Mars Colors

NASA has been concentrating on exploring and collecting data from Mars
instead of making pretty color photos, and as a result the color images
from Mars are not as nice as they could be at the moment. (I realize
NASA Mars teams will fix this over the next few months when they're not
snowed under working with the Rovers.)

The Rovers use 5 visible light filters for many of their images,
covering about half the visible light spectrum. If you assign RGB values
to each of these 5 and combine them, you get better results than picking
one for R, one for G, and one for B.

Here are most of the Rover images combined that way (at least the ones
with the 5 filter images available):

http://xpda.com/mars

Comments, criticism, and general harassment are welcome.

In a few months NASA should improve on this when they have time to
combine the Martian images with the data derived from the color calibration.

Bob Webster

Your photographs have a consistent "green" bias.

Your bias is better than the bias of Daniel Crotty
(http://www.lyle.org/~markoff/) that has a
consistent "blue" bias. He acknowledges that
however.

As far as color images go, the best I have ever
seen are the ones of Keith Laney
(http://www.keithlaney.com/index.htm)
He has NO bias and the images look extremely realistic.
Maybe too realistic, the color look too "earth" like.

It would be nice if you explained how did you do those
images and what software did you use

It would be nice if you explained how did you do those
images and what software did you use

I used Photo Mud (http://upperspace.com/photomud). The Color Merge
function lets you specify the RGB value for each of the 5 (or up to 10)
filtered images in the visible bands, and combine them into a single
color image. The RGB values I used are on the web page http://xpda.com/mars

I picked the RGB value for the filter wavelength color, and combined the
5 visible light images based on that. But it looked funny until I
lightened up the weights of filters L3 and L4. I think the infrared
filter L2 should be ignored for color composition, although some people
disagree.

There are problems with some or most uniformally converted images. I
have read that the different color filters may have different exposure
lengths for the same image, which would explain the occasional picture
with bright blue rocks. Even Keith Laney's pictures (while more "real"
looking than mine) have an almost black background to the stars of the
U.S. flag.

Well, looking at your work in more detail,
I find your colors almost true.

They are definitely better than http://www.lyle.org/~markoff/
judiging by your rendering of the Mars DVD.

http://xpda.com/mars/1P133065985ESF06GOP2542L-M1.jpeg

The original DVD photo (before launch) is:
http://www.redrovergoestomars.org/im...to_500x422.jpg

Keith Laney image is here
http://www.keithlaney.com/OCI/Image2.jpg

Yours may have a green bias, but I consider it more real
than Keith's too "earth" like colors.

Thanks for your work and for publishing it.

jacob

jacob navia wrote:
Yours may have a green bias, ...

I took care of most of the green bias today. Mars looks better!

http://xpda.com/mars

http://xpda.com/mars/pics

Bob

"Bob Webster" a écrit dans le message de
. ..
jacob navia wrote:
Yours may have a green bias, ...

I took care of most of the green bias today. Mars looks better!

http://xpda.com/mars

http://xpda.com/mars/pics

Bob

It surely does!

Thanks a lot for your work. I think yours are more realistic than the ones
of
Keith Laney. The colors of Keith are really too earth like, to good to be
true.

Yours look more convincing.

Thanks for making those images available

jacob