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Endeavour Drive - Drivability analysis
Astro0
post Sep 25 2008, 01:01 PM
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I thought it may be interesting to take part of Fran's map and overlay it with part of Opportunity's route map (in this instance) produced by Phil Stooke. This is just rough, but it gives you an idea of the terrain vs driving route.
Attached Image


Nice work everyone. I'm sure Paolo and others are amazed by what you are able to achieve in such a short time using a variety of tools.
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AndyG
post Sep 25 2008, 01:17 PM
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That's impressive.

Andy
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Tesheiner
post Sep 25 2008, 01:58 PM
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I'm impressed too!

Regarding "Purgatory in red color or not" I wouldn't be surprised to find such area in yellow/orange and the area around "Jammerbugt" in darker color.
We should not forget that Purgatory was a bad event, worst than Jammerbugt, not because of the ripples' size but mainly (imo) because the rover was in "blind drive mode" during those old times and when she got trapped on the ripple she continued turning and turning the wheels for the equivalent of 50m (afaik) without "slip detection" and digging deeper in the sand. That was not the case in Jammerbugt when "slip detection" was in use so it was easier to get out of it.
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Juramike
post Sep 25 2008, 03:10 PM
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I think I've got an improvement, but my ignorance of Photoshop image manipulation is holding me back.

The key will be to blur out the dune waves slightly (what blur tool?, pixel size?), then phase shift by 1/2 wavelength (in pixels), then create the differential (differential? multiply? darken? overlay? then blur???)
Attached Image


Anything that doesn't cancel indicates something shifted (I think I need a blur after the differential is created). So signal after differential = bad/caution; signal cancel = good/drivable
Attached Image


Big dunes will have the biggest signal, since the crests will now no longer cancel.
Smaller dunes (with small wavelength) will cancel somewhat have less signal in the differential image.
Flat drivable pavement will totally cancel out, and have no signal and be dark in the differential image.

(And here's the best part)
Flat pavement with big dunes will still have a big signal, since the phase-shifted dunes will not cancel out the pavement response.

I'll try to fiddle with this tonight (since I don't know the right tools or parameters to do this), but does anyone have any suggestions?

-Mike





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Ant103
post Sep 25 2008, 03:51 PM
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A view toward the flatlands of Meridiani smile.gif


I am wondering that when have been created the right tracks. huh.gif


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jamescanvin
post Sep 25 2008, 03:59 PM
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QUOTE (Juramike @ Sep 25 2008, 04:10 PM) *
I think I've got an improvement, but my ignorance of Photoshop image manipulation is holding me back.


If you keep going down this route you might end up with the Fourier technique that I'm using. wink.gif

Mine effectively boils down to the strength of repeating pattens across parts of the image. Yours is starting to sound like that too.


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RoverDriver
post Sep 25 2008, 04:20 PM
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QUOTE (jamescanvin @ Sep 25 2008, 07:59 AM) *
If you keep going down this route you might end up with the Fourier technique that I'm using. wink.gif

Mine effectively boils down to the strength of repeating pattens across parts of the image. Yours is starting to sound like that too.



Actually his approach is mor similar to correlation which is not rotationally invariant (as applied in this manner). Since the ripples are elongated features and do not change much direction, it seems to be a good approach and the results are quite good.

An important refinement that FT might be able to generate is the detection of purgatory-like drifts. Purgatory not only had a particular height, but the ridge was somewhat diagonal relative to the prevalent ripple direction. I believe I can see some examples of these in the HiRISE south of VC. Visual detection of these drifts might something that the less image processing savy contributors could do.

This image shows what I'm talking about.


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Stu
post Sep 25 2008, 05:23 PM
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Amazing, brilliant work going here, well done everyone who's contributing. I have to be honest: reading all the posts here about the various imaging techniques being tried by people I feel a bit like a dog listening to a lecture on the workings of the LHC, but I applaud you all! smile.gif


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Juramike
post Sep 25 2008, 05:47 PM
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QUOTE (jamescanvin @ Sep 25 2008, 11:59 AM) *
If you keep going down this route you might end up with the Fourier technique that I'm using. wink.gif

Mine effectively boils down to the strength of repeating pattens across parts of the image. Yours is starting to sound like that too.


I think the Fourier technique is going to be the best way to do it. The image-based technique depends on regular waveforms that are all parallel and oriented in the same direction, so that an orthogonal shift cancels stuff out.

Any funky non-parallel patterns will throw the image-based technique off.

('Course the image-based technique doesn't require extra programming or math. laugh.gif )

-Mike


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Juramike
post Sep 25 2008, 05:51 PM
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QUOTE (RoverDriver @ Sep 25 2008, 12:20 PM) *
I believe I can see some examples of these in the HiRISE south of VC. Visual detection of these drifts might something that the less image processing savy contributors could do.


Actually, there might be an easy way to indicate these with the differential shift method as well.

If you shift the second image orthogonally by exactly one big-dune wavelength and take the differential, in theory, all the parallel dune crests should cancel out. Anything that doesn't cancel out (and is therefore bright) is one of these bad dunes.

-Mike


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john_s
post Sep 25 2008, 06:46 PM
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QUOTE (Juramike @ Sep 25 2008, 06:47 PM) *
I think the Fourier technique is going to be the best way to do it.


I agree in theory, but Fran's non-Fourier map of the Erebus region looks pretty close to perfect, at least for that test region. We may already have a winner...

John.
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imipak
post Sep 25 2008, 07:14 PM
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QUOTE (alan @ Sep 25 2008, 04:52 AM) *
Could someone do the same (break up the huge JP2 file into manageable pieces) for the recent HIRES image of the terrain south of Victoria.

I'm trying to do exactly that, though from from the amazing results posted above I think the "Mk. 1 Eyeball" idea has been left in the dust! How big would be manageable - 250px square? 500?

Incidentally for JP2 manipulation I've been using the (non Free) Kakadu tools to convert to ppm.


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jamescanvin
post Sep 25 2008, 07:21 PM
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OK folks, version 1 of my Fourier technique is done for the whole of PSP_009141_1780. I'm still to make lots of high resolution overlays to see just how well it's doing but from first glance it looks pretty good. Here is the coloured version of the HiRISE 'browse' image.



Click for my website with 2048x5380 and 1024x2690 sized versions.

James

EDIT: BTW, This covers all the route so far and then to beyond "mini Endurance"


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SFJCody
post Sep 25 2008, 07:44 PM
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QUOTE (jamescanvin @ Sep 25 2008, 08:21 PM) *
OK folks, version 1 of my Fourier technique is done for the whole of PSP_009141_1780.


Now that is truly excellent! smile.gif I'm pleased to see that Oppy has already passed through a much denser patch of 'red terrain' travelling down past Erebus to Victoria than anything that lies further south!
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efron_01
post Sep 25 2008, 07:49 PM
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QUOTE (SFJCody @ Sep 25 2008, 09:44 PM) *
Now that is truly excellent! smile.gif I'm pleased to see that Oppy has already passed through a much denser patch of 'red terrain' travelling down past Erebus to Victoria than anything that lies further south!


Exactly my idea
if i had seen a map like this before we went to Victoria.. i would have doubted if it could ever reach that crater..
now things look better..
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