APOD: Stereo Phobos (2022 Aug 06)

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APOD: Stereo Phobos (2022 Aug 06)

Post by APOD Robot » Sat Aug 06, 2022 4:05 am

Image Stereo Phobos

Explanation: Get out your red/blue glasses and float next to Phobos, grooved moon of Mars! Captured in 2004 by the High Resolution Stereo Camera on board ESA's Mars Express spacecraft, the image data was recorded at a distance of about 200 kilometers from the martian moon. This tantalizing stereo anaglyph view shows the Mars-facing side of Phobos. It highlights the asteroid-like moon's cratered and grooved surface. Up to hundreds of meters wide, the mysterious grooves may be related to the impact that created Stickney crater, the large crater at the left. Stickney crater is about 10 kilometers across, while Phobos itself is only around 27 kilometers across at its widest point.

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Re: APOD: Stereo Phobos (2022 Aug 06)

Post by orin stepanek » Sat Aug 06, 2022 12:48 pm

Phobos_stereoME_1024c.jpg
stereo photo of Phobos
PSP_007769_9010_IRB_Stickney1024.jpg
I like the orange and blue coloration of Phobos! Kinda reminds me of
iron & steel! :shock:
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Re: APOD: Stereo Phobos (2022 Aug 06)

Post by SeedsofEarfth » Sat Aug 06, 2022 6:34 pm

I wonder why Nasa doesn;t use the same technology as Facebook to produce stereo or 3-D pictures. How many people have an old set of red and blue paper spectacles lying around?

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Re: APOD: Stereo Phobos (2022 Aug 06)

Post by johnnydeep » Sat Aug 06, 2022 8:55 pm

SeedsofEarfth wrote: Sat Aug 06, 2022 6:34 pm I wonder why Nasa doesn;t use the same technology as Facebook to produce stereo or 3-D pictures. How many people have an old set of red and blue paper spectacles lying around?
So how does Facebook do it?
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Re: APOD: Stereo Phobos (2022 Aug 06)

Post by silvio.olivier@videotron.ca » Sat Aug 06, 2022 9:05 pm

Is Phobos formed by sedmentary rock ? The parallel paterne is stricking. Thank you!

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Re: APOD: Stereo Phobos (2022 Aug 06)

Post by johnnydeep » Sat Aug 06, 2022 9:06 pm

Wow. The "mysterious grooves" link describes some pretty wild behavior of the "rolling boulders", predicted by computer models of the theory put forth to explain all the large grooves on Phobos, and purportedly resulting from the impact that created Stickney crater.
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Re: APOD: Stereo Phobos (2022 Aug 06)

Post by johnnydeep » Sat Aug 06, 2022 9:07 pm

silvio.olivier@videotron.ca wrote: Sat Aug 06, 2022 9:05 pm Is Phobos formed by sedmentary rock ? The parallel paterne is stricking. Thank you!
Nope, not sediments, but rolling rocks! See the "mysterious grooves" link in the description.
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Re: APOD: Stereo Phobos (2022 Aug 06)

Post by MarkBour » Sat Aug 06, 2022 9:16 pm

SeedsofEarfth wrote: Sat Aug 06, 2022 6:34 pm I wonder why Nasa doesn;t use the same technology as Facebook to produce stereo or 3-D pictures. How many people have an old set of red and blue paper spectacles lying around?
Phobos again!

I really like the 3D model at the APOD caption's link: asteroid-like moon's.
(Scroll down to the second image, which is wonderfully interactive).

Clearly, Phobos has had an exciting past. So many of the craters are in line with one another, and then some of them are basically a solid line (curve). I'm not saying that the scratch-like lines on Phobos were created by sets of impacts, but there certainly is a whole spectrum up to the lines. In some cases, I counted over 50 small craters in a row.

I'm not persuaded by the study that produced the theory that some of the tracks were made by boulders bouncing along. One wonders what would have finally become of the alleged boulders. I wonder if Phobos passed through Saturn's rings, or a very high-population region of the asteroid belt, or a comet's tail or two on its way to Mars. Really, I haven't seen or thought of a theory of the origin of the tracks that is satisfying. Which is why they're so interesting!

The leading theory of the origin for Phobos and Deimos is that they are captured asteroids. According to Wikipedia, this theory is not without problems.
https://en.wikipedia.org/wiki/Mars
But both have circular orbits, near the equator, which is unusual for captured objects and the required capture dynamics are complex.
It'll all make a lot more sense when we locate the door in one of the darker craters. :-P
Mark Goldfain

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Re: APOD: Stereo Phobos (2022 Aug 06)

Post by Chris Peterson » Sat Aug 06, 2022 10:41 pm

MarkBour wrote: Sat Aug 06, 2022 9:16 pm
SeedsofEarfth wrote: Sat Aug 06, 2022 6:34 pm I wonder why Nasa doesn;t use the same technology as Facebook to produce stereo or 3-D pictures. How many people have an old set of red and blue paper spectacles lying around?
I'm not persuaded by the study that produced the theory that some of the tracks were made by boulders bouncing along. One wonders what would have finally become of the alleged boulders. I wonder if Phobos passed through Saturn's rings, or a very high-population region of the asteroid belt, or a comet's tail or two on its way to Mars.
Saturn's rings are made up mostly of ice particles smaller than boulders. But had Phobos passed through the rings, we'd have craters, not streaks. A comet's tail is just dust and gas. Anything big enough to mar the surface would be very, very rare and would also produce a crater. Bodies in the asteroid belt are not densely spaced. You could sail around in the asteroid belt for thousands of years and never see one.
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Re: APOD: Stereo Phobos (2022 Aug 06)

Post by Chris Peterson » Sat Aug 06, 2022 10:49 pm

SeedsofEarfth wrote: Sat Aug 06, 2022 6:34 pm I wonder why Nasa doesn;t use the same technology as Facebook to produce stereo or 3-D pictures. How many people have an old set of red and blue paper spectacles lying around?
I don't know what FB does, but here's a de-anaglyphed version suitable for cross-eyed viewing.
_
de-anaglyph-Phobos_stereoME_800.jpg
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Re: APOD: Stereo Phobos (2022 Aug 06)

Post by MarkBour » Sun Aug 07, 2022 12:29 am

Chris Peterson wrote: Sat Aug 06, 2022 10:41 pm
MarkBour wrote: Sat Aug 06, 2022 9:16 pm
SeedsofEarfth wrote: Sat Aug 06, 2022 6:34 pm I wonder why Nasa doesn;t use the same technology as Facebook to produce stereo or 3-D pictures. How many people have an old set of red and blue paper spectacles lying around?
I'm not persuaded by the study that produced the theory that some of the tracks were made by boulders bouncing along. One wonders what would have finally become of the alleged boulders. I wonder if Phobos passed through Saturn's rings, or a very high-population region of the asteroid belt, or a comet's tail or two on its way to Mars.
Saturn's rings are made up mostly of ice particles smaller than boulders. But had Phobos passed through the rings, we'd have craters, not streaks. A comet's tail is just dust and gas. Anything big enough to mar the surface would be very, very rare and would also produce a crater. Bodies in the asteroid belt are not densely spaced. You could sail around in the asteroid belt for thousands of years and never see one.
Good points, as always. So, do you find one of the popular theories believable, or none of them very much?
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Re: APOD: Stereo Phobos (2022 Aug 06)

Post by Igwasborn » Sun Aug 07, 2022 1:37 am

Very interesting even maybe only real if in our face our eyes were 12? km apart.

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Re: APOD: Stereo Phobos (2022 Aug 06)

Post by Chris Peterson » Sun Aug 07, 2022 5:26 am

MarkBour wrote: Sun Aug 07, 2022 12:29 am
Chris Peterson wrote: Sat Aug 06, 2022 10:41 pm
MarkBour wrote: Sat Aug 06, 2022 9:16 pm

I'm not persuaded by the study that produced the theory that some of the tracks were made by boulders bouncing along. One wonders what would have finally become of the alleged boulders. I wonder if Phobos passed through Saturn's rings, or a very high-population region of the asteroid belt, or a comet's tail or two on its way to Mars.
Saturn's rings are made up mostly of ice particles smaller than boulders. But had Phobos passed through the rings, we'd have craters, not streaks. A comet's tail is just dust and gas. Anything big enough to mar the surface would be very, very rare and would also produce a crater. Bodies in the asteroid belt are not densely spaced. You could sail around in the asteroid belt for thousands of years and never see one.
Good points, as always. So, do you find one of the popular theories believable, or none of them very much?
It's not something I've looked closely at. But tracks from rolling boulders doesn't sound unreasonable. Or maybe some kind of distortion from the tidal forces acting on the rubble pile.
Chris

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Re: APOD: Stereo Phobos (2022 Aug 06)

Post by XgeoX » Sun Aug 07, 2022 7:57 am

Chris Peterson wrote: Sat Aug 06, 2022 10:49 pm
SeedsofEarfth wrote: Sat Aug 06, 2022 6:34 pm I wonder why Nasa doesn;t use the same technology as Facebook to produce stereo or 3-D pictures. How many people have an old set of red and blue paper spectacles lying around?
I don't know what FB does, but here's a de-anaglyphed version suitable for cross-eyed viewing.
_
de-anaglyph-Phobos_stereoME_800.jpg
Thanks Chris, cross eyed viewing is my favorite.
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Re: APOD: Stereo Phobos (2022 Aug 06)

Post by XgeoX » Sun Aug 07, 2022 7:59 am

SeedsofEarfth wrote: Sat Aug 06, 2022 6:34 pm I wonder why Nasa doesn;t use the same technology as Facebook to produce stereo or 3-D pictures. How many people have an old set of red and blue paper spectacles lying around?
I actually bought a couple of nice pairs on ebay to keep handy. I’ve ben dying to find a pair made of real glass but no luck so far.

Eric
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Re: APOD: Stereo Phobos (2022 Aug 06)

Post by Ann » Sun Aug 07, 2022 8:00 am

MarkBour wrote: Sat Aug 06, 2022 9:16 pm
SeedsofEarfth wrote: Sat Aug 06, 2022 6:34 pm I wonder why Nasa doesn;t use the same technology as Facebook to produce stereo or 3-D pictures. How many people have an old set of red and blue paper spectacles lying around?
Phobos again!

I really like the 3D model at the APOD caption's link: asteroid-like moon's.
(Scroll down to the second image, which is wonderfully interactive).
Thanks a bunch for 3D Phobos! I have lost my red/blue glasses, never liked them much anyway, and can't do cross-eyed viewing.
The leading theory of the origin for Phobos and Deimos is that they are captured asteroids. According to Wikipedia, this theory is not without problems.
https://en.wikipedia.org/wiki/Mars
But both have circular orbits, near the equator, which is unusual for captured objects and the required capture dynamics are complex.
It'll all make a lot more sense when we locate the door in one of the darker craters. :-P
Yeah, who knew that Phobos and Deimos are really humongous alien-built spaceships? :rocketship: :D

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Re: APOD: Stereo Phobos (2022 Aug 06)

Post by SeedsofEarfth » Tue Aug 09, 2022 10:28 pm

One 3-D technology (aside from Facebook) that used to be quite effective in creating a real 3-d effect without was by polarising the light from the subject using two lenses that polarised at different angles so that each eye saw a slightly different image in each eye. Melded together by the brain, the depth perception was remarkable. I remember using those polarising glasses in movie theaters back in the 1950s and 1960s. As for Facebook:
How do I create a 3D photo on Facebook?
Tap "What's on your mind?" at the top of your Feed or tap "Write something"... in a group.
Tap Photo/Video.
Select your photo and tap Done.
Tap Effects.
On the Choose Effect panel, select 3D.
Add any text you'd like, then tap Post.
However, I'm not sure about the actual process that converts a 2-D image into a 3-D image.

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Re: APOD: Stereo Phobos (2022 Aug 06)

Post by johnnydeep » Wed Aug 10, 2022 1:07 pm

SeedsofEarfth wrote: Tue Aug 09, 2022 10:28 pm One 3-D technology (aside from Facebook) that used to be quite effective in creating a real 3-d effect without was by polarising the light from the subject using two lenses that polarised at different angles so that each eye saw a slightly different image in each eye. Melded together by the brain, the depth perception was remarkable. I remember using those polarising glasses in movie theaters back in the 1950s and 1960s. As for Facebook:
How do I create a 3D photo on Facebook?
Tap "What's on your mind?" at the top of your Feed or tap "Write something"... in a group.
Tap Photo/Video.
Select your photo and tap Done.
Tap Effects.
On the Choose Effect panel, select 3D.
Add any text you'd like, then tap Post.
However, I'm not sure about the actual process that converts a 2-D image into a 3-D image.
I see no 3D option when posting a picture with the Facebook website on my PC. Perhaps it's only available on the Facebook app? Oh well, I detest Facebook anyway.
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Re: APOD: Stereo Phobos (2022 Aug 06)

Post by Chris Peterson » Wed Aug 10, 2022 1:31 pm

johnnydeep wrote: Wed Aug 10, 2022 1:07 pm
SeedsofEarfth wrote: Tue Aug 09, 2022 10:28 pm One 3-D technology (aside from Facebook) that used to be quite effective in creating a real 3-d effect without was by polarising the light from the subject using two lenses that polarised at different angles so that each eye saw a slightly different image in each eye. Melded together by the brain, the depth perception was remarkable. I remember using those polarising glasses in movie theaters back in the 1950s and 1960s. As for Facebook:
How do I create a 3D photo on Facebook?
Tap "What's on your mind?" at the top of your Feed or tap "Write something"... in a group.
Tap Photo/Video.
Select your photo and tap Done.
Tap Effects.
On the Choose Effect panel, select 3D.
Add any text you'd like, then tap Post.
However, I'm not sure about the actual process that converts a 2-D image into a 3-D image.
I see no 3D option when posting a picture with the Facebook website on my PC. Perhaps it's only available on the Facebook app? Oh well, I detest Facebook anyway.
We would not want APOD images displayed like this. The image is analyzed, and based on what the AI thinks is going on, a depth map is created, and then different views are simulated, with missing background estimated from the surrounding image. An animation is then created. Sometimes it works pretty well. Sometimes the AI fails miserably and you get truly bizarre artifacts.

Starting with true 3D data (e.g. an image pair) you could create a similar animation. I think I've seen software that would do that. But it's up to an image author to decide if they want to do that, and up to the editors if they think it would make a good APOD. In scientific publications, however, the standard way of presenting stereo data is with a pair of images, viewed either directly or using a pair of lenses (like a stereoscope). Occasionally anaglyphs like this APOD are used, but not commonly, since it requires special glasses and you lose color information.
Chris

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Re: APOD: Stereo Phobos (2022 Aug 06)

Post by johnnydeep » Wed Aug 10, 2022 2:27 pm

Chris Peterson wrote: Wed Aug 10, 2022 1:31 pm
johnnydeep wrote: Wed Aug 10, 2022 1:07 pm
SeedsofEarfth wrote: Tue Aug 09, 2022 10:28 pm One 3-D technology (aside from Facebook) that used to be quite effective in creating a real 3-d effect without was by polarising the light from the subject using two lenses that polarised at different angles so that each eye saw a slightly different image in each eye. Melded together by the brain, the depth perception was remarkable. I remember using those polarising glasses in movie theaters back in the 1950s and 1960s. As for Facebook:
How do I create a 3D photo on Facebook?
Tap "What's on your mind?" at the top of your Feed or tap "Write something"... in a group.
Tap Photo/Video.
Select your photo and tap Done.
Tap Effects.
On the Choose Effect panel, select 3D.
Add any text you'd like, then tap Post.
However, I'm not sure about the actual process that converts a 2-D image into a 3-D image.
I see no 3D option when posting a picture with the Facebook website on my PC. Perhaps it's only available on the Facebook app? Oh well, I detest Facebook anyway.
We would not want APOD images displayed like this. The image is analyzed, and based on what the AI thinks is going on, a depth map is created, and then different views are simulated, with missing background estimated from the surrounding image. An animation is then created. Sometimes it works pretty well. Sometimes the AI fails miserably and you get truly bizarre artifacts.

Starting with true 3D data (e.g. an image pair) you could create a similar animation. I think I've seen software that would do that. But it's up to an image author to decide if they want to do that, and up to the editors if they think it would make a good APOD. In scientific publications, however, the standard way of presenting stereo data is with a pair of images, viewed either directly or using a pair of lenses (like a stereoscope). Occasionally anaglyphs like this APOD are used, but not commonly, since it requires special glasses and you lose color information.
I realize such a simulated 3D effect would likely serve no scientific purpose. I was just curious what the result would look like.
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Re: APOD: Stereo Phobos (2022 Aug 06)

Post by Chris Peterson » Wed Aug 10, 2022 2:31 pm

johnnydeep wrote: Wed Aug 10, 2022 2:27 pm
Chris Peterson wrote: Wed Aug 10, 2022 1:31 pm
johnnydeep wrote: Wed Aug 10, 2022 1:07 pm

I see no 3D option when posting a picture with the Facebook website on my PC. Perhaps it's only available on the Facebook app? Oh well, I detest Facebook anyway.
We would not want APOD images displayed like this. The image is analyzed, and based on what the AI thinks is going on, a depth map is created, and then different views are simulated, with missing background estimated from the surrounding image. An animation is then created. Sometimes it works pretty well. Sometimes the AI fails miserably and you get truly bizarre artifacts.

Starting with true 3D data (e.g. an image pair) you could create a similar animation. I think I've seen software that would do that. But it's up to an image author to decide if they want to do that, and up to the editors if they think it would make a good APOD. In scientific publications, however, the standard way of presenting stereo data is with a pair of images, viewed either directly or using a pair of lenses (like a stereoscope). Occasionally anaglyphs like this APOD are used, but not commonly, since it requires special glasses and you lose color information.
I realize such a simulated 3D effect would likely serve no scientific purpose. I was just curious what the result would look like.
Here's an example. Might have to click on it to get the full animation.
_
e6y0st1vngjjubdrsa8x.gif
You do not have the required permissions to view the files attached to this post.
Chris

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Re: APOD: Stereo Phobos (2022 Aug 06)

Post by johnnydeep » Wed Aug 10, 2022 3:30 pm

Chris Peterson wrote: Wed Aug 10, 2022 2:31 pm
johnnydeep wrote: Wed Aug 10, 2022 2:27 pm
Chris Peterson wrote: Wed Aug 10, 2022 1:31 pm

We would not want APOD images displayed like this. The image is analyzed, and based on what the AI thinks is going on, a depth map is created, and then different views are simulated, with missing background estimated from the surrounding image. An animation is then created. Sometimes it works pretty well. Sometimes the AI fails miserably and you get truly bizarre artifacts.

Starting with true 3D data (e.g. an image pair) you could create a similar animation. I think I've seen software that would do that. But it's up to an image author to decide if they want to do that, and up to the editors if they think it would make a good APOD. In scientific publications, however, the standard way of presenting stereo data is with a pair of images, viewed either directly or using a pair of lenses (like a stereoscope). Occasionally anaglyphs like this APOD are used, but not commonly, since it requires special glasses and you lose color information.
I realize such a simulated 3D effect would likely serve no scientific purpose. I was just curious what the result would look like.
Here's an example. Might have to click on it to get the full animation.
_
e6y0st1vngjjubdrsa8x.gif
Thanks (yeah, I had to click to see it). It's glaringly obvious where the algorithm had to fill in missing pixels by interpreting nearby pixels (like the dog's fur), but of course, all the details must be either lost or guessed at. In this case, it seems to have been lost and filled in with a fog like color instead. Good for the quick "that's cool!" factor, but useless for science.
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Re: APOD: Stereo Phobos (2022 Aug 06)

Post by rstevenson » Wed Aug 10, 2022 11:26 pm

Way back in my youth, my first real job was at the Department of Highways of Ontario (Canada). Briefly I used stereo pairs of aerial photos to look at planned highway routes in 3D. The process was pretty simple and quite effective. But the photos were taken very carefully from a known height, so the viewer lenses could be rigidly fixed to a frame and just slid over the photos. Apparently the process is still used, though digitally, in a variety of geotechnical tasks.

Rob