INTEGRATION OF STEREOPHOTOGRAMMETRY AND TRIANGULATION-BASED 
LASER SCANNING SYSTEM FOR PRECISE MAPPING OF CRANIOFACIAL 
MORPHOLOGY 
a a b 
Z.Majid , H. Setan , A. Chong 
a Faculty of Geoinformation Science & Engineering, University Technology Malaysia - zulkepli@fksg.utm.my 
b School of Surveying, University of Otago, Dunedin, New Zealand - albert.chong@surveying.otago.ac.nz 
Commission V, WG V/6 
KEY WORDS: Photogrammetry, Laser Scanning, Integration, Medicine, Precision 
ABSTRACT: 
The paper describes the first Malaysian Craniofacial soft tissue 3D imaging system which was developed based on the integration of 
stereophotogrammetry and triangulation-based laser scanning system. The main purposes of developing the imaging system are to 
provide a non-contact method for craniofacial anthropometric measurement and fast and radiation free 3D modelling of craniofacial 
soft tissue. The stereophotogrammetric system consists of high resolution digital cameras setup as three stereo cameras placed at 
the left, front and right sides of the patient. The system was also add-up with another extra two digital cameras setup in convergent 
mode at bottom left and bottom right of the patient. The combination of all the cameras allowed for the accuracy improvement of 
craniofacial anthropometry through a novel technique called “natural features technique”. In the natural features technique, the 
images acquired from the camera system were used to digitize the natural features on the human face. Photogrammetric 
triangulation method was used to calculate the 3D coordinates of the features. The cameras was highly synchronized (0.2miliseconds) 
using a new external shutter controller. The stereophotogrammetric system was designed to be operated in battery system for mobile 
data capturing purposes. Apart from the camera system, the developed stereophotogrammetric system was completely designed with 
the object space control frame. The new patient’s chair and photogrammetric control frame has been designed and developed. The 
object distance is 700mm. Special-built camera calibration device was designed and developed to calibrate each camera 
individually. The camera was placed at the camera platform to capture eight convergent images of the 3D test field. The self 
calibration bundle adjustment process was carried out using Australis software to calculate the calibration parameters. The developed 
stereophotogrammetric system was integrated with the triangulation-based laser scanning system. Two eye-safe Minolta VI-910 
laser scanners was setup at right and left side of the patient and near to the stereophotogrammetric system with object distance of 
1000mm. For the purposes of scanning the craniofacial morphology, the scanners was setup with middle lens (focal length = 14mm) 
and fine mode resolution with one scan mode. The scanners scanned one after another with 19 seconds scan period (complete scan). 
With the optimum setup, two scan images was acquired which covered the craniofacial area (from right ear to left ear and the hair 
line to bottom part of the chin). The texture data of the craniofacial area was also captured. Both scanners were calibrated using 
calibrated object. In the data collection session, the patient sited on the chair with the head placed at the middle of the control frame. 
The complete system was firstly tested using mannequin to determine the accuracy and precision. Both stereo images and scans 
data was processes separately. The DVP digital stereophotogrammetric workstation was used to carry out the photogrammetric 
orientation of the stereo images. The vectorization module was used to measure the 3D coordinates of the craniofacial landmarks. 
The laser scan datasets involved with few data processing steps which included the registration process, merging process, editing 
process, smoothing process and texturing process. The processing tasks were carried out using the RapidForm 2004 software. At 
final stage, the craniofacial landmarks measured from stereophotogrammetric system were registered onto the 3D model developed 
from the laser scanners. The research also involved with the development of the craniofacial database system which used to store the 
captured datasets. The results show that both stereophotogrammetry and laser scanning system was an effective system to be used 
in craniofacial mapping. Both systems provide high accuracy non-contact measurement method. The accuracy of the craniofacial 
landmark measurement is 0.2mm with one standard deviation, while the accuracy of the 3D model is 0.3mm with one standard 
deviation. 
1. INTRODUCTION 
1.1 Introduction 
A prototype craniofacial imaging system has been developed in 
the study. As 3D photogrammetry system for acquiring 
craniofacial spatial data, the developed system completely 
consisted of data acquisition system and data reduction system. 
2. CRANIOFACIAL SPATIAL DATA ACQUISITION 
SYSTEM 
2.1 General 
The developed prototype craniofacial spatial data acquisition 
system is the combination of two 3D photogrammetry systems 
namely stereophotogrammetry and 3D laser scanner. The 
prototype system also involved with the special built object 
space control. The object space control consists of special built 
craniofacial chair and calibrated photogrammetric control frame. 
Figure 1 show the conceptual design of the system, while Figure 
2 shows the physical design of the prototype system.