The Origin of Differential Photogrammetry
We regard two image points at identical locations (x,y) in
adjacent photographs, in a photogrammetric strip.
ep oq
(i ) Citi]
Figure 2
(see figure 2). These two points have systematic image
deformations of the same magnitude. When forming the
difference of their projective relations (1), the
systematic deformation terms F(x,y) are eliminated:
8) o (i+1)
óx xq! - xp" e pxU" (Ng, Eq, Hy) —- Px (Np,Ep,Hp),
6) . vn ^b
Sy yg? - yp? « py "D (Na,Eq,Ha) - Py" (Np,Ep,Hp). (2)
We thus have a formulation of the photographic projection
problem, and indeed for all projections, which is
independent of the knowledge of the exact projective
relationship. No assumption has to be made regarding
systematic image deformation, or even on the nature of
projection.
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