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Unmanned Spaceflight.com > Mars & Missions > Past and Future > MER > Tech, General and Imagery
edstrick
The currently posted Spirit Pancam panoramas being taken at Larry's Lookout so far have only L1 (infrared) and L5 (red) filter bands (plus R2 and R7). If band L7 (violet-UV) have been taken, they apparently have not been downlinked yet.

With only 2 spectral channels, it's impossible to get true-color images, but cosmetically acceptible images can be generated by averaging the long wavelength band (L2) and the short wavelength band (L5, in this case) as a "pseudo-middle-wavelength" band. Then generate a color image using L1, Average, L5 as Red, Green, Blue bands, respectively.

In Photoshop 4.0 (menus will vary with other editions and you can't do it with Photoshop-Eviscerated .... I mean Photoshop-Elements.... a shorthand for the image processing/generation sequence is as follows. Note: I'll shorten the input image names to "L2"and "L5", and leave out all the more or less obvious "OK" responses and the like.

File > Open > "L2"
File > Open > "L5"

Window > Tile
Image > Mode > Grayscale
(select/click on the other image)
Image > Mode >Grayscale
(JPL's raw jpgs are RGB, even though there is no color data)

Image > Calculations
Source 1 > "L2"
Source 2 > "L5"
Blending > Normal"
Opacity > 50%
Result > NEW

Image > Mode > Grayscale

Window > Show > Channels (if that tool isn't already onscreen)
">" (click on the right-arrow to get the channel menu)
Merge Channels
RGB Color

Red: "L2"
Green: "Untitled-1"
Blue: "L5"

File > Save
For the filename, I pick the shortwavelength file's name, and append the filter numbers: band2filename_25.jpg

I'll often Image > Adjust >Levels or Image > Adjust > Curves to get better brightness distributions, run Filter > Sharpen > Sharpen to crisp up the image, and, and on screwball filter combinations like these, I may boost color saturation
with Image > Adjust > Hue/Saturation before saving the file.
edstrick
Attached to the previous post is a 2-color image looking approximately southeast up Husband Hill from Larry's Lookout. The image color and contrasts have been optimized to show the range of color variety in the data, not to approximate "true-color" from the IR and Red bands. The sky appears blue because it is *LESS RED* than anything else in the image.

Attached to this posting is a 2-color view of rocks with what I'm calling "Popcorn" weathering next to the rover.
edstrick
This is a 2-color view (L2 and L5) looking out across the Gusev lava plain more or less to the west-northwest or northwest. Rover tracks expose less-red soils, probably with a basaltic sand component or the grayish local rock, whatever THAT is.

As before, no attempt is being made to generate "true-color", the intent is to provide maximum "discernability" of geologic detail.
edstrick
Last, for now, is a picture looking a bit east of north in the valley between Husband Hill and the hill to the north. The variety of dunes/drifts and other eolian features in the smoother wind-blown and eroded "stuff" in the valley and on the floor of the hollow/crater the rover is looking down into from Larry's Lookout (I keep thinking Larry's Leap... oops!) is fascination.

On the previous post, looking northwest, the linear dune/drift across the right half of the image is pretty impressive.
edstrick
ACK... forgot to attach the pic to the last post.

(How do I get the pic visible in the post, instead of just the link to the pic?)
djellison
You cant - you need to upload to your own webspace if you want to do that.

Doug
aldo12xu
Thanks for the detailed instructions edstrick. It's most helpful. I'll try to play with some images this weekend.
erwan
QUOTE (edstrick @ Mar 5 2005, 04:15 AM)
(How do I get the pic visible in the post, instead of just the link to the pic?)


Edstrick: you may use file hosting websites: upload your images on a distant website, then link your uploaded images on the forum. Please look for examples on the adresses your browser go when you click on visible thumbs or images...
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