n a prae-post-
shown in fig.
ges are visible,
1etical aspects
al intervention.
the mouth, the
satisfying, as
1 may be the
rocess of the
g.7b: postop
stoperative
- 6586 mre
| 4743 mm
. 36.828 mm
+ 99/8 mn
RAT BY SS mm
2A 045,41 MM
——— 41,23 mn
36.25 mm
7 & 37.44 mm
96
5. DISCUSSION AND OUTLOOK
Applications of photogrammetric measurement tech-
niques referring to clinical diagnosis assistance were
presented.
This technology implies high-precision, non-contact
documentation of clinical findings. On account of the
short time for recording (some 1/10 seconds)
conditioned reflex changes of posture can be ignored.
By synchronously releasing at least 4 cameras it is
possible to determine complex body surfaces, for
instance back and chest shape and faces.
Advantages of the presented method are the quick
measurement process (minimal stress for the patient),
the non-invasiveness (no exposure to radiation) and
little physical contact. In addition to that,
photogrammetric data offer high accuracy and
extensive information of the images. The digital gray
value image can be controlled immediately on a large
format screen and the quality of measurement
material can be checked at once.
The presentation of longitudinal and lateral sections in
anatomical and / or therapeutical relevant areas
facilitate
- the quantification of go down measure
- the documentation of lymph drain
- the consequences for soft tissue volume after
implantation of foreign material.
For the planning of reconstructive interventions it is
useful to look at the surface from different points of
view. The assessment of the physian is supported by
a threedimensional visuell impression of the
momentary status and allows a picture of the planned
result.
Apart from long term studies and follow-ups,
screenings can prove any changes of soft tissue and
the shape. The prae- and post-operative conditions
can be quantified. Posture, muscle tonus and surface
structure are documented. Additional anthropological
investigations can easily be realized, for example the
assessment of growth, consecutive interindividual
comparisons as well as advanced planning.
As a result of that kind of screenings, the deve-
lopment of predicting software is conceivable for the
future. In context of computer-aided therapy-planning
it should be possible to predict changes of soft tissue
after skeletal treatment of the facial part of the skull.
Another goal is the technically supported diagnosis of
dentoalveolus malformations.
The research of measurement systems for intraoral
examination with derivative recording sensors should
be supported.
Photogrammetric measurement is useful for dia-
gnoses and helps to increase objectivization. Dis-
advantages are mainly the amount of time involved
for the complete process, the expenses for hard- and
software and the required expert knowledge.
Future developments aim at the simplification and
wide automation of the recording and evaluation
systems. On the one hand hardware configuration
with 4 fixed CCD-cameras within a calibrated frame
is useful to minimize the time for taking pictures. On
the other hand the conditions for evaluation are
optimal, the calculation of object coordinates results
from spatial intersection. Provided the parameters for
the interior and exterior orientation are known, the
complex calibration process can be reduced to rare
checks.
The results must be presented in clinically relevant
time and shape and should be comprehensible for
non-photogrammetric users.
In addition to that the following advantages can be
recapitulated:
- non-invasive, non-contact
the real measurement time is short
high accuracy, extensive data memory
availability for further check-up
- results are 3D objevt coordinates = open
architecture
- calculation of angles, distances, surfaces, volumes
- presentation of longitudinal and lateral sections,
meshes, shadings.
6. REFERENCES
Gabel, H., et al.; 1995: Photogrammetrische Verfahren
zur Erfassung von menschlichen Körperoberflächen,
VDV-Tagung, Essen
Hinsken,L.;1989: CAP: Ein Programm zur
kombinierten Biindelausgleichung auf Personal-
Computern, Bildmessung und Luftbildwesen, S. 92-
95
Kakoschke,D.,Gáàbel,H.;1996: Dreidimensionale
photogrammetrische Erfassung von Gesichtsober-
flächen, 46. Tagung der Deutschen Gesellschaft für
Mund-Kiefer-,Gesichtschirurgie, Regensburg
Rehling,J.; 1995: Photogrammetrische Messungen am
menschlichen Gesichtsschädel unter Anwendung
digitaler Aufnahme- und Auswertetechniken, Diplom-
arbeit, Labor fir Photogrammetrie FB 11, Vermes-
sungswesen, Universität GH Essen
Woytowicz,D.;1993: PHAUST - A photogrammetric
evaluation system for digital images, Optical 3D
Measurement Techniques Il, A.Gruen and H.Kahmen
(Eds.)
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B5. Vienna 1996
