Another analytical procedure involving spine deformities in scoliosis, as recorded by stereo X-rays, 
involved the calibration of radiographs. A simplified digital model of the spine is displayed in 
multiple computer-generated graphical projection and line-drawn stereoviews, which provide the doctors 
with means for three-dimensional interpretation of the phenomenon studied 26 . 
A study was conducted at NRC to develop and to test an analytical photogrammetric solution for digital 
modeling of limbs in orthopaedics. Two mirrors were used to record a complete view of the object in 
a single pair of photographs, and to reconstruct a composite photogrammetric model of the irregular 
surface. Subsequent least squares interpolation within the cylindrical system of the enclosed sur- 
face provided data for automated machining of prostheses 24 . Work in this field is also carried 
out at the Universtiy of British Columbia where two NRC designed 23 cm x 23 cm format photogrammetric 
cameras and two 6 cm x 6 cm format cameras are available. The services of a commercial survey office 
were used to produce contour maps of human feet and faces. These contour maps were randomly digitised 
along the contours and the resulting random points fitted by a smooth surface. The latter, defined 
in terms of two sets of orthogonal profiles, was automatically machined by a machining technique known 
as POLYHEDRAL NC. 9, 10, 11, 12 
A stereophotogrammetric system has been established at the Hospital for Sick Children in Toronto with 
the purpose of photographing patients with servere facial deformities. The system consists of three 
Hasselblad 500EL cameras, 6 cm x 6 cm format with matched Carl Zeiss f5.6, 250 mm sonnar lenses. The 
cameras are mounted on a solid horizontal bar which incorporates a command unit for triggering and 
rewinding all three cameras simultaneously. The two outside cameras record the stereo views while 
the centre camera records direct and lateral views. These single mid-line photographs are used for 
facial analysis and corrective designs. The stereophotos are used to produce facial plots which are 
transformed into three-dimensional polyurethane models. The stereophotogrammetry and the three- 
dimensional models are being used to assist in the documentation, pre-operative planning and post- 
operative assessment of severe facial asymmetries. 
Work was continued at Laval University to use photogrammetry in correlating the psychological state 
of a person with his physiognomy and anatomy. 
At the NRC experiments were carried out with photogrammetric contouring of human body by projecting 
a grid pattern to enhance the skin texture. This investigation is extended to substitute contouring 
by photographic recording of moiré fringes obtained from suitably projected fine gratings onto the 
body. 
A theoretical analysis and various practical tests were carried out at NRC to define geometric condi- 
tions affecting stereophotography of the eye background. Based on the tests, an analytical procedure 
was designed to reconstruct three-dimensional models from nearly parallel optical beams of rays, 
characteristics for some existing ophthalmological photo-imaging instruments 25 . Simple photogram- 
metric procedures were modified to allow approximate metric analysis of the eye fundus directly at e © 
doctors laboratories 32, 
Architecture 
The encouraging results of various pilot projects, conducted jointly by NRC and the Restoration Ser- 
vices Division of the Department of Indian and Northern Affairs, provided sufficient justification 
to establish an architectural photogrammetry team within this division 22, 31 . This team has been 
equipped with various terrestrial photogrammetric cameras. The plotting is done presently on analog 
type photogrammetric equipment. Experiments are being carried out to evaluate the advantages of the 
Analytical Plotter in architectural surveys 21. 
Various photogrammetric surveys of historic sites and monuments have been carried out at Laval Univer- 
sity 3, 4 , some of them in cooperation with the Ministère des Affaires Culturelles du Québec. Various 
projects in architectural photogrammetry have been done by commercial photogrammetric companies as 
the result of the interest among federal and provincial government departments in this field. 
Mining and geology 
Terrestrial photogrammetry is applied by Shell Canada Ltd, to measure movements and deformations of 
near vertical excavated walls. The Mining Research Laboratories of the Department of Energy, Mines 
and Resources use photogrammetry in open pit mining, to determine the orientation of geological dis- 
continuities along the slope face and to monitor relative displacements 5. e 
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