47 
The conclusion is that the camera is well suited to measurements as the in 
terior orientation does not vary between the pictures and as the residuals are 
relatively small, independent and normally distributed. 
dr 
r—>• r mm 
Fig. 11. 
Pentax Takumar 688210. Upper cur 
ve: radial distortion, mean of six de 
terminations, Table 5. Lower curve: 
Standard error of the mean radial 
distortion, s dr . Pooled standard error 
of unit weight (image co-ordinates), 
5q = 3.5 jum. 
8.2. CALIBRATION OF THE STEREO-MEDICAL-NIKKOR 
8.2.1. 7he Camera 
In the application of photogrammetric methods to medicine and odontology, 
it is often difficult to find a suitable metric camera. The objects to be photo 
graphed are commonly of such sizes that the ordinary stereocameras (b = 1.2 
m and 0.4 m) are not suitable. Some of the difficulties are listed below. 1) The 
cameras have a negative scale which is too small. 2) The photography demands 
much space. 3) The image area is only partly used. 4) The base-height-ratio is 
to small. 5) The accuracy is not optimal etc. 
To overcome these difficulties the Section of Medical Photogrammetry has 
developed a stereocamera from two Nikon F cameras with Medical Nikkor 
lenses (f = 200 mm). 
The lack of flatness of the emulsion is of less importance because of the large