We do. The big picture dictates the driving trend. There's no point having a 'two week' map only to find we're two weeks down a dead end into a dune field.

This
http://maps.google.co.uk/?ie=UTF8&ll=5...041113&z=15
doesn't tell me how to get to London.


This, however, does
http://maps.google.co.uk/?ie=UTF8&ll=5....262451&z=8

I'll see what I can do - it will be pretty large though.

Maybe you are misinterpreting this quote from Paolo's post:
"You do not need to process the entire image, just the portion south of Victoria."
(There's a difference between 'just the portion South' and 'the portion just South'.)

He's saying don't bother with anything North of Victoria, but process as far south of Victoria as the image goes. He even says he will provide MRO coverage even further south as soon as it is available. He gives categories of areas he wants marked. No mention of marking paths, or one path, is made. It seems he is reserving this duty for the MER team. Imagine!

I don't know if any of you have read Edward de Bono's "The Six Thinking Hats," but what Paolo is asking for is White Hat Thinking: just the facts, without our interpretations thrown in. The problem is coming up that we are all trying to be "useful" (or even worse, "right") by injecting our own egos and assessments into the request. That's not what is needed at this point.

He's not asking for us to solve the problem, just to lay out the data so that we get all the facts on the table. That's the way we can be most useful at present.

I highly recommend de Bono's process for anyone who has complex problems to solve. See his website for more info about his system.

Awesome!!!

Would it be easier to break it up into two or three pieces?
(I suppose they could always be reassembled later into a lower-res global picture)

-Mike

Let me make sure my intent is clear. At the moment I want to map the hazards. Since there are many algorthms that give good answers, I want to see how difficult is to map a path using these tools you have created. There's nothing particularly magic about finding a path but it requires knowledge of a few things that I am not sure I can talk about.
Also for the moment there is no need to analyze the area north of Victoria (terrain we have already driven on).

Paolo

Hi Paolo,

Could you give us some guidance on what you mean by large ripples? Are they what is in the eastern half of Erebus, or do you mean even larger than that? Approximately what percentage of the full Erebus image we have been playing with would you consider large ripples? Thanks!

Bill

Oh yes, I break the jp2 into chunks 5152 pixels high so you'll get it in those size chunks - but 29794 x 5152 is still a HUGE jpg.



I'm at that stage now and am assuming:

Green - no ripples or very (Insignificantly) small.
Blue - Ripples smaller than Purgatory (or maybe even the ripples around Purgatory if not enough comes out red)
Red - Larger than Blue ripples

I'll let you know when its done.

Among the things you can talk about, what is the most unusual, unexpected or bizarre navigation cue you used for mapping a path?


Paolo Amoroso

I consider large ripples those that are higher than purgatory and with distance between ridges that were wide enough for navigation. 3-5m between ridges?
Remember that what is characteristic of purgatory style ripples, is not necessarily the size, but the fact that the ripple is curved.

Paolo

Bill,
I like what you're doing with a 2D FFT.

Since Paolo mentioned he's interested in finding spots where the ripples converge (as happened in purgatory) it strikes me that it would be possible to do some editing in the frequency domain and suppress the main trend of the periodic ripples, and then convert back into the spatial domain. In such a reconstructed image, the main trend of the ripples (generally north - south in this region around Victoria) should be suppressed, while other irregularities (crater rims, ripples intersecting the main trend) would remain. Those would then highlight areas to avoid -- or at least where the Rover Drivers should exercise caution.

Do you (or anyone else) think you could give that idea a try?

All the best, Steve M

The tie-down cleats on the wheels. The rovers were secured on the lander by bolts and the location on the wheel has deep cleats that have the characteristics of capturing soil on on side of the and depositing the soil on the other side and they leave pretty distinct marks on the terrain. We can measure the distance of these markings and determine slip even without running Visual Odometry. When the slip is very large (80% and up) the cleats leave the soil in small mounds. In Purgatory we were able to determine pretty accurately the actual motion of the rover during sol 446 (the sol where the rover got embedded). This gave us some information to verify our physical simulation in the sandbox. That means we wanted to make sure the simulated embedding we generated in the sandbox was as accurate as possible. This allowed to verify the way Opportunity was going to recover from the embedding event. Not only we wanted to make sure Opportunity would be reovered, but also wanted to compare the progress on Mars vs the progress in the testbed

Paolo

If you are on Linux, you can make crops of the image using IAS Viewer and a xorg.conf tweak.

Open /etc/X11/xorg.conf and under the Screen section, subsection Display, add a line "Virtual 2560 5120" (or any other dimensions), save and restart. The desktop will cover a bigger area, which you can navigate moving the mouse to the screen edges. Run IAS Viewer maximized to save the crops. If the algorithm 'bleeds' at image edges you'll need to keep some overlapping margin.

Steve M.,

I think that filtering in the 2dfft domain is a nice idea. I think it will be important to not just cut out some components, but smoothly suppress them with some sort of dampening field. Sharp edges in one domain makes ringing in the other. I've got a couple of other ideas to work on first, but I'll keep it in mind. Thanks!

Bill