The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Voi. XXXVII. Part B5. Beijing 2008 
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designed hardware for generating a teeth arch 3D model and 
face 3D model in automated mode and original software for 
models setting up and occlusion analysis. 
For forecasting (and then documenting) the results of treatment 
an original photogrammetric system for fast textured face 3D 
model generation is developed. The 3D model for occlusion 
visualization and documenting includes a face 3D model and 
teeth arches 3D model. It is used for presenting the teeth 
appearance before and after treatment. 
2. 3D RECONSTRUCTION 
To meet dentist requirements for dentistry analysis, treatment 
planning and documenting it is needed to obtain accurate high 
resolution teeth arch 3D models and textured 3D models of 
patient face. Due to different requirements to those two types of 
models two photogammetric systems is developed. 
A photogrammeric system for automated teeth arch 3D model 
generation (Figure 1.) includes two digital high resolution 
cameras, high resolution structured light projector and PC- 
controlled rotation positioning stage. It allows producing high 
resolution 3D of teeth arch in automated mode. 
Figure 1. Photogrammetric system for teeth arch 3D model 
reconstruction 
A system for patient face 3D model acquisition is also based on 
digital cameras and structured light projector. For minimizing 
the acquisition time cameras and projector work in 
synchronized mode allowing to get required set of images in a 
short time period of about 0.5 sec. 
2.1 Teeth 3D model generation 
The following requirements are established to a system for teeth 
arch occlusion analysis for satisfying investigation purposes: 
- High accuracy of 3D reconstruction 
- High resolution of tooth 3D model 
- Short time for producing teeth arch 3D models 
- The possibility of real occlusion reconstruction 
- The possibility of occlusion investigation 
To meet these requirements the configuration of 
photogrammetric system including two digital IEEE 1394 
cameras of high resolution (2 Mpxel), structured light projector 
with resolution of 1440x1080 piexels and PC-controlled 
rotation positioning stage is chosen. For automated 
corresponding problem solution coded light is applied providing 
robust and fast scanning. 
The system is calibrated using original technique (Knyaz, V., 
2002) for estimating camera interior and exterior orientation 
parameters and for determining the parameters of positioning 
stage rotation axis (Knyaz, V., 2002, 2005). Special calibration 
test field with coded targets is used for system parameters 
determination in automated mode. The calibration technique 
provides residuals of co-linearity conditions for the reference 
points after least mean square estimation at the level of 0.005 
mm. This accuracy is quite adequate for the concerning 
problem. 
For whole teeth arch 3D model generation a set of scans at 
various plaster model positions is acquired. The number of 
scans and their orientation are the subject of user choice. All 
scans are transformed to global coordinate system using the 
results of rotation axis parameters estimation (Figure 2.). This 
first order scans alignment serves as an initial approximation for 
accurate scan registration by iterative closest point algorithm 
(Besl, 1992). 
Figure2. 3D reconstruction process 
After scan merging a single mesh 3D model is generated using 
interpolating mesh algorithm (Curless, 1996). 
For acquiring teeth arch 3D model using the described 
automated procedure it is required about 5 minutes. The 
resulting 3D model has accuracy of 0.03 mm and includes about 
1 000 000 points. Both upper and lower teeth arch 3D models 
are produced for further occlusion analysis. 
2.2 Face 3D model acquisition 
For forecasting (and then documenting) the results of treatment 
an original photogrammetric system for fast textured face 3D 
model generation is developed (Figure 3).