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Posted by: Nirgal Feb 23 2010, 07:58 PM

I'm currently exploring the application of my single-image photoclinometric 3D reconstruction algorithm to generate DEMs for various areas of interest, in particular where we have no other (i.e stereo-imaging based) detailed 3D reconstructions yet.
One of the first areas I have always wanted to visit "from the ground" is the famous Dust Avalanche caught live in action by HiRISE.

Follow http://www.thethirdplanet.de/mars_gallery/Dust_Avalanche/index.htm for a small web gallery with color 3D renderings of a DEM derived from the originally published HiRISE image, rendered under various viewing positions and light source directions.

http://www.thethirdplanet.de/mars_gallery/Dust_Avalanche/index.htm

The original 2D image can be found at the HiRISE site under the observation ID http://hirise.lpl.arizona.edu/PSP_007338_2640

Disclaimer: The single-image derived 3D DEMs are mainly intended for visualization purposes. Although they are quite exact at reproducing relative heights at small scales, they are less accurate with respect to absolute heights at large scales.

Posted by: Juramike Feb 23 2010, 08:07 PM

Awesome!!!

Posted by: Stu Feb 23 2010, 08:28 PM

That is just... well I can't use the word I want to use, so I'll just go with "nuts"...!!!!

Seriously, fantastic work. I get the very real feeling that you've opened the door on a whole new way of looking at, and visiting, Mars with these images of yours.

Posted by: nprev Feb 24 2010, 02:09 AM

Although it is well known that I studiously abstain from profanity of any sort, your images did cause me to utter a few choice expletives, Nirgal. Marvelous!!!

Posted by: Astro0 Feb 24 2010, 09:21 AM

Wait Where did my jaw go?!

Oh, there it is ..... ON THE FLOOR!!!!!!

Incredible work Nirgal.

On Mars, On Mars, On Mars!

Posted by: Bjorn Jonsson Feb 24 2010, 11:14 AM

This is awesome. Are you taking into account the fact that apparantly there are large albedo variations in the source image? The terrain at left in the source image looks brighter than the terrain in other parts of the image.

Posted by: ustrax Feb 24 2010, 04:48 PM

Man...just want to punch you!

Posted by: Explorer1 Feb 24 2010, 09:56 PM

Incredible... like we're soaring right by it!

Makes me wonder if the avalanche made a detectable noise if anyone had been close enough to hear it when it happened.

Posted by: Nirgal Feb 24 2010, 10:13 PM

Very good question, Björn: I for myself was quite surprised on how well the large albedo differences got handled by the reconstruction algorithm that in theory should have more trouble with stark albedo variations.
I did notice remarkable "albedo-robustness" before, in particular when I tried reconstructions of sand dune surfaces that contain large dust devil streak patterns whose extreme albedo differences should in theory disturb the reconstruction process, which, fortunately does not seem to be always the case and the streaked dunes DEMs got reproduced quite well:

I suspect that it is the various adaptive regularization terms I put into the optimization process that alleviate the albedo problem to some extend.
Of course the perfect solution would be some sort of true albedo-correction based on stereo or altimeter-based DEMs but then again such data is not available for many regions ...

Posted by: vmcgregor Feb 25 2010, 06:00 AM

Wow! Speechless. So beautiful!

Posted by: vossinakis Feb 25 2010, 04:20 PM

awesome and quite unique!!!

Posted by: tedstryk Feb 25 2010, 07:11 PM

Wow, exceptional! I love having the opportunity to see something like this from the ground that I would never actually want to see from the ground (because landslides hurt).

Posted by: Tesheiner Mar 2 2010, 08:59 PM

> with this HiRISE data I was able to do some full detail 3D renderings posted at the other thread where it is more on topic

That's correct. Moving posts...done!

Posted by: CosmicRocker May 26 2010, 04:02 AM

As is often the case, I am a little late getting to this party. I am at a loss for words, but "Holy Moses!" comes to mind.

Posted by: David S. Jun 26 2010, 09:54 AM

Just wanted to point out that congratulations are in order for Nirgal who's the subject of the first article of next month french astronomy magazine "Ciel et Espace", following a little article published a couple months ago in which this very forum was also referenced.

http://www.cieletespace.fr/image-du-jour/4926_une-avalanche-martienne-en-3d