470
Perspective center
When measuring the coordinates of the fiducial marks the exact
location of H' is unknown and the measurements are refered to a
system (x')> (y') with origin in the point of intersection of the two
lines connecting opposite fiducial marks and with the (y')-axes as the
projected image of the y'-axes. As <o is the primary rotation the coordi
nates of H' are
tarup
O') H'= —c —— , (/) H '= c tanw
LUbCO
Therefore:
O') =*'— 0')h' » O') = / + O') if
When measuring the fiducial marks the image coordinate system
may be translated and rotated in the system of the measuring instru
ment X, Y. Accordingly
X — A 0 + OO cosa — (y') sina
Y = Y 0 + (x*) sina + {y'i cosa