"Politehnica" University of TimisoaraCivil Engineering Faculty

Surveying and Cadastre

Name of the project:

The Lifelong Learning Programme ErasmusEPOCHE IPExcellence in Photogrammetry for Open CulturalLandscape & Heritage Education

Contract number: 2012-1-GR1-ERA10-10609

June 2-16, 2013 Thassos Island, Northern Greece

SORIN HERBAN and CARMEN GRECEAsorin.herban@ct.upt.ro

http://www.upt.ro

Contract number: 2012-1-GR1-ERA10-10609

Financed by :

EDUCATION IN THE "POLITEHNICA" UNIVERSITY OF TIMISO ARA

Timisoara - important academic city withstrong economical and cultural tradition

�the ”Politehnica” University of Timisoara is oneof the largest, well-known technical universities inCentral and Eastern Europe .Central and Eastern Europe .

�the "Politehnica" University of Timisoara has 10faculties and several independent departmentsdelivering the academic programs which aremodern, relevant, intellectually stimulating andrepresent the highest quality in their respectivedisciplines.

�the branch of Surveying and Cadastre from thefaculty of civil Engineering offers full-time degreeprograms in Romanian language only.

founded in 1920

Faculty of Engineering in Hunedoara

Faculty of Mechanical Engineering

Faculty of Management in Production and Transportation

Faculty of Electrical and Power Engineering

Faculty of Electronics andTelecommunications Engineering

Faculty of Faculty of

Faculty of Industrial ChemistryAnd Environmental Engineering

Faculty of Civil Engineering ( founded in 1941 )

Faculty of Automation andComputers

Arhitecture

DEPARTMENTSSteel Structures and Structural MechanicsCivil Engineering and EquipmentsOverland Communication Ways, Foundations and Cadastral Survey (1991)Hydrotechnical Engineering

PROGRAM OF SURVEYING AND CADASTRE IN THE ’’POLITEHNICA’’ UNIVERSITY OF TIMISOARA

PROGRAM FOUNDED IN 1991 - accredited specialization

number of places number of graduates

The consolidation strategy of the specialization covers the following objectiv es:�Continuous development of the curriculum and syllab uses, in conformity with the evolution of the techniques in the domain of Geodes y, and in correlation with similar Romanian and European Union institutes;� PhD development studies for the teaching staff and specialized training for external professors;�Development of some current research fields in cada stre such as: informatization of the land register, land information systems, GIS, s atellite technologies.

3D SCANNING?

DOES IT WORK?

THREE DIMENSIONAL MODEL?

WHAT IS THE FINAL DELIVRABLE?

Three dimensional models of physical objects are rapidly becoming more affordable in manyfields such as inspection, navigation, object identification, visualization, and animation. Photorealistic models are also needed for the cultural heritage digital archiving. These models arebeneficial in case of loss or damage, interaction without risk of damage, virtual tourism andvirtual museums.

The importance of the terrestrial 3Dlaser scanners is highlighted by thepractical applications they have inmany domains, such as: historicconservation by means ofassessment and monitoring ofchurches and other old buildings,churches and other old buildings,part of cultural heritage; architecture;land surveying; archaeologicalstudies; bridge structures; assessingthe risk of slope instability alongtransport corridors and highwaysurveys etc.

Designing a dynamic framework forplanning and development, based on3D models can help to create themaster plan of any populated area.

3D modeling (also known as meshing) is the process of developing a mathematicalrepresentation of any three-dimensional surface of object via specialized software. Theproduct is called a 3D model.

The process of generating 3D models consists of several wellknown steps which are: capturing and points recovering, surfacesreconstruction, texture mapping, and visualization. At thecapturing and points recovering step both the image basedapproach and the range based approach can be employed.

The suitable approach is selected by considering the applicationtype, the geometric accuracy, realism, automation level, and cost.type, the geometric accuracy, realism, automation level, and cost.

Apart from enabling the visualization of all components of anobject, 3D modeling facilitates a separate visualization of thescanned object’s parts. The components and the materials haveproperties called visualization properties such as contrast oralbedo that can be easily highlighted.

Historical buildings play an important role in cultural heritage scenario: their main value isdue overall to age, artistic and structural features and to surrounding environment.Rehabilitation and maintenance of historical architecture includes reinforcement ofconfiguration, adjustment of geometry and other technical procedures. The 3D laserscanning technology is one of the important techniques methods to acquire spatial data. Itscans the architecture of the objective point by point in very short time; records and createpoint clouds to simulate the shape by computer; reconstructs 3D model with high accuracy.

Timisoara, the city with the most historical buildings in Romania, has a large project ofrehabilitation and economic revitalization of historical districts. This program of rehabilitationof buildings does not only their outer coating. The program is more complex, covers morecomponents, such as strengthening and repair of buildings (structures strengthen theresistance of the building, restoration of the roof where applicable), improved interiorcomfort, (replacement of windows, fitting with the minimum utility necessary) and improvinginterior and exterior appearance (restoration of the ornaments and particularly facades,architectural style and reconstruct the original color of the building).

One of the most ancient buildings is “The old fortress” which was built out of soil, stone, brickand oak. In the XIth century, in 1052, the perimeter of the old fortress was where today's PalaceTheater and Liberty Square. “The new fortress” , modern, much larger, was built between1723-1765. On April 25, 1723 fundamental stone was placed in the city under the leadership ofGovernor Mercy. The entire construction of fortifications costed 20 million Austrian florins.

Historical buildings from Timisoara

Building knowledge, is used for its maintenance and safety, can be well supported by aspatial model, thanks to its better capability of communication, design representation andemployment inside GIS environments. 3D visualization, if compared to 2D one, provides amore complete and effective tool for building investigation, which can start from each pointof view, both for planimetric data (plan and horizontal profiles) and altimetric ones (verticalsections), and for wall geometry.

Difference between 2D and 3D clasic representation

Apply laser scanning technology to historical archi tecture reconstruction

Typical Total Stations may measure up toeight distances per second. In contrast,the 3D laser scanner is capable ofmeasuring up to 50,000 distances persecond. In phase-based measurementtechnology, the phase difference ismeasured between the reflected beamand the transmitted amplitude modulatedcontinuous wave laser beam.

Data acquisitionData registrationData preprocessingSurface fittingProducts producingPoint cloud phase

Detail collections by close-range photogrammetry

Generally speaking, 3D model reconstructed by scan data has no texture. Besides, scandata cannot keep the details well, especially details such as structure and texture. Fordetail structure or special areas that need special treatment we can use the close-rangephotogrammetry method, which produces orthoimages and linear drawings.

As we all know, it is hard to disposeAs we all know, it is hard to disposecontrolling points around every interestedarea, because not only it costs more timebut also sometimes it is impossible todispose controlling points. The informationwe need is only the exact scale and notthe absolute position. Thus, we chooselinear character to rectify image of thechosen plan.

Window details with 1 mm points accurate

Conclusion

• 3D laser scanning technology can acquire 3D point cloud quickly with highaccuracy. This meets the needs of historical architecture surveying andprotection. 3D laser scanning technology can replace traditional measuringmethods completely in historical architecture surveying. 3D point cloud can begained by laser scanner, then construct the 3D model. In addition, detailstructure can be obtained by close-range photogrammetry method, whichproduces the orthoimage and linear drawing.

• Surveying Historical architecture based on 3D laser scanning technology can notonly reduce field work, improve efficiency, but also provide different kinds ofproducts such as 3D model, CAD construction drawing and so on. 3D laserscanner is growing towards high speed, high accuracy, large range and multi-information etc at present. All these will impulse laser scanning application tohistorical architecture surveying and protection.

LASER SCANNING FOR ENGINEERING

Terrestrial laser scanning can be successfully used in engineering because, by means ofit, the entire structure of an object can be captured, facilitating analyses like cablemovements, pillar deformations etc.

Monitoring of the PRAID SALT MINE’s surface through a combined approach –topographic measurements, GPS and 3D scanning

� The terrain displacements can be determined by comparing different epochs ofmeasurements;

� 3D scanning is feasible and convenient for displacements determining withcentimeter precision.centimeter precision.

Data obtained through scanning is useful in preventing the disastrous consequences of landslides

20112012

Collecting the field data

• The scanning was realized with the Leica ScanStation C10;• Resolution: 5 cm;• Density: 400 points / m 2;• Accuracy: < 1cm;• Approximately 80 000 000 (mil.) points were collect ed;• 8 scanning stations.

If we would lay out in a line these points at a dis tance of 10 cm one to another, we could make a circuit of

the world.

The digital model of the scanned terrain was obtained was obtainedfollowing the use of a data filtering algorithm using Autocad CIVIL 3D 2013.

Creating the Digital Terrain Model

Before clearing the noise

The Digital Terrain Model

After clearing the noise

RESULTS

A comparison was effected by overlapping the 2 surfaces resulted after theprocessing of the scans taken in 2011, respectively in 2012, having as result adigging volume of 7064 m3 and a filling volume of de 5525 m3of earth material.

These data is a little exaggerated due to gaps areas from the surface where thelaser beams encountered blockage in line-of-sight.

Gaps in the scanned surfaces

2011 2012

To overcome this problem, the number of the scanning stations should be increased.

Virtual benchmarks

The virtual points form a grid of 44 points located over the areas with high density of the pointcloud in order to obtain maximum accuracy.

The heights of the virtual points and the differences between them

DIFFERENCES DETERMINED IN THE 4 TH POINT

2011 2012

DIFFERENCES DETERMINED IN THE 5 TH POINT

2011 2012

DIFFERENCES DETERMINED IN THE 34 TH POINT

2011 2012

CREATING LONGITUDINAL AND CROSS SECTIONS

The longitudinal sections were created having as a basis the 3Dsurfaces.

AUTOMATIC GENERATION OF THE CROSS SECTIONS USING AUTOCAD CIVIL 3D 2013

Conclusion

• Although Terrestrial Laser Scanning stands a bit behind airborne scanning,it has a great potential for being used for landslides monitoring, even at alarge scale.

• The greatest disadvantage of this technology is the fact that it offersinformation on the vertical modifications and not on the horizontal plane, butinformation on the vertical modifications and not on the horizontal plane, butin combination to classical surveying engineering methods, it offers preciseresults.

Monitoring of a viaduct from a new bypass

Considering current concerns having to do, on the one hand, with the development andimproving of the Romanian modern road network that should offer superior comfort,safety and efficiency in traffic and should observe current policies in sustainabledevelopment, and on the other hand the impact of climate changes on road and materialquality and on technical building solutions, the importance of real-time monitoring when itcomes to terrestrial means of communications becomes all the more visible.

The localization of the studied viaduct

The studied viaduct was constructed with a support structure of reinforced soil. Themonitoring methodology of over time behaviour involved topo-geodetic measurementsperformed weekly as well as terrestrial laser scanning technology through which aspatial image of the embankment and of the reinforced support wall is obtained.

Positioning of the monitoring benchmarks on

the viaduct’s paramentparament

Current work consists in the processing of the first session of terrestrial laser scannermeasurements and comparing the resulted 3D model with the designed model, followedby other sessions of measurements which will be conducted in order to characterize thebehavior in time of the viaduct.

The 3D model obtained by scanning – on the left and the 3D designed model of the viaduct – right

Overlapping of the designed 3D model with the one obtained by TLS

Conclusion

• The laser scanner provides a complex representation of an object fromspace (3D representation) by effecting measurements horizontally andvertically, at pre-set intervals. By means of repetition, at certain intervals, ofthese measurements, the evolution in time of deformations and settlementsof the observed construction can be obtained.

• Given the advantages of using the terrestrial laser scanning technique - thedata obtained is difficult or even impossible to measure with traditionaldata obtained is difficult or even impossible to measure with traditionaltopographic instruments, the probability to have unscanned areas becauseof shading is minimum, since this technology has the ability to scan fromdifferent angles and overlap the results, the entire visible structure of someobjects is not only measured in certain predefined points, thus giving thepossibility of precise investigations - perfect for following such objects,which are very sensitive and have a high risk of losing stability.

-- Thank you for your attention Thank you for your attention --

June 2-16, 2013 Thassos Island, Northern Greece