Example
If we consider
three images shwon in
Fig. 3.3 and their absolute differences depicted in Fig.
3.4. The
Euclidean distance between any two of the three patterns
is the same, namely . However,
we can see that image A
is more similar to image B than
it is to image C. This
illustrates that the Euclidean distance may not be
appropriate to characterize the similarity among images since
it does not take into account the spatial
information.