filing modes for removal of any residual y parallax by moving the left correlation scan in the 
appropriate direction. 
The correlation level signal is used to control the speed of the x and/or y movement during 
the automatic orientation or profiling modes. 
The slope magnitude signals are used in the distortion correction computer together with 
the o, o, X, y, z, bx, by and bz sensors to compute the proper distortion signals which are 
fed to the correlation deflection and the orthophoto control circuitry. 
Contour Segments: 
The slope direction signals are converted into 400 hz and fed to the contour segment print 
CRT, where they produce the correct rotation for the contour segment line, such that it is 
printed out normal to the slope direction. 
The contour segment print CRT's output is controlled by digital logic, receiving its input 
from a number of photo transistors sensing the passing of each line on the Z-readout scale. 
The digital logic is arranged to allow the operator to select from one to ten scale intervals 
as the contour interval. For each contour interval reached the contour segment CRT is 
activated for a 5 m. sec. exposure of the contour segment line on the film. The operator 
can also select each fourth or fifth contour interval to be intensified. 
The contour segment line appears as a yellow/red line in order to separate it from the blue 
orthophoto image. This allows concurrent exposure of the orthophoto and contour seg- 
ments on a colour negative. The two images can then be separated by standard colour 
separation techniques. 
Orthophoto: 
The orthophoto signal is extracted in an independent orthophoto loop, when the yellow/ 
red orthophoto scan is optically reduced by a factor of six, then imaged and centered on 
the same part of the diapositive as the viewing system and the correlation scan. The yellow/ 
red pass characteristic assures that an interference free signal will be obtained. 
The scan in the flying spot scanner is generated and corrected to be proportional to the 
momentary scale of the image on the diapositive, including all the deformations caused by 
the orientation and slope parameters, in order that the undeformed ortho printout scan