Re: [APML] OT: "True Color" Mars Mosaic

[Jeff Allen <jeffstak@yahoo.com>]

Great job Chuck!
I'm also interested in what will be said about the
apparently two different layers of rock in the
outcrop. The lower one looks darker and finely layered
(shallow water deposits?)while the upper more exposed
rocks look more massive and uniform and
lighter(volcanic or maybe aeolian?).
Jeff Allen

--- Chuck Vaughn <aa6g@aa6g.org> wrote:
> List,
> 
> Here's my best guess at what the outcrop at the
> Opportunity site really 
> looks like.
> 
> http://www.goldrush.com/~aa6g/Images/outcrop_cal.jpg
>  (450KB)
> 
> Here's what was done:
> 
> 1) Assembled a tricolor with rover solar panels in
> the image and 
> calibrated the image so that the panels were neutral
> dark gray. They 
> look black in every photo we've seen so I assume
> that is correct. 
> Here's that image:
> 
>
http://www.goldrush.com/~aa6g/Images/soil_calibration.jpg
>  (115KB)
> 
> 2) Sampled the soil to get the hue and saturation.
> If you don't get 
> these close the color will be way off.
> 
> 3) There's a bounce mark in the lower left corner of
> the outcrop image. 
> The JPL scientists have said that bounce marks are
> revealing the soil 
> under the hematite. They also said the hematite
> concentration is 
> extremely low where the rover is sitting. So I made
> a leap of faith and 
> said the soil at the rover is the same color as the
> soil under the 
> bounce mark. So the first image on the left was
> adjusted as such.
> 
> 4) Successive images were adjusted to match the
> first.
> 
> 5) The resulting sky was blotchy mess of oranges and
> pinks because the 
> original images have slight vignetting and adjusting
> the green and blue 
> channels accentuates the problem. So I chose  a
> representative sky 
> color at the horizon and at the top of the image and
> used the Photoshop 
> Gradient tool to create an even sky that becomes
> less orange as you go 
> up.
> 
> 6) Desaturated any blue rocks.
> 
> Maybe someday NASA will get around to making their
> own and I'll see how 
> close I got. The plains in the background do remind
> me of the those 
> large dark areas in images of Mars from Earth.
> 
> Enjoy!
> 
> Chuck
> 
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