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Galileo images and mosaics of Europa
Bjorn Jonsson
post Nov 1 2011, 12:16 AM
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Wow, this looks awesome, both the images/mosaics and stereograms. Do you have any idea of how accurate the stereograms are? At least they look realistic.

I have now 'discovered' that there actually is stereo coverage of Conamara Chaos but unfortunately it's not the very hi-res E12 stuff - it's E6 images from ~19000 and ~6600 km. I'll run it through my stereo software one day but I don't know when - I have a big 'queue' of close to one thousand (!) images I want to run through stereo and/or shape from shading software. Doing shape from shading might be interesting as well but a possible problem there is albedo variations. Regarding the E12 images I suspect the viewing geometry for the adjacent, partially overlapping images in the E12 mosaic is too similar for stereo but I'm going to check it.

And finally let's not forget this great stuff from Paul Schenk:

http://stereomoons.blogspot.com/2009/09/br...mara-chaos.html
http://www.youtube.com/watch?v=4N6UmW3yh1A
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machi
post Nov 1 2011, 05:39 AM
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Thanks,
Accuracy of the stereograms Fig.5 and Fig.6 is dependent on the precision of my eyes and my experience.
Stereograms are made by warping in Sqirlz Morph using manually added control points. With these images, I achieved my personal record - more than 1800 control points.

"I have now 'discovered' that there actually is stereo coverage of Conamara Chaos but unfortunately it's not the very hi-res E12 stuff - it's E6 images from ~19000 and ~6600 km."

I used image, 7513R from orbit E6. This image covers whole mosaic, so theoretically whole mosaic can be done in stereo with similar results to Fig.5/6.

"And finally let's not forget this great stuff from Paul Schenk:"

Yes, I know his masterful work, after all Paul Schenk is guru of DEM models. This is reason why I'm doing stereograms and not DEMs. smile.gif

I made little comparison, with similar geometry, between stereogram from two images with ~same resolution (1900 and 1913 from orbit E12, Fig.3) and
manually warped version (Fig.5), so you can judge both versions. Fig.3 is right image and Fig.5 is left image.
Attached thumbnail(s)
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ElkGroveDan
post Nov 1 2011, 01:19 PM
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QUOTE (machi @ Oct 31 2011, 10:39 PM) *
With these images, I achieved my personal record - more than 1800 control points.

I think I would go blind.


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machi
post Nov 1 2011, 05:53 PM
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I'm pleased, that someone has clue, how painful job this is. biggrin.gif


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jasedm
post Nov 1 2011, 06:30 PM
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Your pain is our gain!

Awesome, thanks.
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tedstryk
post May 3 2012, 04:42 PM
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To celebrate the selection of JUICE, I have a new Galileo Europa post up on my blog.


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Bjorn Jonsson
post May 5 2012, 01:40 PM
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Very nice image that initially confused me a lot since I'm familiar with all of the Galileo global color coverage of Europa (or so I think). When I read where the color is from things became more clear.
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tedstryk
post May 6 2012, 06:02 PM
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QUOTE (Bjorn Jonsson @ May 5 2012, 02:40 PM) *
Very nice image that initially confused me a lot since I'm familiar with all of the Galileo global color coverage of Europa (or so I think). When I read where the color is from things became more clear.


It is of course very approximate since the color data comes from very different illumination conditions. When it comes to Galileo data, one is often forced to really push things. I've tried for years to make a good fit for this, and it required fiddling with the gamma in the image and with a bit of filtering to compensate for the luminosity being based entirely on a violet filter image. This is the first version that didn't look to badly "off." Here is another version, on that might be my favorite, that is aesthetically slightly better.

Attached Image


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nprev
post May 6 2012, 06:43 PM
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And there's my new desktop. Thanks, Ted!


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tedstryk
post May 6 2012, 07:13 PM
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Your welcome...now if Juno and JUICE would hurry up rolleyes.gif


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tedstryk
post May 6 2012, 08:23 PM
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I should add that I removed noise by hand. There was a lot of noise in the image, but no automated removal did a good job removing it without wrecking havoc on the little ridges.


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machi
post May 8 2012, 11:05 PM
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Beautiful image, Ted!

It is from orbit E17, isn't it?

BTW, for JUICE is planned NAC camera with 5 microrad resolution.
With this camera, JUICE will obtain two times better images of Europa even from the orbit around Ganymede (and with many filters).


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tedstryk
post May 9 2012, 12:29 AM
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QUOTE (machi @ May 8 2012, 11:05 PM) *
Beautiful image, Ted!

It is from orbit E17, isn't it?

BTW, for JUICE is planned NAC camera with 5 microrad resolution.
With this camera, JUICE will obtain two times better images of Europa even from the orbit around Ganymede (and with many filters).

Yes, that's it. Thanks. Trying to turn that violet image into a good "gray" image was a pain. I have made several previous attempts that were much less successful.
Wow, I hadn't read the specifications. Looking at the time this was taken, soon afterwards Europa transited Jupiter. Had Galileo had a working antenna, it would have made for one of the most spectacular movies ever.


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Bjorn Jonsson
post Mar 12 2013, 12:39 AM
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This is a mosaic of the Galileo I25 Europa images:

Attached Image


The 12 images comprising the mosaic were obtained on November 25, 1999 at a distance of 96000 km from Europa. This is the only good global coverage of Europa's Jupiter facing hemisphere. For aesthetic purposes I filled some narrow horizontal gaps by cloning nearby data.

For many years I have wanted to do something with the Europa images but didn't, mainly because a new mission that can image Europa at high resolution didn't seem that far in the future (a decade or so until Jupiter arrival isn't that much in this context). But now I have given up waiting - by now it has become pretty clear that nothing of significance is going to happen until almost 20 years from now when JUICE arrives at Jupiter. The good thing though is that this mission seems very likely to actually happen - more likely than previous mission concepts ever have been.

Because of this long time until the next spacecraft that can obtain hi-res images of Europa arrives I decided to start work on a 16384x8192 pixel global map of Europa using all of the useful Galileo and Voyager images. This mosaic is a 'by-product' from that project.

Interestingly the only mosaic I have found from the I25 data is only 900x900 pixels and has obvious seams since the brightness of the original images is variable:

http://photojournal.jpl.nasa.gov/catalog/PIA02528
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tedstryk
post Mar 12 2013, 12:50 AM
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Great work! Oh, and I for some reason thought that this mosaic was much more spotty than this...wheels are turning in my head...


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