1. 
Se ~ 
PT ove 
pos Ww ^ 9^ A Mi 
  
Figure 2 - Feature Boundaries 
The output. from the outline algorithm consisted of the 
feature boundary and any accompanying operator-identified 
points of interest, all expressed as row and column pixel 
values in the local picture coordinate system. All 
additional picture information was discarded, reducing the 
amount of feature information to a manageable amount. Also, 
the background noise was greatly reduced. Obviously, this 
method would not function well in image regions of low 
contrast and smooth texture - it is feature based and 
requires well-defined feature boundaries. 
A general purpose transformation routine was developed to 
match feature outlines from film to film. It was based on a 
standard six parameter affine transformation, with 
parameters for scaling on the x and y axes, translation in x 
and y, rotation, and non-orthogonality of the axes. Points 
in System 1 can be transformed to System 2 by: 
cosá 0 
cosf -sinf S, X, T 
sind cosé 
  
  
  
  
sinß cosf S, Yi Ty 
Scale on the x axis 
Scale on the y axis 
where S 
5, 
ß = Rotation 
6 
T 
T 
= Non-orthogonality 
= Translation in x 
= Translation in y 
Note that this transformation is usually implemented with 
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