[Freegis-list] re: Mars multi spectral images

[Mark Coletti]

> Message: 1
> From: "G. Orme" <mymail at harmakhis.org>
> Date: Fri, 6 Dec 2002 13:36:01 +1000

> Actually yes. It is a puzzling controversy. 

  It is.  Regardless of who is right, it'll be very interesting outcome.

> In some ways the image in question seems to be a degraded copy of
> the so called original NASA one, but nobody has been able to
> duplicate it.

  Actually the Enterprise version seems to be _better_ than the
  "official" UoA one.  I think there was speculation that the version
  that Laney got was an average of more than one IR image, thus
  cancelling out some noise.

> The Enterprise photo looks like it has compression artifacts in it
> that look like buildings but no combination of effects so far has
> come up with them.

  I've seen compression artifacts before, and those do not look like
  compression artifacts.  Compression artifacts do not _add_
  information; rather they tend to blur features, with the blurring in
  proportion to the feature frequency.  (Frequency, as in how many
  pixel changes occur over a certain area.  So a patch of fields has a
  lower frequency than, say an urban area.)  These things have sharply
  defined edges, which is not something you'd see with compression
  artifacts.

  Then again, it could be somebody playing silly buggers with
  Photoshop.

For those that care, you can surf to
http://www.enterprisemission.com/ir_images.htmlhttp://www.enterprisemission.com/ir_images.html
for more info.

Cheers!

Mark
-- 
Mark Coletti | mailto:mcoletti at lychnobite.org | http://www.lychnobite.org/
    My software never has bugs. It just develops random features.