[APML] OT: "True Color" Mars Mosaic

[Chuck Vaughn <aa6g@aa6g.org>]

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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