Galileo images and mosaics of Europa |
Galileo images and mosaics of Europa |
Aug 22 2005, 04:03 AM
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#1
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Interplanetary Dumpster Diver Group: Admin Posts: 4404 Joined: 17-February 04 From: Powell, TN Member No.: 33 |
I have worked on sprucing up some global views of Europa from Galileo. There are a few more global views I hope to get to eventually. But the best two at nearly full phase benefited a lot.
[Moderator note: There are several more threads containing Galileo Europa images but they all contain several inactive image links. The main threads are: http://www.unmannedspaceflight.com/index.php?showtopic=2016 http://www.unmannedspaceflight.com/index.php?showtopic=2174 http://www.unmannedspaceflight.com/index.php?showtopic=2222 http://www.unmannedspaceflight.com/index.php?showtopic=2082 http://www.unmannedspaceflight.com/index.php?showtopic=2142 ] -------------------- |
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Aug 23 2005, 12:37 AM
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#2
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Senior Member Group: Members Posts: 1276 Joined: 25-November 04 Member No.: 114 |
Keep them coming! Europa really deserves an orbiter.
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Aug 23 2005, 03:07 AM
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#3
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Interplanetary Dumpster Diver Group: Admin Posts: 4404 Joined: 17-February 04 From: Powell, TN Member No.: 33 |
QUOTE (Decepticon @ Aug 23 2005, 12:37 AM) Well, I might work on some other moons, or try some mosaics. This is the only other global view of Europa I could find in the Galileo set that was worth combining with some color data. -------------------- |
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Aug 23 2005, 11:14 AM
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#4
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IMG to PNG GOD Group: Moderator Posts: 2251 Joined: 19-February 04 From: Near fire and ice Member No.: 38 |
Regarding my Europa map, the color there was taken from global Voyager images only. I used these to colorize higher resolution grayscale data (mainly clear filter). The reason I used Voyager and not Galileo data was higher resolution and IIRC Galileo had not imaged Europa globally in color at the time I made the map. I don't remember whether I used OGB or OGV (probably the latter) - I'm at work and can't check it now.
I'm pretty sure the color is a bit too saturated in my map. It may too reddish as well, a common problem when the wavelength of the data used for colorizing is too short (e.g. O instead of R and/or V instead of B ). I have been working on a much bigger Europa map (9000+ pixels in the horizontal direction) from time to time for more than two years. I have reprojected most of the high-res data I plan to use but haven't started working on the color. I plan to use Galileo images for color where possible, filling gaps (or very low-res areas) with Voyager data and/or synthetic color. I also expect to use synthetic B instead of V. The V images are more contrasty than the B images but mixing G and V should give a fairly good results (definitely better than using V only). One thing that complicates color work is Europa's photometric properties, limb darkening varies with wavelength and I prefer images as close to zero phase angle as possible. Ted's images look fairly good, especially wrt sharpness but there are some saturation problems, caused both by saturation in the red images (this manifests itself as pinkish areas) and in all of the images in some cases (bright, white areas). I have some early 'test images' of Europa that look similar. And I should add that there is great color data at 1.4 km/pixel in the E14 data. BTW Europa's color should be kid's stuff compared to Io. There is some information on Io's color on my experimental renderings page ( http://www.mmedia.is/bjj/3dtest/ ) and I will add more once I make my new map of Io available, I've been too swamped in data recently to update my website . In particular, it is impossible to use 'unmodified' IR7560 as red without seriously messing up the color balance. |
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