Posted: Fri Mar 18, 2005 9:34 am Post subject: can this be done in photoshop?
I cant seem to pull off the technique in PS7. Here's the discription to colorize a picture. anyone know if PS7 can do this?
JB
The letter I have with the step by step:
(The process is simple. Locate three frames in the raw data that show
the same image- you are probably familiar with that part of the process.
Looking at the end of the filename, and using panoramic data only, you will
see L2, L4, L5, or similar designations at the end of the filenames.
For the best and most accurate images, you need L4, L5, and L6 images.
The L4 image should be edited so that it shows only the red spectrum.
All blue and green data should be removed. This will be the red frame.
The L5 image should be edited to remove all red and blue data, resulting
in a pure green frame.
The L6 image should be edited to remove all red and green data,
resulting in a pure blue frame.
If there is any white or any color other than the primary red, green or
blue that belongs in the frame, the process is not correct. There are
different options for altering color on different photo editors, and I am
not familiar with Photoshop itself or how it operates.
Now, in the finished image, each frame will contribute 1/3 of the
overall color. Any two frames are 1/2 of the color each. If you can
combine all three frames at once, then each should be of equal "weight". If
you have a "stitch" option on you editor that allows only two frames at a
time, then set transparency at 50% and combine any two frames, and save this
partial result. Then set transparency to 67% and overlay the third frame.
In any process, each color separation should be weighted equally. Try
this with the calibration MarsDial images first to get a little practice.
They tend to need exactly the same values for all three frames.
For other images, the percentages will change based on the relative
intensity of each color. A good way to figure these out is called
"densitometry". If you have assembled a MarsDial image and can see the
ground in it, you can use the percentages of each color in the soil, rocks,
and other materials to guide you in working out the percentages. If you do
not have these pieces of data, you can make acceptable images by assuming
100% red, 60% green, and 30% blue if you are looking at the ground.
There are no hard and fast rules, because NASA threw away the relative
intensity data, but once you start assembling the images, you will quickly
spot how to balance the color properly. It also helps to have hardware on
hand that matches the colors on the rovers, such as blue heat-shrink tubing
used on the wiring or orange Kapton plastic used to wrap the cables.)
Joined: 05 Mar 2003
Posts: 3987
Location: Cheltenham, UK
Posted: Sat Mar 19, 2005 6:09 am Post subject:
It's basically just a channels exercise. The article asks you to remove/discard certain of the RGB channels in each of the pictures, and to then amalgamate the results in to one image. Then the transparancy of the individual coloured layers is altered to produce colour. _________________ If life serves you lemons, make lemonade!
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