Fine Deformation Monitoring of Ancient Building based on Terrestrial Laser Scanning Technologies Zhou Wei Key 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 Preventative Protection Smart Management 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 Experimental Site – World Cultural Heritage Quickbird Imagery of the Summer Palace Acquired on 22 Mar 2009 Quickbird Imagery of the Summer Palace Acquired 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 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 building Threaten 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 interval79 m Min. range0.4 m Resolution range0.1 mm Max. data acquisition rate pxl/sec. Z+F IMAGER 5006i Terrestrial Laser Scanning Apparatus Leica ScanStation C10 Apparatus Parameter Ambiguity interval300 m Min. range0.1m Resolution range6 mm Max. data acquisition rate pxl/sec. obtain relative long-range data obtain close-range data Handheld 3D Scanner obtain data of single cultural relic or areas cannot reached by the above two scanners

3 rd storey and the interlayer above it Long-range scanning for the whole tower Data Acquisition by Laser Scanning 1 st storey 2 nd 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 1 st storey registration result of the 1 st 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 repairAfter-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 scannersthe 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 3 rd 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 Display Finally

Thank you ！