pected. 
he esti- 
rea be- 
atching 
Line D 
lowing 
(n 
  
arting 
d, we 
d. In 
"wn in 
iching 
) gen- 
g ap- 
ss of 
arent 
iants 
The quantities of extrinsic measure may be useful in 
some aspects. For example, in the case of recognizing hand- 
writing of digital numbers, the digits of “2” and “5” as 
well as “6” and “9” are similar in shape but different in 
orientation. With intrinsic measure alone, they can hardly 
be distinguished [Pavlidis, 1980]. Checking the rotation 
parameter of the extrinsic measure will be helpful in this 
case. Matching edges of a pair of stereo images [Schenk, Li 
and Toth, 1991], is another example. One of the edges in 
the left image may be similar in shape to more than one 
edge in the right image. In this case, the extrinsic measure 
provides a global criterion. 
In this study we match lines globally, that is, as whole 
entities. Consequently, lines which only match in parts can- 
not be dealt with. Since in many applications lines only 
match in parts, we are presently extending our approach to 
cope with this situation. 
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