Simple Photogrammetric Methods with ARPENTEUR ... 
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Figure 1 : Wild P32 image of the Aleyrac site (France). 
3. SIMPLE 3-D MEASUREMENT 
3.1 3-D Measurement Principles 
The result of each primitive adjustment is used to simplify the measuring process. That is to say that for a computed primitive of an 
object, from one measurement in one image it is possible to compute and measure by correlation to its homologous in the other 
images. 
We employ four steps (Figure 8) in our Semi-automated Primitive Measurement Method, considering that a geometric primitive has 
been measured from a set of 3-D points visible on two images : 
• Point P can be computed from one image by intersection of an image ray (pi, 01) and the geometric primitive (the cylinder in 
Figure 8 is defined by seven parameters in an earlier process from a set of 3-D points); 
• P is projected as p2 onto the second image; 
• Point p2 is used as an approximate position to initiate the area based correlation process; 
• Point p3 is the result of the correlation; pi and its homologous p3 are used for the computation of the 3-D co-ordinates of P1. 
Step 4 
The point p3 is the result of the correlation. 
It is used as the homologous point of pi for 
the computation of the 3-D coordinates of PI 
Step3 
The point p2 is used as 
approximate value for 
the correlation process 
Figure 2: Steps of the Semi-automated Primitive Measurement Method in ARPENTEUR