Like a lot of people, the new HiRise imagery has had me scrambling to learn about JPEG2000 (jp2) files, and trying to find software and plugins for manipulating and editing them. A lot of that discussion has been taking place in the MRO 2005 topic. We now have two MRO passes providing amazing stereo over much of Opportunity's trek, and it sounds as if we will soon have some Spirit coverage. I can hardly wait for that.

Anyway, I'm starting this thread for anyone wanting to post new HiRise imagery of places Opportunity has explored in the past. I'll start it with an anaglyph.

Even though Meridiani is pretty flat, the MRO images were so fine that I really wanted to see how much detail I could get from them. Spectacular Victoria has already been nicely done, so I had to look elsewhere. I thought Beagle Crater and the transition to Victoria's annulus would be of interest to some people. I'll post this as a jpg that fits the forum size limit, but should we sometimes use the better jp2 format even though all users may not be prepared to view them?
Click to view attachment

This is the Payson/Mogollon area of Erebus.

Phil

Click to view attachment

I would not use JP2 fo regular forum posts. It would be a serious problem for most users.

Purgatory is the light spot at the center of this image. Tracks coming in are more visible than those going away.

I am struck by the number of 5- to 10-meter circular depression features I can see scattered through the dunes, both in the Payson view and (especially) in the Purgatory view linked above.

I'm not as familiar with the full panoply of drift structures as some others here -- are such circular features common in windblown drift/dune structures on Earth? 'Cause these look like cratering remnants to me...

-the other Doug

It's very nice looking. Nevertheless, as on Doug's anaglypk of Victoria, it seams MUCH deaper than it is. Anybody can explain this ?

Ah ah ah ElkGroveDan, after been a Beacon specialist you've turned to be a Purgatory specialist now. Not easy to spot, good work (I know, it was Tuvas that...).
OK, we lost this Beacon pool, but what, do we realy need purgatory ?

Your eyes are perhaps 10cm apart. The two HiRISE observations were probably taken from 100km apart (I'm guessing that figure, but you get the idea) Hence, even if you do the maths for say, the Human eye looking at this terrain from 100ft high, the two HiRISE obs are like UBER stereo vision

Doug

Here is an anaglyph of Erebus. There is not a large amount of vertical relief here. It's essentially a shallow dish, but things like the monster drifts, the outcrop cliffs, and Payson promontory stand out.
Click to view attachment

The vertical exaggeration that is apparent in stereo imagery is a function of four variables, including the distance between the orbiter when each image is acquired, the height of the orbiter, the distance between your eyes, and the distance between your eyes and the stereo pair. There is a nice description and diagram on in this remote sensing article.

You'll notice that you have control of one of those variables...the distance between your eyes and your monitor. If you position your eyes very close to the screen, you can reduce the vertical exaggeration. You can increase it by moving away. I find this a helpful way to see small vertical changes. For instance, you can view this Erebus anaglyph from halfway across the room and the monster drifts look like huge dunes from the Sahara. Unless you have the eyes of an eagle, you'll need to zoom the image up to 200-400% original size.

Details confirming this location are here

As for the "Battle of the Beacon" there is no shame in losing a great confilct. I try to live by the words of American President Theodore Roosevelt (served 1901-1909).

Far better is it to dare mighty things, to win glorious triumphs, even though checkered by failure...than to rank with those poor spirits who neither enjoy much nor suffer much, because they live in a gray twilight that knows not victory nor defeat.

Bring on the next great debate!

Oh Yes, I agree! Hope you notice the "we" in my sentence..."OK, we lost this Beacon pool, but what, do we realy need purgatory?". I was definitively on your side and I see that you're not trying something easy by looking after Purgatory. Don't tell me you didn't get the joke

Back on next great debate : anybody found "Bounce rock" ?

The reason for the depth appearing to be much steeper is that the angle between the points is on the order or 20 degrees (That's from memory, not from looking it up, so...). This increased angle gives the appearence of being steeper than it really is. However, this does allow for a higher-precision elevation map to be made, which is exactly what they want for imaging something like Victoria crater.

VEERRRYYYY rough maths. Altitiude of 278k for one ob, 269 for the other - call it 274 average.

20 degrees, 274km..... the 'eye distance' is about 96km between observations.

Doug

...especially this 'peppered' section in Erebus:

The backshell is really getting my attention. The immediate thought from MOC was that the backshell was on the left with the parachute to the right. What appeared to be the parachute it now seems was just the surface disturbance from a very high speed impact of the backshell.....let the gif load for a while, it shows both.

I've noticed the backshell-impact did leave a bigger scar into the surface than the heatshield..

Nico

Is anyone else really surprised at just how much more detail MRO has? There was some debate prior to MRO arriving as to whether it would be drastically different to MGS, but every time I see a direct comparison of scenes taken by both cameras i'm stunned. .

I posted this a while ago:

New HiRISE release includes a third view of Opportunity! Talk about being able to locate the rover's trek precisely...

http://hiroc.lpl.arizona.edu//images/PSP/opportunity.html
http://hiroc.lpl.arizona.edu//images/PSP/O...-step-movie.jpg

--Emily

Yes, me too. They tell me it's not just resolution, but a signal-to-noise improvement. Amazing regardless.

Bouncey bouncey....

Ties in well with
http://photojournal.jpl.nasa.gov/jpeg/PIA05225.jpg


Doug

Neato! Well spotted, Doug!

--Emily

Excellent! How did some of us miss the bounces? What else is hiding in it?

The HiRise people have been busy lately, haven't they? The most recently released images are rightly stealing the show, but the caption from the Victoria anaglyph released today contained some useful information for the vertical exaggeration in stereo discussion. I think they provided the viewing angles for the first two passes over Victoria, which allow us to more accurately calculate the baseline from MRO's viewpoint, using Doug's estimation of the average vertical height of the passes.

The angular separation between the views appears to be closer to 12 degrees, according to
http://hiroc.lpl.arizona.edu//images/PSP/victoria.html

Using simple geometry with the new angles, I calculate about 61 km for the baseline. Using 20 degrees, I essentially get the same number Doug did. Using the formula from the site I linked to earlier and this new data, I calculate a vertical exaggeration for the Victoria stereo as about 1.44 for someone with eyes spaced 7 cm apart and viewing the anaglyph from 18 inches (roughly 45 cm) from their monitor. If that person moved his/her eyes to about 12 inches from the screen, the vertical exaggeration should be around 1:1. Viewing it from 24 inches from the screen should result in a 2:1 vertical exaggeration, etc...

I've created an Excel spreadsheet that can be used to play "what if" games with the variables. I tried to make it somewhat friendly for people who might not be familiar with Excel spreadsheets, so others could experiment with the variables. It can be easily modified for use with other stereo pairs, if you are familiar with spreadsheets. I have tested it enough to convince myself that it seems to agree qualitatively with what I see when viewing this pair of images. If anyone detects errors in it, please make me aware of them. I have been known to screw up.
Click to view attachment

It can be seen that the backshell hit at the rightmost point in the picture, and then skidded/bounced to its final resting place a bit to the left of initial impact. The general bright splotch in the MOC image that encompasses both parachute and backshell fits well with a spray of sand ejected in the first impact of the backshell. Notice how the light-coloured area begins at impact point and then radiates leftward from that point. Now, years later, the colour of the general area is back to the uniform surface colour due to the wind. As with the airbag bounce marks, a light colour indicates a disturbance in the top layer, exposing lower material. At least, that's how I see it. Other opinions?

I think you have it about right - the challenge is now to try and figure out the config. of the backshell on the surface - see how broken it actually is....and that isn't easy

Maybe they could abandon Victoria and just nip back to check it out.....





Doug

Too bad they didn't have these pictures when Opportunity was fighting its way through the dunes.

Look at the third bounce in that image. It catches the edge of a very small crater which then deflects the direction of motion off to the left a bit..just enough to put her down in Eagle. In makes me think that if that first bounce had been just a half meter farther south, it would have missed that little crater and bounced on up to the northeast of Eagle Crater, missing it entirely.

It's like a "giant golf" after all
JPL had realize a very good swing.

Yup - not quite visible in this but you are right...

http://photojournal.jpl.nasa.gov/jpeg/PIA05227.jpg

I've looked for bounces at Gusev....no luck ( maybe the first, but none after that )

Doug

...while Bounce rock doesn't seam to have diverted the trajectory.
Did you notice the 2 whitish spots close to Eagle?
I've tried to find Bounce Rock assuming it was 28 m from the center of Eagle. Frankly I have other candidates but this is an attempt to locate it. May be easier in the raw image. In the absolute, as we've seen Adirondack, BR may be visible too.
Click to view attachment


As I said in Spirit topic, the albedo difference in Sleeping Hollow was quite big seen from Spirit position just after landing. Strange we see nothing there.
What would be interesting too, would be to try to match the DD path of known DD with MRO picture.

It's an impressive attempt at identifying the bounces Doug, but I have to say looking at the original full-scale image, even with considerable stretching, that only perhaps a few of your identified bounces are convincing. There are many other similar vague lightish smudges in the vicinity. It may just be that almost three years of dust deposition has rendered the bounce marks indistinguishable from the background.

Yes - but not on the actual trajectory as dictated by IMU data and matching the bounces as seen in the reconstruction of that data

Doug

I'd assumed that too, then from looking at the airbag bounces, it would be expected that they too would become dimmed substantially, yet they appear pretty fresh as in the picture in post #28, unless they too are substantially dimmed. Although its hard to see any rover tracks in the latest MRO image, i cant even see where Oppy left the crater, i remember being even able to see the rocket firing traces on the sand in the old MOC image, they seem gon enow, perhaps you're right, they really are blown into obscurity now..

Not THAT much - you can still see the three airbag lobes at the point where it dropped into eagle

Doug

Great catch. I think you are right. In the CEPSAR lecture, right after he says "bounce, bounce, bounce, bounce, bounce," SS says, "reading the green perfectly, the trajectory bends to the left, and goes right into this little 20 meter impact crater." What luck.

I find myself replaying that presentation as I frantically load MRO and MOC imagery, and MMB panoramas. This is an amazing time in the Exploration of Mars.

It's like dressing up glasses!
I'd like to see more gifs like this! Or, at least, image couples which show both MOC and HIRISE images. Is it possible? Where coudl I find MOC and HIRISE images for knwon landing sites? I'll do animated gifs or image couples by myself, if somebody can address me to the proper resources!

funny image.
it looks like... well, lander was not the only "bouncing & rolling" thing outh there!!!

Anyway, apart from this, any clue about scale of this image? How much are the bounce prints away one from the other?

could you kindly post an excel95-compatible file?

Doug:

You want to go upstairs?


Bob Shaw

Pardon me -- I came here to arrange a holiday!



-the other Doug

That's easy to do. Click to view attachment edit: Well, I guess it will not be that easy. Apparently the conversion to Excel95 screwed up some of the formatting. But you can correct that by changing the size of some of the cells and the dimensions of the image.

who cares? I need formulas, not formatting!
Thanks for uploading the new version.

I created this page attempting to explain what vertical exaggeration depends on, but I have some problems:
- can't know if page actually works on your PC Sometimes on mine itself I get "invalid bytecode" or a not-working applet; anyway it's a 1.5 MB applet, please wait till download completes
- can't understand how V.E. formula can be obtained by my images/applets.
- looks like V.E. can be calculated from a single point of view (first applet), and it's quite confusing!

Put simply, if the stereo pair are taken from farther apart than human eyes, the 3-d effect is exaggerated. This is an issue with the Viking landers, and some of the foreground pairs are unviewable without processing. Fortunately, as far as calculating distnaces, one simply needs to know the distance between the two "eyes" and the angle of the line between them relative to the object in question.

I understood the "easy version". I was trying to understand the "hard version" , i.e. the geometric deomonstration.