[Spambayes] Inspecting images (was: SpamBayes to Handle Embedded Images)

[wsy]

   From: Vincent Zweije <vincent+spambayes at zweije.nl.eu.org>

   [...]

   Say, how do those photocopy machines decide and refuse when a bank note
   is being copied?

There's a five-circles "constellation" that means "this is currency,
do not copy".  It's the ratios of the distances that matter, not the
orientation, so spinning the note (or the design) around won't change
anything.

In Euro notes, it's the little H-shaped constellations, with little 
circles at the tips.  

In US money, (only in the 20's and up so far, but will be inserted in
lower bills as they are redesigned) it's in the dollar numbers
themselves.  Look on a 20; you'll see a field of -many- "20" texts
scattered sorta randomly.  It's not random.  The position of the 0's
form the same "constellation" as is obvious on the EU notes.

   -Bill Yerazunis