Live Dust Devil? Options

[tedstryk]

Another one East of Clarke Hill
http://qt.exploratorium.edu/mars/spirit/fo...I4P1214L0M1.JPG
I wonder if we will see one in Tennessee Valley someday

That is a great shot! Too bad it is from a hazcam.

[Trader]

And we thought we may never be lucky enough to catch a live Devil -- now we see them everywhere much of the time (in season). Makes one wonder how old the large streaks seen in satellite pictures are or are not. Looks like a very dynamic surface at least from a weathering point of view. The truly large Devil events may be really rare but the small ones certainly aren't and a lot of dust gets moved around -- even onto and off of our little year old rovers. Are the erosion effects and dune structures we observe much younger than originally thought? Do we see variations in the satellite shots over the few years we've been able to view them in good resolution?

Trader

[Tman]

Another one East of Clarke Hill
http://qt.exploratorium.edu/mars/spirit/fo...I4P1214L0M1.JPG
I wonder if we will see one in Tennessee Valley someday

That is a great shot! Too bad it is from a hazcam.

Really it's a pity, that was an especially beauty one. Maybe there are still navcam pics to download.

[tty]

And we thought we may never be lucky enough to catch a live Devil -- now we see them everywhere much of the time (in season).  Makes one wonder how old the large streaks seen in satellite pictures are or are not.  Looks like a very dynamic surface at least from a weathering point of view.  The truly large Devil events may be really rare but the small ones certainly aren't and a lot of dust gets moved around -- even onto and off of our little year old rovers.  Are the erosion effects and dune structures we observe much younger than originally thought?  Do we see variations in the satellite shots over the few years we've been able to view them in good resolution?

Trader

Large-scale albedo changes between one opposition and the next have of course been well documented since back in the nineteenth century.

tty

[wyogold]

Ok can sombody give me a step by step to cancle out the background in photoshop? do i just do a positive and negative image and merge them?? thanks

scott

[alan]

more dust devil movies
http://marsrovers.jpl.nasa.gov/gallery/pre.../20050506a.html

[wyogold]

more dust devil movies
http://marsrovers.jpl.nasa.gov/gallery/pre.../20050506a.html

SWEET

scott

[Tman]

Wow, one dust (tornado) devil was about 200 meters high (Hills approx. 80 meters over ground). I most like this dust devil armada wandering through Gusev.

[Tman]

Ok can sombody give me a step by step to cancle out the background in photoshop? do i just do a positive and negative image and merge them?? thanks

scott

You can use the "background-eraser" for that. Erase with it in the background layer. But you must know, then you only can save your picture as GIF-file, if you want it without background.

[dilo]

Many other devils in last 3 sol, last one is pretty impressive:

The two frames are 201sec apart...I hope someone want to make enhanced version!

[Guest_Edward Schmitz_*]

Frist View

Second View

It's kind of crude, but I like it.

ed

[dilo]

Frist View

Second View

It's kind of crude, but I like it. 

ed

Good work Ed... I can see dust also in the sky portion of 2nd image!
Which technique do you use?

[wyogold]

I showed how to do this in the image section of this forum but i'll post a quote here

OK I posted questions in the live dust devil topic and didn't get much response.
I have now done some tries at enhancements but I am not a Photoshop wizard.
I am getting close to the enhancements that JPL does but something is missing.
My images turn out grainy when I tweak the contrast. Here is the process.

1. select 2 images that are the same view, size and filter. (preferably one with dd and one without.)

2. invert (negative) one of the images.

3. select all on the inverted image

4. paste to the other non inverted image

5. decrease the opacity of the inverted image layer to 50%

6. merge visible

7. increase contrast (this is where things are going not quite right)

you now have an image that is only what has changed between images. (like dust devils or such)

Now you can take the image and place it back over the original to enhance the dust devil.

I would really appreciate it if somebody more adept at modifying images could tell me what I'm doing wrong and why my images don't look like jpl's. thanks

Wish I had more time to do this with all the frames and build a movie.
My earth rocks are getting in the way of my mars rocks *sigh*

Here are my attempts. One raw and another running it through a filter or two before combinding with the original.







scott

enjoy
scott

[dvandorn]

We've all seen the dust devil movies posted May 6 at the JPL MER site... but I haven't noticed anyone mentioning the last set on the page. Not only does that last movie capture the by-now "standard run" of small dust devils dancing across the plains, it captures two of the very large variety, whose bases were likely hidden by the curvature of the horizon but which you could see towering into the air hundreds and hundreds of meters.

These are the *big* dust devils that have been observed from orbit. I was beginning to wonder if they co-existed within Gusev with the smaller variety. I guess I never made it to the bottom of that page before today... shame on me.

Here's the link -- notice that while there is one very obvious large devil on the horizon, there is another one about one-eighth or of the image width to the left of the strongly visible devil that blows in and out of view:

JPL MER Site

The large devils on the horizon look quite a bit different from the little ones we can see dancing along the plains in the foreground -- they're taller, they entrain more dust, they remain coherent for longer periods, and they move more slowly (at least relative to the frame). During the time the major large devil takes to move a tiny amount, four or five little devils dance across the frame out on the plains. In fact, it looks like one little devil passes very, very close to Spirit, near the end of the sequence.

-the other Doug

[slinted]

Spirit caught another great dust devil, in the sol 483 navcams. It is in at least 7 of the frames, and seems to be posing for the camera...starting out at left side of the frame and traveling across to the right over the course of about 10 minutes.

Here's an enhanced movie (using the difference image technique, with a scaling factor of 4 on the difference image before being added back to the median image):
http://www.lyle.org/~markoff/collections/s..._sol483_nav.gif

source images : http://nasa.exploratorium.edu/mars/spirit/navcam/2005-05-18/