fine deformation monitoring of ancient building based on terrestrial laser scanning technologies...
TRANSCRIPT
Fine Deformation Monitoring of Ancient Building
based on Terrestrial Laser Scanning Technologies
Zhou WeiKey Laboratory of Digital Earth, Institute of Remote Sensing and Digital
Earth (RADI), Chinese Academy of Sciences;
International Centre on Space Technologies for Natural and Cultural Heritage (HIST), under the Auspices of UNESCO
23 April 2013
Outline
• Introduction
• Data Acquisition & Processing
• Deformation Monitoring
• 3-Dimensional Modeling
• 3D Information Management System
Research Background
World Heritage
Impact on
Land encroachment
Pollution
……
Human Induced
Uncontrolled Tourism
Resource over-exploitation
Deformation
Meteorological Disasters (Storm)
Forest Disasters (Forest Fire)
……
Natural Influence
Floods & Ocean Disasters (Tsunamis)
Global Change (Greenhouse Effect)
Geohazards (Earthquake)
Solution
General Objective
Fine Mapping & Historical Info
Monitoring & Analyzing
Evaluation & Early Warning
Documentation
Restoration
Publicity
PreventativeProtection
SmartManagement
Space Technologies play an important role in the sustainable development of world heritage!
The Summer Palace, located in a northwestern suburb of Beijing, first built in 1750, largely destroyed in the war of 1860 and restored on its original foundations in 1886 – is a masterpiece of Chinese landscape garden design. It is also presently the best-preserved imperial garden.It was inscripted in the World Heritage List in 1998.
Experimental Site – World Cultural Heritage
Quickbird Imagery of the Summer PalaceAcquired on 22 Mar 2009
Longevity Hill
Kunming Lake
West Lake
17-Arch Bridge
South Island
South Lake
Tower of Buddhist Inscense
As the symbol of the Summer Palace, the Tower of Buddhist Incense represents the highest achievement of traditional Chinese architectural art.
The octagonal, three-storied and quadruple-eaves wood-constructed tower is built on a 20-metre-high granite platform with the Longevity Hill in the north and the Kunming Lake in the south. There’re eight solid lignumvitae columns served as pillars supporting the 36.47-metre-high tower.
the Tower of Buddhist Incense
Due to disrepair, natural disasters, climate change and human activities, the tower is facing great threats.
glazed roof tilesroof ridge animals
Ironstand added to the ancient buildingThreaten the Authenticity!
wooden pillars damaged by the pests
Threaten the Integrity!
Threats to the Tower
Outline
• Introduction
• Data Acquisition & Processing
• Deformation Monitoring
• 3-Dimensional Modeling
• 3D Information Management System
Apparatus Parameter
Ambiguity interval 79 m
Min. range 0.4 m
Resolution range 0.1 mm
Max. data acquisition rate 1 016 727 pxl/sec.
Z+F IMAGER 5006i
Terrestrial Laser Scanning Apparatus
Leica ScanStation C10
Apparatus Parameter
Ambiguity interval 300 m
Min. range 0.1m
Resolution range 6 mm
Max. data acquisition rate 50 000 pxl/sec.
obtain relative long-range data
obtain close-range dataHandheld 3D Scanner
obtain data of single cultural relic or areas cannot reached by the above two scanners
3rd storey and the interlayer above it Long-range scanning for
the whole tower
Data Acquisition by Laser Scanning
1st storey 2nd storey on the scaffold and indoor
white points are the artificial targets
Point Clouds Registration
Due to complicated objects overlapping caused by observing from different points of view and the geometric characteristics of the object itself, it’s hard to obtain complete information of a certain target just from one scan station. The solution is to use the same group of artificial targets which are placed in the scene and measured from each of the overlapping scan stations.
indoor point clouds of the 1st storey
registration result of the 1st storey
registration result of the 3 stories
registration result of the whole tower and its surroundings
Point Clouds Registration
In order to improving the registration precision, 92 scan stations were set up for data acquisition. Moreover, some more artificial targets are placed to increase redundant observations.
The registration error of point cloud data is less than 5 millimetres.
Produce CAD Drawings
the slices
of point
clouds
CAD drawings
we get many cross-sections in each storey, and then each cross-sections can outline structural feature of building.
The elevations of the Tower of Buddhist Incense
The sections of the Tower of Buddhist Incense
Produce CAD drawings
Outline
• Introduction
• Data Acquisition & Processing
• Deformation Monitoring
• 3-Dimensional Modeling
• 3D Information Management System
In order to estimate the dip and dip direction of every pillar, we get the cross-sections from the top and the bottom part of the pillar segment in each storey, and then eight cross-sections can be obtained from one integral pillar including the pillar segment inside the double eaves above the third storey.
Cross-Section of the Pillars
Estimate Dip & Dip Direction
cross sections of the pillars’ bottom in each story
The tower has a slight inclination towards the southeast, and the dip
angle is around 0.7 degree.
dip direction of the Pillars Dip angle of the Pillars
the dip and dip direction of every pillar can be worked out by connecting the centre points of each pillar
Estimate Dip & Dip Direction
Outline
• Introduction
• Data Acquisition & Processing
• Deformation Monitoring
• 3-Dimensional Modeling
• 3D Information Management System
Pre-maintenance Under repair After-maintenance
we must record the status quo and history information elaborately and comprehensively. Laser scanning technologies are applied to 3D model building of the tower, and the detail property of the tower components can be recorded based on 3D models.
The Tower of Buddhist Incense has been repaired every few years.
3D Modeling
Roof ridge animal scanned by handheld 3D scanners the lion's model
Eaves scanned by Z+F laser scanners the model of eaves
3D Modeling
3d model of the paintingstexture capture & point clouds of paintings in the 3rd storey
point clouds capture of the xumi support model of the xumi support
3D Modeling
Rendered 3D Model of the Whole Tower
Outline
• Introduction
• Data Acquisition & Processing
• Deformation Monitoring
• 3-Dimensional Modeling
• 3D Information Management System
It turns out that building the database of 3D models and picture archives help to preserve the original data of cultural heritage, including the spatial relationship information and other important types of data.
3D Information Management System
The tower has a complicated structure, so the 3D models of the tower are divided into three stories to manage, and the same kind of components is put in a category in a single storey.
3D Information Management System
maintenance organization
maintenance record
maintenance time
dialog box of component maintenance information
3D Information Management System
shooting time of photo of the tower components
Pre-maintenance
Under repair
After-maintenance
dialog box of component maintenance information
3D Information Management System
Video DisplayFinally
Thank you！