasive Approach ◽  
Non Invasive ◽  
Close Range Photogrammetry ◽  
Close Range ◽  
Non Destructive ◽  
Non Destructive Techniques

<p>The diagnosis of the conservation state of monumental structures from constraints to the spatial distribution of their physical properties on shallow and inner materials represents one of the key objectives in the application of non-invasive techniques. <em>In situ</em>, CRP and 3D ultrasonic tomography can provide an effective coverage of stone materials in space and time. The intrinsic characteristics of the materials that make up a monumental structure and affect the two properties (i.e., reflectivity, longitudinal velocity) through the above methods substantially differ. Consequently, the content of their information is mainly complementary rather than redundant.</p><p>In this study we present the integrated application of different non-destructive techniques i.e., Close Range Photogrammetry (CRP), and low frequency (24 KHz) ultrasonic tomography complemented by petrographycal analysis based essentially on Optical Microscopy (OM). This integrated methodology has been applied to a Carrara marble column of the <em>Basilica of San Saturnino</em>, in Byzantine-Proto-Romanesque style, which is part of the Paleo Christian complex of the V-VI century. This complex also includes the adjacent Christian necropolis in the square of <em>San Cosimo</em> in the city of Cagliari, Sardinia, Italy. The column under study is made of bare material dating back probably to the first century A.D., it was subjected to various traumas due to disassembly and transport to the site, including damage caused by the close blast of a WWII fragmentation bomb.</p><p>High resolution 3D modelling of the studied artifact was computed starting from the integration of proximal sensing techniques such as CRP based on Structure from Motion (SfM), with which information about the geometrical anomalies and reflectivity of the investigated marble column surface was obtained. On the other hand, the inner parts of the studied body were successfully inspected in a non-invasive way by computing the velocity pattern of the ultrasonic signal through the investigated materials using 3D ultrasonic tomography. This technique gives information on the elastic properties of the material related with mechanical properties and a number of factors, such as presence of fractures, voids, and flaws. Extracting information on such factors from the elastic wave velocity using 3D tomography provides a non-invasive approach to analyse the property changes of the inner material of the ancient column. The integrated application of <em>in situ</em> CRP and ultrasonic techniques provides a full 3D high resolution model of the investigated artifact. This model enhanced by the knowledge of the petrographic characteristics of the materials, improves the diagnostic process and affords reliable information on the state of conservation of the materials used in the construction processes of the studied monumental structure. The integrated use of the non-destructive techniques described above also provides suitable data for a possible restoration and future preservation.</p><p><strong> </strong></p><p><strong>Acknowledgments: </strong>This work was partially supported by FIR (Fondi integrativi per la Ricerca) funded by the University of Cagliari (Italy). The authors would also like to thank the Ministero dei Beni e delle Attività Culturali. Polo Museale della Sardegna and Arch. Alessandro Sitzia for their kind permission to work on the <em>San Saturnino Basilica</em>.</p>

scholarly journals Decay Detection in an Ancient Column with Combined Close-Range Photogrammetry (CRP) and Ultrasonic Tomography

Minerals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1114
Author(s):  
Giuseppe Casula ◽  
Silvana Fais ◽  
Francesco Cuccuru ◽  
Maria Giovanna Bianchi ◽  
Paola Ligas ◽  
...  
Keyword(s):  
High Resolution ◽  
Low Frequency ◽  
Ultrasonic Tomography ◽  
Proximal Sensing ◽  
Non Invasive ◽  
Close Range Photogrammetry ◽  
Resolution Model ◽  
Close Range ◽  
Ultrasonic Techniques ◽  
High Resolution Model

This study presents the integrated application of a few non-destructive techniques, i.e., Close Range Photogrammetry (CRP), and low frequency (24 kHz) ultrasonic tomography complemented by petrographical analysis. The aim here is to assess the conservation state of a Carrara marble column in the Basilica of San Saturnino, which is part of a V-VI century Palaeo Christian complex in the city of Cagliari (Italy). The high resolution 3D modelling of the studied artifact was computed starting from the integration of proximal sensing techniques, such as CRP based on the Structure from Motion (SfM) technique, which provided information on the geometrical anomalies and reflectivity of the investigated marble column surface. The inner parts of the studied body were inspected successfully in a non-invasive way by computing the velocity pattern of the ultrasonic signal through the investigated materials, using 3D ultrasonic tomography. The latter was optimally designed based on the 3D CRP analysis and the locations of the source and receiver points were detected as accurately as possible. The integrated application of in situ CRP and ultrasonic techniques provided a full 3D high resolution model of the investigated artifact, which made it possible to evaluate the material characteristics and its degradation state, affecting mainly the shallower parts of the column. The 3D visualisation improves the efficiency, accuracy, and completeness of the interpretative process of data of a different nature in quite easily understood displays, as well as the communication between different technicians.

scholarly journals Close-Range Photogrammetry and Infrared Imaging for Non-Invasive Honeybee Hive Population Assessment

2018 ◽  
Vol 7 (9) ◽  
pp. 350 ◽  
Author(s):  
Luis López-Fernández ◽  
Susana Lagüela ◽  
Pablo Rodríguez-Gonzálvez ◽  
José Martín-Jiménez ◽  
Diego González-Aguilera
Keyword(s):  
Computer Vision ◽  
Infrared Imaging ◽  
Imaging Techniques ◽  
Population Level ◽  
Non Invasive ◽  
Close Range Photogrammetry ◽  
3D Geometry ◽  
Thermographic Imaging ◽  
Close Range ◽  
Bee Colonies

Close-range photogrammetry and thermographic imaging techniques are used for the acquisition of all the data needed for the non-invasive assessment of a honeybee hive population. Temperature values complemented with precise 3D geometry generated using novel close-range photogrammetric and computer vision algorithms are used for the computation of the inner beehive temperature at each point of its surface. The methodology was validated through its application to three reference beehives with different population levels. The temperatures reached by the exterior surfaces of the hives showed a direct correlation with the population level. In addition, the knowledge of the 3D reality of the hives and the position of each temperature value allowed the positioning of the bee colonies without the need to open the hives. This way, the state of honeybee hives regarding the growth of population can be estimated without disturbing its natural development.

scholarly journals Gravitational deformation of ring-focus antennas for VGOS: first investigations at the Onsala twin telescopes project

2019 ◽  
Vol 93 (10) ◽  
pp. 2069-2087 ◽  
Author(s):  
Michael Lösler ◽  
Rüdiger Haas ◽  
Cornelia Eschelbach ◽  
Ansgar Greiwe
Keyword(s):  
Path Length ◽  
Deformation Pattern ◽  
Radio Telescopes ◽  
Close Range Photogrammetry ◽  
Geodetic Vlbi ◽  
Gravitational Deformation ◽  
Close Range ◽  
Main Reflector ◽  
Ray Path ◽  
First Time

Abstract The receiving properties of radio telescopes used in geodetic and astrometric very long baseline interferometry (VLBI) depend on the surface quality and stability of the main reflector. Deformations of the main reflector as well as changes in the sub-reflector position affect the geometrical ray path length significantly. The deformation pattern and its impact on the VLBI results of conventional radio telescopes have been studied by several research groups using holography, laser tracker, close-range photogrammetry and laser scanner methods. Signal path variations (SPV) of up to 1 cm were reported, which cause, when unaccounted for, systematic biases of the estimated vertical positions of the radio telescopes in the geodetic VLBI analysis and potentially even affect the estimated scale of derived global geodetic reference frames. As a result of the realization of the VLBI 2010 agenda, the geodetic VLBI network is currently extended by several new radio telescopes, which are of a more compact and stiffer design and are able to move faster than conventional radio telescopes. These new telescopes will form the backbone of the next generation geodetic VLBI system, often referred to as VGOS (VLBI Global Observing System). In this investigation, for the first time the deformation pattern of this new generation of radio telescopes for VGOS is studied. ONSA13NE, one of the Onsala twin telescopes at the Onsala Space Observatory, was observed in several elevation angles using close-range photogrammetry. In general, these methods require a crane for preparing the reflector as well as for the data collection. To reduce the observation time and the technical effort during the measurement process, an unmanned aircraft system (UAS) was used for the first time. Using this system, the measurement campaign per elevation angle took less than 30 min. The collected data were used to model the geometrical ray path and its variations. Depending on the distance from the optical axis, the ray path length varies in a range of about $$\pm \,1\,\hbox {mm}$$±1mm. To combine the ray path variations, an illumination function was introduced as weighting function. The resulting total SPV is about $$- \,0.5$$-0.5 mm. A simple elevation-dependent SPV model is presented that can easily be used and implemented in VLBI data analysis software packages to correct for gravitational deformation in VGOS radio telescopes. The uncertainty is almost $$200\,\upmu \hbox {m}$$200μm ($$2\sigma $$2σ) and is derived by Monte Carlo simulations applied to the entire analysis process.

Structure, biomass and production of a resprouted holm-oak (Quercus ilex L.) forest in NE Spain

Vegetatio ◽  
1992 ◽  
Vol 99-100 (1) ◽  
pp. 51-59 ◽  
Author(s):  
M. J. Lled� ◽  
J. R. S�nchez ◽  
J. Bellot ◽  
J. Boronat ◽  
J. J. Iba�ez ◽  
...  
Keyword(s):  
Quercus Ilex ◽  
Holm Oak ◽  
Ne Spain

Performance Dynamic Tracking and Analysis System of Road Traffic Signs

2011 ◽  
Vol 130-134 ◽  
pp. 2404-2408
Author(s):  
Jun Ma ◽  
Wen Ying Su
Keyword(s):  
Road Traffic ◽  
Performance Testing ◽  
Analysis Software ◽  
Traffic Signs ◽  
Detection Algorithms ◽  
Close Range Photogrammetry ◽  
Dynamic Tracking ◽  
Data Acquisition Software ◽  
Close Range ◽  
Analysis System

In view of the heavy workload and possible intervention to the normal traffic flow during the performance testing of road traffic signs, this paper is designed to present a system that can be installed in an automobile and automatically track and analyze the performance of traffic signs. The system consists of a carrying vehicle, GPS, IMU, area-array cameras, frame grabbers, data acquisition software and data analysis software. Based on close-range photogrammetry technology, the system is designed with a set of effective road traffic signs automatic detection algorithms, which can automatically measure and analyze the properties of road traffic signs, such as dimensions, headroom and verticality of the column, etc.

scholarly journals ILRS Reference Point Determination Using Close Range Photogrammetry

2021 ◽  
Vol 11 (6) ◽  
pp. 2785
Author(s):  
Michael Lösler ◽  
Cornelia Eschelbach ◽  
Thomas Klügel ◽  
Stefan Riepl
Keyword(s):  
Reference Point ◽  
Reference Points ◽  
Geodetic Reference System ◽  
Unscented Transformation ◽  
Local Ties ◽  
Close Range Photogrammetry ◽  
Crucial Component ◽  
Space Geodetic Techniques ◽  
Close Range ◽  
Point Determination

A global geodetic reference system (GGRS) is realized by physical points on the Earth’s surface and is referred to as a global geodetic reference frame (GGRF). The GGRF is derived by combining several space geodetic techniques, and the reference points of these techniques are the physical points of such a realization. Due to the weak physical connection between the space geodetic techniques, so-called local ties are introduced to the combination procedure. A local tie is the spatial vector defined between the reference points of two space geodetic techniques. It is derivable by local measurements at multitechnique stations, which operate more than one space geodetic technique. Local ties are a crucial component within the intertechnique combination; therefore, erroneous or outdated vectors affect the global results. In order to reach the ambitious accuracy goal of 1 mm for a global position, the global geodetic observing system (GGOS) aims for strategies to improve local ties, and, thus, the reference point determination procedures. In this contribution, close range photogrammetry is applied for the first time to determine the reference point of a laser telescope used for satellite laser ranging (SLR) at Geodetic Observatory Wettzell (GOW). A measurement campaign using various configurations was performed at the Satellite Observing System Wettzell (SOS-W) to evaluate the achievable accuracy and the measurement effort. The bias of the estimates were studied using an unscented transformation. Biases occur if nonlinear functions are replaced and are solved by linear substitute problems. Moreover, the influence of the chosen stochastic model onto the estimates is studied by means of various dispersion matrices of the observations. It is shown that the resulting standard deviations are two to three times overestimated if stochastic dependencies are neglected.

Application of close range photogrammetry in structural health monitoring by processing generated point cloud datasets

2021 ◽  
Author(s):  
Ali Mirzazade ◽  
Cosmin Popescu ◽  
Thomas Blanksvärd ◽  
Björn Täljsten
Keyword(s):  
Health Monitoring ◽  
Point Cloud ◽  
Laser Scanning ◽  
Point Clouds ◽  
Optical Data ◽  
Small Scale ◽  
Relevant Parameter ◽  
Bridge Inspection ◽  
Close Range Photogrammetry ◽  
Close Range

<p>In bridge inspection, vertical displacement is a relevant parameter for both short and long-term health monitoring. Assessing change in deflections could also simplify the assessment work for inspectors. Recent developments in digital camera technology and photogrammetry software enables point cloud with colour information (RGB values) to be generated. Thus, close range photogrammetry offers the potential of monitoring big and small-scale damages by point clouds. The current paper aims to monitor geometrical deviations in Pahtajokk Bridge, Northern Sweden, using an optical data acquisition technique. The bridge in this study is scanned two times by almost one year a part. After point cloud generation the datasets were compared to detect geometrical deviations. First scanning was carried out by both close range photogrammetry (CRP) and terrestrial laser scanning (TLS), while second scanning was performed by CRP only. Analyzing the results has shown the potential of CRP in bridge inspection.</p>

Habitat selection patterns of common cranes Grus grus wintering in holm oak Quercus ilex dehesas of central Spain: Effects of human management

1996 ◽  
Vol 75 (2) ◽  
pp. 119-123 ◽  
Author(s):  
Mario Díaz ◽  
Elvira González ◽  
Rodrigo Muñoz-Pulido ◽  
Miguel Angel Naveso
Keyword(s):  
Habitat Selection ◽  
Quercus Ilex ◽  
Holm Oak ◽  
Central Spain ◽  
Grus Grus ◽  
Human Management
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