det (N, + bl wb) 
  
det (N,) 
where, 
bY wb is the contribution from the partial derivatives of either 
the x or y collinearity equation with respect to the elements 
of exterior orientation. 
(14) 
The value of v can be expanded to ; 
det (N, * b! wb) iq 
v = = 1 + wb M. b 11 
det (N. ) 
Where M. is the inverted 6 x 6 block diagonal portion of the normal 
equations from equation 6 associated with the jth photograph. Omitting 
the addition of 1 in the computation of v for each candidate point 
by equation 11, the final form used for the selection criterion is, 
v = wb M, bl 12 
This gives the contribution from the 31 photograph. :It is proposed 
that the total contribution be the sum of the contribution from each 
photograph on which the point is measured. With this idea in mind, 
the criterion for the selection of pass points may be stated as follows. 
The measurement from the total 1ist of candidate measurements which 
should be added to the solution is the one which gives the maximum 
value of, po