-10- 
SCANNING PATTERNS 
Scanning pattern refers to the shape of the path traced out by the scan 
ning spot as it moves continuously throughout the scanning area or raster. 
In ARES the scanning pattern must be adaptive to both of the following two 
functions which are being performed simultaneously: 
(1) The presentation of a high quality image to the operator in which 
all the detail present in the original photographs is preserved and, if 
possible, made more visible. 
(2) The estimation of X and Y parallax by the detection of time 
differences between the left and right video signals. 
In addition, a scanning pattern should be relatively simple to produce 
and should remain stable over long periods of time without the need for fre 
quent readjustment. 
Figure 7 illustrates several scanning patterns which have had applica 
tion in photogrammetrie instruments. 
X " “ 
—\ 
\ 
\ 
\ 
V— 
\— 
v- 
\ 
(a) TV 
Figure 7.- Scanning patterns. 
■■