Since the first PDS release came out, I've been struggling with the best way to display calibrated 3 filter color, especially those with the L2 as red. Most methods can create an internally consistent looking image from a particular 3 filter set, but don't quite match other filter sets of the same target. I recently started in on a new attempt, one which almost completely abandons all color theory and replaces it with a treatment the images strictly as numeric data. Taking the first 180 sols of 6 filter imagery as a training set, I use a least squares fit to come up with formula for each 3 filter combo which best reproduces the XYZ values calculated from the more accurate 6 filter fit. I knew up front this was a bit of a kludge, but was pleasantly surprised at the consistency it produced.

As an example of this new method, I've posted up an update to my site. The calibrated galleries now include ...all... the 3 filter (256,257,456,457,247) as well as 6 filter images from the first 180 sols, weighing in at a hefty 1598 color images from Opportunity, and 1741 from Spirit.

A more complete description of the methods used can be found here

Also, I feel it appropriate to mention here of all places, my images are very bland and aesthetically boring in comparison to the tremendous efforts put forth in this forum and by JPL. My goal has always been consistency and comparability. As we know from working with the stretched raw images, changes in the scale of brightness can cause major consistency problems when looking at two images side by side. With that in mind, no local or 'by image' contrast adjustments have been made, almost all images appear in the same scale of brightness.

I love it, Dan! 3300+ images at near true colours. awesome. I imagine a lot of the forum users have access to some form of photo program that would allow adjustments to brightness and contrast, so that's not a big factor for me. Is it possible to apply your technique to the raw images beyond sol 180?

Scanning through the new images, I was wondering about getting colours from the right filtered images. Is it possible to generate right stereo images that would approximate the colour of the left images. For instance, if it's not too much trouble , what kind of right image would you be able to generate for this Opportunity photo from sol 168:

http://www.lyle.org/~markoff/pds/234567/1P...97L234567C1.JPG

Aldo: Thanks!
Since the 3 filter equations are trained on the calibrated data, they end up being very dependant on specific values of the input images. It would be necessary to, at the very least, remove exposure length from the images for each frame by hand before putting them in. And, while many people here that produce great color from the raws have eye and skill for this, I unfortunately do not. When the narrow expected brightness ranges of the calibrated files are replaced with the wildly varied stretches of raw images...lets just some bizarre looking stuff comes out.

As to the right frame images, I think this could potentially work very well for properly coloring them, as training good equations wouldn't require that the right images actually correspond to any visible color. The fitting could match the "signal" of a given object in near infrared with its corresponding visible color. The difficulty for me putting something like that together is matching pixel for pixel the right and left frames for the whole dataset for training purposes. It isn't necessary to match them up to the left frames to colorize them once the equations are trained, but would need it to get the equations in the first place. If I could do that programmatically, then it would probably work.

I'll second that without hesitation. Your site is fantastic slinted, providing a solid basis for color comparison between sols and rovers. Brightness and contrast we can change ourselves, what is important is to have a trusted source like you for colors. Thanks !

It is top-level your new galleries! We are all gratefull for your work.
I've been wondering too for a way to generate the right R1-2 frames with consistency to the left calibrated ones. For colorizing the right frames I use an average of the L2-3-4 wavelengths to RGBcolor converted for R2 and an average of L6-7 for R1. I then blend the layers which gives me green, copy the green and paste it in between, all in PS.

Nico

This is a stereo for your sol 168 Oppy image Aldo. It's one of my favorites!
Razor Edges or so it was called right?

You know, I reckon they got it all wrong, talking about concretions and all that water-related stuff - it's the fossil of a T-Rex skull, lying on it's side. There! That explains *everything*!

Seriously, though, those razor edges look so fragile - I wonder how long they actually last, exposed to air like that, and whether the surface is actually quite dynamic over even a short period of time. Perhaps the extended extended extended mission could involve a u-turn and retracing of tracks back to the lander, just to see what changes there have been. Of course, that'd have to be after a decent interval, say about 2010...

The calibrated galleries are now updated to include the sol 181-270 PDS release.

Great job, NIX! The razorbacks are one of my favourite features as well.