TERRESTRIAL LASER SCANNING FOR CULTURAL HERITAGE

DOCUMENTATION CASE STUDY : THE OLD PALACE, SERI

MENANTI

1Cheong Siew Chin,

2Ong Chee Wei,

3Prof Dr Halim Setan, and

4Dr Zulkepli Majid

Photogrammetry & Laser Scanning Research Group, Faculty of Geoinformation and Real

Estate, Universiti Teknologi Malaysia (UTM), 81310 UTM Skudai, Johor, Malaysia.

email: 1ahxu813csc@gmail.com,

2 ongcheewei86@gmail.com,

3halim@utm.my,

4zulkepli@utm.my

Abstract

Over the years, modern 3D data collection techniques show significant improvements in

resolution and accuracy. In recent years, the numbers of cultural heritage buildings

documented by using modern three-dimensional (3D) surveying technologies have improved

greatly. The case study historical building is The Old Palace, Seri Menanti, the royal capital

of the state of Negeri Sembilan, Malaysia. The Istana served as the official residence of the

royal family until 1931, before it was converted to a Royal Museum in 1992. The need of

documented the existing high historical value structure was foreseen in United Nation

Educational Scientific and Cultural Organization (UNESCO). In this project, terrestrial

laser scanner is used to capture this cultural heritage building data. This study using

terrestrial laser scanner (TLS) to capture 3D range information to generate 3D building

models. Creation of heritage building model for conservation purposes and the realization of

3D Virtual Model of historical for viewer were concerned by researcher, academician and all

related industries. One of the major purposes is to increase the effectiveness on information

distribution to the public, through visualization dissemination. The development of laser

scanner technology address the market needs in producing 3D model. The advancement of

modelling techniques using point clouds further expand the possibility of using 3D laser

scanner towards the development of higher Level of Detail (LoD) building modelling. This

study discussed the inputs from terrestrial laser scanner to succeed the 3D cultural heritage

building modelling while the focus of this study will be on the investigation of using TLS for

the development of heritage documentation.

Keywords: heritage documentation, terrestrial laser scanning, 3d modelling and level of

details.

1.0 Introduction

There is an increasing demand for three dimensional (3D) city models for many applications

and users worldwide by Dursun & Buhur (2006). One of the major purposes is to increase the

effectiveness on information distribution to the public, through visualization dissemination.

The 3D model of historical building is beneficial for documentation purposes as high valued

cultural heritage do not last forever. The 3D model can be used for documentation,

preservation and future reconstruction of heritage building. The historical structure proposed

in the project is a well known cultural heritage, The Old Palace Seri Menanti, as shown in

Figure 1.0 which located at Kuala Pilah, Negeri Sembilan in Malaysia. In February 2009, the

Unity, Culture, Arts and Heritage Minister Datuk Seri Shafie Apdal announced that the Istana

Lama Seri Menanti is among ten historical structures in Malaysia gazette as a national

heritage, along with Victoria Institution in Kuala Lumpur and The Stadthuys in Malacca The

wooden palace, Seri Menanti Palace was one of oldest cultural heritage that presented the art

and craft of woodcarving skills of Malays people of Malaysia. “The palace was designed

entirely by two local Malay master carpenters and was constructed the traditional way,

without using a single metal nail, and the entire four-storey building is literally held together

only by mortise-and-tenon joints and hardwood dowels and rivets (Anuar, 2007)”.

Figure 1.0: The Old Palace Seri Menanti with Faro Laser Scanner System

The Istana Seri Menanti was itself a replacement for an older, grander palace that was

destroyed in a fire. Today, as with so many traditional crafts, there are very few young

carvers with the skills and the backing to reproduce such a masterpiece. Despite all the

careful preservation work done on the Istana Seri Menanti, eventually, inevitably, time will

take its toll and Malaysia will lose another irreplaceable treasure. In Malaysia, many heritage

buildings with architectural and historical significance that influenced by several architectural

styles such as Malays architecture, Portuguese architecture and Dutch architecture worthy to

be listed or gazetted as National Heritage Building under National Heritage Act 2005 (Act

465) (Salleh and Ahmad, 2009). Documentation of the historical buildings are evolved from

the simple hand-draw sketches to sophisticated 3D virtual reality representation. In particular,

3D modelling plays a significant role in historical buildings visualization. There are several

documentation tools that provide 3D models for visualisation purposes include digital

photogrammetry, laser scanning, Geographic Information System and Computer Aided-

Design (Eppich and Chabbi, 2005).

This project proposes the use of terrestrial laser scanner as the primary tool to produce 3D

model of the Old Palace Seri Menanti. The available methods like photogrammetry are

proven useful but the advancement of new laser scanning technology providing a higher

accuracy choice to carry out this approach, by using 3D laser scanner. The study focuses on

the 3D laser scanning method to generate LoD 4 3D cultural heritage model. The sensors in

FARO Photon 120 system are referring to the digital camera and laser scanner to carry out

data capturing. FARO Photon Laser Scanner 120/20 system integrated with digital camera,

Nikon DSLR D300s is used to measure the 3D geometry data of historical building for

capturing high resolution range data and digital images for texture mapping. For the past

decades, development of laser scanning technology had foreseen that the trend of the cultural

heritage structures require high accuracy 3D modelling technique for photorealistic

presentation and many other GIS application such as cultural heritage conservation and

management concerns/issues.

2.0 Level Of Details (LOD)

As the historical buildings require fast and compact data capturing for the cultural heritage

conservation and management concerns, TLS is an effective tool known by researcher in the

world. This project proposes the use of terrestrial laser scanner as the primary tool to produce

3D model of the Old Palace Seri Menanti. The available methods like photogrammetry are

proven useful but the advancement of new laser scanning technology providing a higher

accuracy choice to carry out this approach, by using 3D laser scanner.

This study is meant to determine the capability of terrestrial laser scanner to achieve high

quality detailed data collection while it is aiming to produce high LoD 3D model. There are

different definitions and standard had been set for the “high quality” in 3D model. In this

study, the high quality was referring to the term LoD that being introduced by CityGML.

One of the concepts of LoD 4 is referred to the OpenGIS City Geography Markup Language

(CityGML) Encoding Standard by Groger et al. (2008) in Open Geospatial Consortium Inc.

Level of Details (LoD) is the standard to reflect independent data collection processes with

differing application requirements. The different LoD simultaneously, enabling the analysis

and visualisation of the same object with regards to different degrees of resolution. The

expecting result is to generate building model follows the LoD standard refers to CityGML.

The concept of LoD of this study was aiming to produce a LoD 2 cultural heritage building

model. The data collection was done by using FARO Photon Laser Scanner 120/20. This 3D

laser scanner was used to capture the building information in point clouds format. With the

integrated digital camera in the Faro laser scanner system; the high resolution digital camera

(Nikon DSLR D300s) was used to capture the RGB value of the cultural heritage building.

All the captured digital images were meant for the colorization of the registered point clouds

from scanning work.

2.1 Requirement for LOD

Kolbe et al. (2005) define five LoD for multi scale modelling for LoD in CityGML. Figure 2

shows the classification of LoD defined by Kolbe. However, it will be within the

responsibility of the user or application to make sure objects in different LOD refer to the

same real-world object (See Figure 3). The coarsest level LOD0 is essentially a two and a

half dimensional Digital Terrain Model, over which an aerial image or a map may be draped.

LOD1 is the well-known blocks model comprising prismatic buildings with flat roofs. In

contrast, a building in LOD2 has differentiated roof structures and thematically differentiated

surfaces.

Vegetation objects may also be represented. LOD3 denotes architectural models with detailed

wall and roof structures, balconies, bays and projections. High-resolution textures can be

mapped onto these structures. In addition, detailed vegetation and transportation objects are

components of a LOD3 model. LOD4 completes a LOD3 model by adding interior structures

for 3D objects. For example, buildings are composed of rooms, interior doors, stairs, and

furniture.

Class of LOD Type of Model Description

LoD0 Regional , Landscape Contains 2.5D DTM

LoD1 City, Region Without roof structures

LoD2 City Districts, Projects Including roof structures

LoD3 Architectural Models (Outside), Landmarks Detailed architecture

LoD4 Architectural models (interior) Including interior model

Figure 2: Classification of LoD defined by Kolbe. (Open Geospatial Consortium, Inc. (2008).

OpenGIS® City Geography Markup LanguagE (CityGML) Encoding Standard: OGC 08-007r1)

Figure 3: The five levels of detail (LOD) defined by CityGML. (Source: IGG Uni Bonn)

Through using Faro laser scanner system, the output will be the registered 3D point clouds of

the cultural heritage building with colour information attached to the point clouds for user’s

visualisation. The further methodology will be the modelling of the Seri Menanti based on

the registered RGB point clouds data from the previous steps. The 3D point clouds registered

will be used in the extraction of the layout of the cultural heritage building structure. This

stage involves the building information extraction based on 3D point clouds.

Besides the manually digitising of the building layout, the automatic building feature

extraction was done in CAD software. The modelling was based on the layout plan extracted

from the point clouds captured. The 3D surveying technology of this terrestrial laser scanning

can help in future preservation work such as building reconstruction and renovation. This

terrestrial laser scanning technique has very high potential and can be beneficial for the

development of Building Information Modelling (BIM) for various applications.

3.0 Heritage Building Modelling

Several international organizations including UNESCO have expressed concern that with the

availability and affordability of rendering systems there is the tendency for interpretations of

world heritage monuments to be taken out of context.

“Many of the cultural heritages in Southeast Asia instrument the development and promotion

of tourism industry in this region. Culture is defined as the whole complex of distinct spiritual,

intellectual, emotional and material features that characterize a particular society or social

group and its way of life. Culture includes the arts and literatures as well as lifestyles, value

systems, creativity, knowledge systems, traditions and beliefs (Ahmad, 2006).”

Paper by Kaartinen et al. (2005) confirms with experiments that laser scanning is more

suitable in deriving building heights, extracting planar roof faces and ridges of the roof

whereas the photogrammetry and aerial images are more suitable in building outline and

length determination. A generic definition of a laser scanner, taken from Bohler and Marbs

(2002) is:

“Any device that collects 3D coordinates of a given region of an object’s surface

automatically and in a systematic pattern at a high rate (hundreds or thousands of points

per second) achieving the results (i.e. three-dimensional co-ordinates) in near real time.”

Laser scanning is at its best in deriving building heights, extracting planar roof faces and

ridges of the roof. In building outline determination, point density, shadowing of trees and

complexity of the structure were the major reasons for site wise variations of the laser

scanner based results. In building length determination with laser scanning, the complexity of

the buildings was the major cause for site wise variation rather than the point density. Height

determination accuracy followed exactly the laser scanning point density. Roof inclination

determination was more accurate when using laser data than photogrammetry, but there exists

large variation in quality due to methods and test sites (i.e. complex buildings). In general the

target plane accuracy is affected by the degree of automation. The target height accuracy

seems to be almost independent of the degree of automation. Besides capturing the 3D

geometry data, the laser scanner acquires also an intensity value of each point. The intensity

is the electronic signal strength obtained by converting and amplifying the backscattered

optical power.

The intensity value can be used for the point cloud visualize analysis purpose. The intensity

of the points can also be further utilized in more sophisticated applications such as the

texturing registration and the categorization by the surface material goods. For applications in

architecture (e.g. building acquisition) it is appropriate and viable to use the laser scanner for

stone-fair mapping or for the modelling of object details, such as sculptures and

ornamentations, in combination with photogrammetry if such objects can be scanned with a

very high point density as mentioned by work of Kersten (2006).

3.1 Phrase of Project

There are four phrases involved in this project (See Figure 4). The data collection phase was

done using the FARO terrestrial laser scanner system to acquire a detailed 3D data. The

second phrase involved data registration in Faro Scene then the 3D modelling for the point

clouds data in AutoCAD 2011. The registered point clouds data from indoor and outdoor will

be modelled and combined. The output of the model is the historical building model that

giving indoor, outdoor model and also the rooftop part was builds based on the design of

rooftop part in other level, e.g. : level 2 and level 3.

The data self checking can be carried individually in all the phases involved as in this

workflow of cultural heritage modelling involved many commercial software. The checking

of the registered point clouds model from Phase 2 can be carried out in Phase 3 using the

visualized model in Pointools Edit 1.1. The editing of point clouds data is allowed in this

Pointools Edit software. The final verification of the building features extract from the 3D

cultural heritage model produced in Phase 2 will be compared with the onsite measurement at

Seri Menanti structure.

Figure 4: Phases in LoD 4 Building Modelling Using Faro Terrestrial Laser Scanner

4.0 Advantages And Drawbacks

The conventional method manually make 3D model of building with 3D CAD by extruding

2D outlines to building height, or modelling manually detailed 3D geometry referring to

drawings and photographs also with 3D CAD. There is also a surveying technique called

triangulation method, which locating a point on site accurately by establishing its distance

from two other points. The angle of inclination must be considered in order to obtain a more

accurate measurement. The approximate scale is included into photographs using scale stick

or measuring tape (Burns, 1989). Although photogrammetry method had been established at

that time, but the maturation still have a lot to be enhanced.

Traditional method requires enormous amount of time to manually processing 3D buildings.

Acquiring measurements from photographs has its advantages because everything seen by the

camera is documented and the photographs are very informative on condition and texture.

The accuracy of the high resolution images captured by digital photogrammetry in the close

range will be affected due to few factors. Figure 5 illustrated the relationship of the methods

used with the considering factors of users in 3D building modelling. Firstly, the raise of the

base to depth ratio increase the accuracy. Besides, data processing using convergent images

will also increase the accuracy rather than images with parallel optical axes. Secondly, the

numbers of images used to restructure the photogrammetric model will affect the accuracy of

digital photogrammetry technique.

The accuracy is enhanced extensively depend on the same common point appears in the

different images. The accuracy will only increase when the geometric configuration is strong

and the measured points are well defined. Lastly, the ground pixel sizes which represent the

ground dimension corresponding to one pixel from the image. The smaller the ground pixel

Phase 4 : Verification

On site Data Checking (using LoD standard in CityGML)

Phase 3 : Results Presentation

Pointool Edit & View Pro 1.1

(.fls .ptl .avi)

SketchUp 8.0 publish in Google Earth

Indoor & Outdoor Model (.wrl) etc.

Phase 2 : Data Processing

Data Registration & Visualisation

- Faro Scene (.fls)

3D Modelling

- AutoCad 2010 (.pcg)

Phase 1 : Data Collection

Faro Photon 120 Nikon DSLR D300s

YES

YES

YES

NO

NO

sizes, the higher the accuracy which refer to the megapixel of the used camera and the image

scale (Clarke et al., 1998; Abdelhafiz, 2000; Fraser, 2001; Gruen and Beyer, 2001; El-Hakim

et al., 2003a).

Method vs Problem Conventional Photogrammetry Terrestrial Laser

Scanner

Time Consuming Field Work ; More X ; Least ; Moderate

High Processing Power X ; Least ; Moderate ; More

Man Power Data Capturing ; More X ; Least ; Moderate

Data Processing X ; Least ; Moderate ; High

Level of Details X ; Least ; Moderate ; High

Accuracy X ; Least ; Moderate ; High

Cost X ; Least ; Moderate ; High

Figure 5: Effectiveness For Different Method In Building Modelling

Currently, as variety of laser scanners are available on the market, varying in measurement

principle, accuracy, capturing speed, measurable distance and angle, price and so on (Boehler

et al., 2003). The high accuracy and resolution of the rapid 3D point clouds acquisition allow

low cost and impressive generation of the as-built engineering models and features extraction

of cultural heritages. In order to get an accurate 3D point cloud data of the whole object

surface there are two factors that need to be concerned such as distance accuracy and space

resolution of the laser scanner (Boehler and Marbs, 2005). One of the advantages of using an

active laser scanning is that it encountered the difficulty with daylight and illumination

conditions.

Work of English Heritage team, United Kingdom (UK) in using laser scanning for the survey

of the cultural heritage had successfully produced a working document for cultural heritage

documentation. “Further work is required to define standard deliverables relevant to cultural

heritage subjects. These standard deliverables should reflect the capabilities of the machines

on the desktop of archaeology and architecture units (Barber et al, 2003)”. The standard

deliverables mention by Barber et al (2009) may be 2D or 3D vector drawings, meshed

models using raking light to highlight particular features or perhaps CAD models with

annotations providing condition assessment or aiding interpretation. Through the research

project of English Heritage in the survey of the Chester Amphitheatre site, Cheshire, it is

found that it is necessary to outline the use of additional data sources to supplement laser

scanning and to decide on suitable data formats for the archiving of point clouds.

5.0 Results

The Figure 6 is the intensity image for interior part of the building in planar view and the

registered raw point clouds indoor data. The distribution of the registration target is important

so that the data registed give a good quality 3D geometric network to the point clouds. Data

surveyed is in high precision and it is helpful to the synchronization of surveying and

processing to take place. The 3D building model is presented at exact coordinate system with

texture mapped. The colorization function allows the texture mapping of RGB information to

the point clouds and make the 3D model more realistic.

Figure 6: (Left) Intensity image of control point in scan data; (Right) Point Cloud data in 3D View

Figure 7: : Front Door Sampling for Modelling and Texturing

Figure 7 displays the front door as a sampling of part of the building structure. The front part

of the Seri Menanti is the main entrance of the building, the front view of the entrance

consists of three scan stations. Before the RGB value attachment, all the point clouds are in

greyscale as the same illustrated in Figure 6.

Figure 8: 3D Visualization Model of Seri Menanti after Point Clouds Colorization. (3D Clear View)

Figure 8 is the data registered for exterior part of the building in clear view. The RGB value

was attached to the point clouds. The exterior model of Seri Meranti consists of 23 scan

surrounding the building.

Figure 9: : Digitizing Layout for Seri Menanti from Point Clouds in AutoCAD 2011

The modelling of the building was basically combined some manual digitizing work with the

automatic generation function in AutoCAD 2011. The point clouds was import into

AutoCAD 2011 to index into 3D modelling format in AutoCAD. The point clouds were then

ready to be used in CAD software for modelling. In this project, the software proposed is

AutoCAD 2011.In Figure 8, the 3D point clouds model was imported into the software and

the digitized layout of Seri Menanti from top view was shown. The registered data was just

like a realistic visualised model of the Seri Menanti. The floating point of the point clouds

might have snapping problem when using manual digitizing. But looking at the point clouds

was giving ±2mm accuracy. Then it might not really an issue as the snapping or digitizing

errors of the building structure are still controlled in mm accuracy. Figure 10 and 11

illustrated the reverse engineering of the 3D Seri Menanti model by sectioning and feature

extraction method based on point clouds. Comparing to the convention building details

survey by total station, this kind of complex historical building can be modelled in shorter

time and with this 3D point clouds it gives more realistic building model.

Figure 10: The building feature extraction using the point clouds data.

The quality of the merging of the different scan data dependent on the amount and quality of

the common points being used for data registration. The building feature extraction was

similar to the layout digitizing in this historical building modelling project.

6.0 Summary

Traditionally way to document valued historical building is not sufficient and cannot

fulfilled the market needs and requirement for various application of it. The 3D laser

scanning was based on the non-contact method and considered to be the most efficient

approach for measuring and modelling of historical building. Conventional method required

operators’ expertise to manually model the building with 3D CAD software. The geometry of

objects is created one by one in CAD and Computer Graphic (CG) software (Kobayashi,

2007). Due to the rapid development of the urban areas, the fast and automatic reconstruction

is needed for the production of the 3D model. For large numbers of building to be modelled

for various purposes and application the automatic generation has reduced the time of model

production through the automatic generation programs. Beside consider the program used to

generate the model, the hardware chosen also important to ensure the data acquisition can

minimise the time consumed.

Figure 11: Digitizing and feature extraction of Seri Menanti

7.0 References

Abdelhafiz, A. 2000. Factors affecting the accuracy of digital photogrammetric applications. Master

thesis, civil engineering department, Assiut university, Assiut, EGYPT, 160 pages.

Ahmad, A. G. 2006. Cultural Heritage of Southeast Asia: Preservation for World Recognition.

Journal of Malaysian Town Plan, Vol. 03 (Issue 01), pp. 52-62.

Anuar, A.H. 2007. A Craftsman’s Marvel: The Wooden Palace of Seri Menanti. Holiday City.Com.

Retrieved on 14 June, 2010 from http://www.holidaycityflash.com/malaysia/seri_menanti.htm

Barber, D.M., Mills, J.P., and Bryan, P.G. 2003. Towards A Standard Specification for Terrestrial

Laser Scanning of Cultural Heritage. XIX CIPA Symposium. 30 September- 4 October 2003.

Antalya, Turkey.

Bohler, W., and Marbs, A. 2002. 3D Scanning Instruments. Proceedings of CIPA WG6 Scanning for

Cultural Heritage Recording. September 1–2. Corfu, Greece: CIPA

Boehler, W., Bordas Vicent, M. and Marbs, A. 2003. Investigating laser scanner accuracy.

Proceedings of the XIXth

CIPA Symposium at Antalya, 30 September – 4 October, 2003. Turkey.

Burns, J. A. 1989. Recording Historic Structures. Washington: The American Institute of Architects

Press.

Clarke, T. A., Wang, X. and Fryer, J. G. 1998. The principal point and CCD cameras. The

Photogrammetric Record, 16(92), pp. 293-312

Eppich, R., and Chabbi, A. 2005. Recording, Documentation, and Information Management for the

Conservation of Heritage Places. Section 3: Condition Assessment: Working with Information.

The Getty Conservation Institute. Vol. II, pp53-59.

Fraser, C. S. 2001. Network design. Chapter 9 in Close Range Photogrammetry and Machine Vision

(Ed. K. B.Atkinson). Whittles, Caithness, Scotland, pp. 256-281.

Gröger, G., Kolbe, T. H., Czerwinski, A., and Nagel, C. 2008. OpenGIS® City Geography Markup

Language (CityGML) Encoding Standard: OGC 08-007r1. Open Geospatial Consortium, Inc.

Gruen, A. and Beyer, H. A. 2001. System calibration through self-calibration. In Calibration and

Orientation of Cameras in Computer Vision (Eds. A. Gruen and T. S. Huang). Springer, Berlin.

Vol. 34, 235 pages, pp. 163-193.

Kaartinen et al. 2005. Accuracy of 3D City Models: Eurosdr Comparison. ISPRS WG III/3, III/4, V/3

Workshop "Laser scanning 2005". September 12-14, 2005. Enschede, the Netherlands, 227-232.

Kersten, T.P. 2006. Combination and Comparison of Digital Photogrammetry and Terrestrial Laser

Scanning for the Generation of Virtual Models in Cultural Heritage Applications. The 7th

International Symposium on Virtual Reality, Archaeology and Cultural Heritage, VAST, pp. 207–

214.

S. Dursun & S. Buhur 2006. 3D City Modelling of Istanbul Historic Peninsula by Combination of

Aerial Images and Terrestrial Laser Scanning Data. Unpublished note. Institute of

Photogrammetry and Geoinformation, Germany.

Salleh, N.H. and Ahmad, A.G. 2009. Fire Safety Management In Heritage Buildings: The Current

Scenario In Malaysia. 22nd CIPA Symposium. 11-15 October. Kyoto, Japan.