311 
| 7. FUTURE DEVELOPMENTS IN DIGIDENT 
rat can | 
] since | Image acquisition in vivo has already been done, and seems not to be the real problem. Nevertheless, image acquisition under 
Microsoft Windows™ has to be implemented, especially an appropriate frame grabber has to be found, always taking into 
digital | consideration, that standard components have to be used. Illumination devices have to be constructed and the influence of 
in the | illumination on the surface reconstruction of non-targeted objects has to be investigated. Good illumination is one of the most 
These. | important conditions in photogrammetry to gain best results. On the other hand, matching algorithms have to be developed that 
| serve accurate and reliable results even with only two images. Better results have to be reached, therefore better algorithms have to 
d two | be developped. For deformation analysis features have to be investigated, that allow the description of the three-dimensional 
ng the position and orientation of every single tooth. Same effort has to be put on a three-dimensional matching algorithm to derive the 
| lot of spatial movements and rotations of the teeth. : 
)blems Last but not least all algorithms have to be put under a user interface that can be used by a dentist. What we have to do is not to 
explain photogrammetry to a dentist, but to provide a tool that can be used by them without realizing what's going on in the black 
box. 
y used 8. ACKNOWLEDGEMENTS 
d. On 
(0,8 DigiDent is developed for Landeskrankenhaus Graz, Prof. Droschl. Thanks for all the support and help given to us. 
to the 
inated | 9. REFERENCES 
Achilli V., 1992. Stereophotogrammetry: a possible employment in the dental field. IAPRS, Vol. XXIX, part B5. 
Baltsavias E.P., 1992, Multiphoto Geometrically Constrained Matching. Ph.D. Mitteilungen Nr. 49, Institute of Geodesy and 
Photogrammetry, ETH Zurich. 
Beyer H.A., 1992, Geometric and Radiometric Analysis of a CCD-camera based Photogrammetric Close Range System. 
  
| Mitteilungen Nr. 51, Institute of Geodesy and Photogrammetry, ETH Zurich. 
Gruen A., 1986. Photogrammetrische Punktbestimmung mit der Bündelmethode. Mitteilungen Nr. 40, Institute of Geodesy and 
Photogrammetry, ETH Zurich. 
Gruen A. and Stallmann D., 1991, High accuracy edge matching with and extension of MPGC-matching algorithm. SPIE, 
Vol. 1526, Industrial Vision Metrology, Winnipeg, p. 42-55. 
Mollersten L.; 1989, Comparison between guided and freehand preparation. The journal of prosthetic dentistry, August 1989, 
Vol. 62, number 2. 
Vozikis E., 1985. Some theoretical and practical aspects on the use of photogrammetry in medicine. Biostereometrics '85, 
Cannes France, SPIE Vol. 602 p. 211-218. 
  
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2 IAPRS, Vol. 30, Part 5W1, ISPRS Intercommission Workshop "From Pixels to Sequences", Zurich, March 22-24 1995