The seventh release of calibrated data is now online at the Mer Analyst Notebook/Geosciences; sols 450-540 -including Methuselah, the Whale pan, Jibsheet, Larry's Lookout and part of the Independence panorama.
Nico
Full Version: Mer Pds Release 7
I guess I know what I'm doing this weekend.
You bet. Some real nice locations in there... 
Nico
Nico
Good evening Nico !
Really enjoyed Your 'Horizons' panoramas ... I'll talk to You via e-mail later this weekend !
Once more congrats on a great job !
Philip
Really enjoyed Your 'Horizons' panoramas ... I'll talk to You via e-mail later this weekend !
Once more congrats on a great job !
Philip
View west on sol 538. Bonneville Crater visible with heatshild on rim. Also a dust devil track running across about halfway down from the horizon.
Click to view attachment
Click to view attachment
..and also the parachute is barely visible (see this enhancement).
Thanks, Alan!
Thanks, Alan!
New tau data from the latest PDS release: Spirit, Opportunity
The spike in the tau around Spirit sol 490 is making the skies look very muddled and the colors quite boring (even more than normal). I'll be adjusting the chromatic adaptation for this release to compensate, but that'll mean a couple more days of processing at least while I try to figure it out.
The good news is, there are a heaping helping of color in this release!
Spirit: 874 images, Opportunity: 645 images
The spike in the tau around Spirit sol 490 is making the skies look very muddled and the colors quite boring (even more than normal). I'll be adjusting the chromatic adaptation for this release to compensate, but that'll mean a couple more days of processing at least while I try to figure it out.
The good news is, there are a heaping helping of color in this release!
Spirit: 874 images, Opportunity: 645 images
I’ve finished up the color images from the most recent PDS release. They can be found at www.lyle.org/~markoff or in MMB (update:advanced update images:update images from:lyle.org). Because of changing conditions on Mars during this period of time, I had to adjust my processing to deal with a dominant hue overwhelming the scenes. Here’s a little bit of an explanation of what changed in this release.
As a part of my processing, I have been applying the CIECAM02 chromatic adaptation transform. This formula applies the white point of the source images to transform the image to the display white point. For this release, I've used a new source white point for each rover, one which better describes the way that our eyes would chromatically adapt to scene if we were there to see it ourselves.
The source white point I used for every previous release was based on the white and gray rings of a sundial shortly after landing. If complete loyalty to the perceptive model were the goal, the source white point should be different each day, even each time of day, but I chose to use just a single white point for all images. The hope is that changes in illumination would be discernable in comparisons of images taken under different conditions. If the chromatic adaptation were done perfectly for each individual image, then it would be harder to tell a dusty day from a clear one because the colors of the scene would be adjusted to remove such lighting effects. My hope was that by showing these changes, one could appreciate the images individually, with regards to the scene itself, and as a collection, to chronicle the changing conditions on Mars over the course of the mission.
Unfortunately, accomplishing both goals became difficult as the dust levels rose. Around sol 350, Opportunity's images started becoming dominated by a red/yellow hue, (assumedly due indirectly to rising dust level and its effect on sky brightness and color) While it may be interesting to look at these images and say "wow, it was getting dusty at this time in the mission", appreciating the content shown in the images was becoming increasingly hard since they were showing less hue variation.
This ‘reddening’ continued, for both rovers, on through this release as well. So, it seemed like a re-assessment of the source white point was in order. It’s hard to trust the calibration target this late into the mission for determining illumination. That would require knowing exactly how much dust has settled on its surface on a given sol. Instead, I used the content of the various scenes themselves to derive the source white point.
This method also allowed another issue to be addressed, which the original calibration target-derived white point did not. The traditional treatment of chromatic adaptation fundamentally attempts to adjust images so that illumination effects are removed (white reflectors are always white no matter what the lighting). Recent models try more specifically to maintain human perception from the scene to the display environment. In reality, our brains have no idea what the illumination of a scene actually is, nor do they know what objects are white reflectors. The content of the scene itself determines how our brains chromatically adapt. This means that a scene which is dominated by a single hue will cause our brains to chromatically adapt even under perfect lighting. Mars is the case in point for this distinction. On Earth, landscape scenes often contain a wide variety of hues, which makes the lighting the most important determinant in how our brains will adapt to the scene. On Mars, the color of the dust dominants every scene, indirectly in that the dust-laden sky is illuminating shadowed areas but also directly in that every way you could possibly look you will see the color of dust. So, by deriving the white point from the scenes themselves, I hope to better represent the actual perception of the scenes if we were there to see them ourselves.
As a part of my processing, I have been applying the CIECAM02 chromatic adaptation transform. This formula applies the white point of the source images to transform the image to the display white point. For this release, I've used a new source white point for each rover, one which better describes the way that our eyes would chromatically adapt to scene if we were there to see it ourselves.
The source white point I used for every previous release was based on the white and gray rings of a sundial shortly after landing. If complete loyalty to the perceptive model were the goal, the source white point should be different each day, even each time of day, but I chose to use just a single white point for all images. The hope is that changes in illumination would be discernable in comparisons of images taken under different conditions. If the chromatic adaptation were done perfectly for each individual image, then it would be harder to tell a dusty day from a clear one because the colors of the scene would be adjusted to remove such lighting effects. My hope was that by showing these changes, one could appreciate the images individually, with regards to the scene itself, and as a collection, to chronicle the changing conditions on Mars over the course of the mission.
Unfortunately, accomplishing both goals became difficult as the dust levels rose. Around sol 350, Opportunity's images started becoming dominated by a red/yellow hue, (assumedly due indirectly to rising dust level and its effect on sky brightness and color) While it may be interesting to look at these images and say "wow, it was getting dusty at this time in the mission", appreciating the content shown in the images was becoming increasingly hard since they were showing less hue variation.
This ‘reddening’ continued, for both rovers, on through this release as well. So, it seemed like a re-assessment of the source white point was in order. It’s hard to trust the calibration target this late into the mission for determining illumination. That would require knowing exactly how much dust has settled on its surface on a given sol. Instead, I used the content of the various scenes themselves to derive the source white point.
This method also allowed another issue to be addressed, which the original calibration target-derived white point did not. The traditional treatment of chromatic adaptation fundamentally attempts to adjust images so that illumination effects are removed (white reflectors are always white no matter what the lighting). Recent models try more specifically to maintain human perception from the scene to the display environment. In reality, our brains have no idea what the illumination of a scene actually is, nor do they know what objects are white reflectors. The content of the scene itself determines how our brains chromatically adapt. This means that a scene which is dominated by a single hue will cause our brains to chromatically adapt even under perfect lighting. Mars is the case in point for this distinction. On Earth, landscape scenes often contain a wide variety of hues, which makes the lighting the most important determinant in how our brains will adapt to the scene. On Mars, the color of the dust dominants every scene, indirectly in that the dust-laden sky is illuminating shadowed areas but also directly in that every way you could possibly look you will see the color of dust. So, by deriving the white point from the scenes themselves, I hope to better represent the actual perception of the scenes if we were there to see them ourselves.
Excellent, slinted, I'm watching them download right now.
Seconded - exxxxxxcelent (in a Mr Burns type way)
Doug
Doug
Superb-another 180 sols 
Just one question; regarding the inconsistency between older images apparent over sol441-460 of your galleries.
Would it be fair to consider an average for a range of sols between say sols 400-500 to allow for a smooth transition to the dusty conditions? Or are the new images due to the changes in white-point a big step ahead altogether in the true-color approximation?
Keep up the amazing work.
Nico
Just one question; regarding the inconsistency between older images apparent over sol441-460 of your galleries.Would it be fair to consider an average for a range of sols between say sols 400-500 to allow for a smooth transition to the dusty conditions? Or are the new images due to the changes in white-point a big step ahead altogether in the true-color approximation?
Keep up the amazing work.
Nico
Nix: I'm not sure yet how to handle that transition. Even now, I still picked one white point for the sol 451-540 range. When that becomes inappropriate, as my original selection did, then it'll be another harsh transition when a new one is needed.
My long-term goal is to come up with determination of white point based on tau and time of day, which would allow each image (or at least each sol) to have its own white point which would slowly transition the images as conditions get dustier. In answer to your last question, yes, I do feel that an image-based white point conversion is a closer approximation of true color compared to what I was doing before, so I would like to find a way to reprocess the older images with this in mind.
My long-term goal is to come up with determination of white point based on tau and time of day, which would allow each image (or at least each sol) to have its own white point which would slowly transition the images as conditions get dustier. In answer to your last question, yes, I do feel that an image-based white point conversion is a closer approximation of true color compared to what I was doing before, so I would like to find a way to reprocess the older images with this in mind.
hmmm..I see. I look forward to a reprocessing once you get it figured out!
Your Long-term goal sounds promising
Nico
Your Long-term goal sounds promising
Nico
QUOTE (slinted @ Feb 11 2006, 07:58 PM)
My long-term goal is to come up with determination of white point based on tau and time of day, which would allow each image (or at least each sol) to have its own white point which would slowly transition the images as conditions get dustier.
If it's of any use I can give you reasonably good approximations for instantaneous insolation based on sol, time of day and tau.
So how much MER data do you all have now? ... and what are you storing it on?
I've posted updated mmb pans with slinted's calibrated color. I'm still looking through them all, but there's a bunch of good stuff in there, especially for Spirit. Here's a couple screenshots:
Now I'm going to go back and see if I can add titles to the more significant pans from 450-540. Plus I want to grab screenshots of all of Spirit's sunset views (there are several of them!).
Now I'm going to go back and see if I can add titles to the more significant pans from 450-540. Plus I want to grab screenshots of all of Spirit's sunset views (there are several of them!).
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