PRECISE BIOLOGICAL SURFACE MEASUREMENTS IN SOME MEDICAL 
AND DENTAL STUDIES 
L.P.Adams,A.M.Tregidga 
Department of Biomedical Engineering, University of Cape Town, 
Rondebosch 7700, South Africa. 
ISPRS Commission 5 
ABSTRACT 
Non contact, precise measurements of the topography of irregular biological structures 
are important needs of medical and dental investigators.This work presents novel non- 
contact procedures and techniques for the measurement and mapping of a variety of 
biological organisms and features.After an introduction on the scope of biostereometrics 
in South Africa,the paper discusses such diverse topics as the upper cervical spine, 
the "screw" in the rat portal vein, the attrition of denture teeth,regional body surface 
motion, human head movements and the precise measurements of bone growth in a rat model 
using stereo xrays. 
Key words:Biostereometrics; Biological form; Measurements. 
1.INTRODUCTION 
Biostereometrics (medical stereo- 
photogrammetry) has been defined 
as the spatial and spatio-temporal 
analysis of biological form and function 
based on the principles of analytical 
geometry (Karara, 1989). 
  
Computer generated contour plot and 
perspective view of L4 (inferior) 
lumbar vertebra. 
For many years , topographic maps of the 
earths surface have been compiled by the 
method of stereo-photogrammetry, 
    
using a variety of sensors to capture the 
necessary images for measurement 
purposes. The main sensor has been the 
traditional air camera but, with the 
advent of new technologies,use is also 
been made of satellite imagery obtained 
through multi-spectral scanners, video 
solid state cameras, radar imaging and so 
on. Biostereometrics  contemplates the 
"mapping" of biological form, using 
similar techniques and algorithms 
utilised in topographic mapping, but 
adapted for close range imaging. 
In the past , lack of convenient sensors 
inhibited the growth of biostereometrics 
but today there is a growing variety of 
sensors to choose from, which will 
provide stereo images of one sort or 
another and which can be measured to 
yield precise spatial data of biological 
form.These sensors include stereometric 
cameras,stereometric (CCD) video cameras, 
stereometric x-rays, computed axial 
tomography (CAT), magnetic resonance 
imaging (MRI), hologrammetry, ultra sonic 
imaging and direct reflex measurements. 
The  biostereometrics section in the 
department of Biomedical Engineering at 
the University of Cape Town has been set 
up to undertake research projects, in 
conjunction with medical and dental 
researchers, to provide precise 
measurements of biological form.The 
UCT/MRC biostereometric group is engaged 
in numerous research projects using most 
of the sensors listed .