On Tue, Aug 14, 2007 at 04:55:56PM +0100, Emanuele D'Arrigo wrote:
Actual per-pixel subtraction gives
interesting-looking
results if the difference is large enough, but they can be
sometimes difficult to relate to the original images and
subtle changes will be difficult to spot due to their low
contrast. Also, given a 0 to 255 range in value for each pixel,
the result of a subtraction operation would be in the range
-255 to +255. This then needs to be compressed back
into a displayable 0 to 255 which effectively loses half
of the information.
What about that new thing that guy showed off last week on a slashdot
piece with the modified JPEGs of Al Q'aeda? Is that pertinent here?
Cheers,
-- jra
--
Jay R. Ashworth Baylink jra(a)baylink.com
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