GV-18 
18 
parallel camera axes (normal orientation). Base and focus are adjustable in 
steps. The camera has no shutters and flash light is used for exposure. 
A photogrammetric method has been used to measure respiratory movements. 
Literature: 
S. Hagberg, P. Hjelmström and J. Adams-Ray: The effect of long-acting infiltration anesthesia 
with efocaine on the respiratory movements at rest postoperatively. The Scandinavian Journal 
of Clinical & Laboratory Investigation. 1954. Vol. 6, No. 2. 
In dentistry several problems have been treated by photogrammetry. Measure 
ments of gingival capillaries are performed by means of a stereomicroscope of 
Zeiss construction, and various auxiliary instruments have been constructed. 
Literature: 
G. Forslund: Stereoscopic Capillaroscopy. A method for photogrammetric investigation and registra 
tion of the periphereal bloodvessel system, with special regards to the gingiva and oral mucosa. 
(Acta Odontológica Scandinavica 1953, Vol 11, Table 1.) 
2) Biology 
At the Division of Photogrammetry (RIT) terrestrial photogrammetry has 
been applied to measuring of deformations of growing trees as well as to certain 
other geometric measurements on trees. (Hellmont-Skoglund.) 
3) X-ray photogrammetry and evaluation of results 
Variations in volume of the canine liver have been studied by means of 
roentgen photogrammetry by S. Hagberg and P. Hjelmstrom. In the liver of a 
dog small silver pellets are fixed. The positions of these pellets are computed 
from an X-ray film doubly exposed to two X-ray tubes. The computations 
were carried out on punched cards in IBM machines. The method is still used. 
Literature: 
P. Hjelmstrom: Determination, by the aid of an X-ray stereoscopic method, of volume variations 
of the liver of animals; Photogrammetric Engineering 1953/4. 
Intra-oral radiography has been subject to some developement. The work in 
this field by Berghagen-Hjelmstrom, which was reported at the VII Congress 
in Washington, has been followed up, and improvements in the equipment have 
been achieved. A similar apparatus for extra-oral radiography is being built. 
Literature: 
1. Berghagen—Hjelmstrom: A new method for intra-oral radiography (Photogrammetric Engineering 
Vol XIX nr 4 sept 1953 655—659). 
2. Berghagen—Hjelmstrom: Intra-oral rontgenfotografering i belysning av tredimensionell geome- 
trisk beskrivning. (Svensk Tandlákartidskrift nr 2 1954 s. 135.) 
3. Berghagen—Hjelmstrom: The principles underlying three-dimensional intra-oral radiography. 
(Will appear in Acta Odentologica Scandinavica.) 
4. Berghagen—Hjelmstrom: Radiographic mensuration of the bone changes in the limbus alveolaris 
in a case of marginal periodontal disease. (Will appear in Acta Odontológica Scandinavica.) 
5. Berghagen: Metodik for lagebestámning och behandling av retinerade horntánder, foretrádesvis 
overkákshorntánder. (Will appear in Svensk Tandlákartidskrift.) 
F) Miscellaneous 
At the Division of Photogrammetri (RIT) several problems have been treated 
by terrestrial photogrammetric methods. For photography stereocameras and