normal equation matrix after each point has been shlected and 
measured. If the value of this determinant is less than that of 
the apriori estimate, the selection process is terminated. 
11.3. Experimentation with Pass Point Selection Criterion 
  
In order to evaluate the pass point selection technique, a series 
of computer runs were made with fictitious data. The specific data 
reducticn problems were those of single-phozo space resection and 
relative orientation of a stereopair and of a triplet. 
The data reduction programs for space resection and relative 
orientation Sat an option for selecting the optimum location and 
subsequently adding a measurement from this location to the solution. 
The programs functioned as follows. 
An initial least squares solution for the data reduction problem 
was obtained using a minimal data set, for example. four image points 
for a space resection or six for the relative orientation of a stereo- 
pair. Using the results of this solution a prescribed set of image 
coordinates on the photogranh were considered to be candidate locations 
and the selection criterion v' was computed for each of these locations. 
The location which gave the maximum v' was added to the solution as 
shown in equation 8. After a measurement was added to the solution, 
the point was tagged so that it could not be selected again. The 
procedure was repeated until all remaining points were selected and