http://www.unmannedspaceflight.com/doug_im...s_orbit_res.wmv ( 8 Meg )

Simulated resolution of the various cameras on orbit at Mars right now - all the way from 100000 to 30 cm

At least - once the FTP is back up and running. Grrrr..

I just hope Google Maps don't try and send me to jail for using their pictures

Doug

Doug:

Very informative - thanks! It puts it all in perspective...

Bob Shaw

Doug - you may have just found a good use for the Millenium Dome, might even be the first.

I actual visited it. Bloody terrible it was.

I picked it because I needed a big object of known size to measure to cross check the scale on google maps, that, and I knew the kids in the lecture I gave last week would enjoy whistling the East Enders themetune as I zoomed in

Doug

Very useful, but a couple of observations: first, maximum THEMIS VIS resolution is 18m, not 12m (probably close enough). More importantly, I would say that this overestimates the true image quality at all resolutions. The highest resolution images in Google Maps are from scanned air photos, which probably have roughly 3x the sharpness of satellite images at equivalent sampling.

I usually advise that people run a blur filter of about 1.5-2 pixel radius for these sorts of simulations. Of course, it depends on the point you're trying to make.

I knew you'd appear in here I was thinking to my self "what will MC say.." when I made it..

Thus the phrase "Quoted resolutions simulated...." at the end there, and not 'Simulated resolving power' or something like that. It's simply answering the questions "what does X m/pixel look like". I remember my old MOC / HiRISE MER simulation - and that was exactly .25cm per pixel and 1.5x0.5 m/pixel - not softened in any way - basically saying "if they actually got the figure mentioned, then it would look like this" - and to be fair, the most recent MOC CPROTO image of Spirit on Husband Hill is pretty close to my simulation.

I was sure I was on the money with the figures (somehow I got 12 in my head with Odyssey - that figure is around somewhere, but 18 is around a lot more - and is too close to HRSC's 12 to bother demonstrating, I may just drop the Themis VIS reference...no offense ) , I'm hoping to do a second version that includes TES and CRISM footprints, and something about Omega as well.

Good points well made though - and a disclaimer on the end shot is probably appropriate next time around.

Doug

Doug:

Why not drop a simulated MER into each image, too, so that the viewer can judge the visibility of the puir wee things?

Bob Shaw

Or do the powers of ten thing i.e., a mega zoom sequence from earth based images of mars, though orbital, to reprojected polar, down to MI images .

A Hubble, Viking, MGS, MER reprojected map, polar to PANCAM, MI finishing on a blueberry. It would be nice if the images are aligned, done right it would look a little like the Ranger lunar crash sequences

HiRise Site Sample Image has a zoom to 11 cm / pixel resolution.

Incorrect? Or a very loose comparison?

11cm is too high - the best quoted res is 25 or 30 depending on where you look, and as MC will tell you, the likely resolution is probably more likely to be double that.

Doug

Isnt that the same as many of the MGS images? With that special technique they've got down to 50cm. MRO isn't going to be much of an improvement over MGS?

MRO will have higher signal-to-noise and higher NATIVE resolution than the best motion compensated and along-track oversampled MOC images, and the central strip (damn wide strip) will be in color.

The higher signal-to-noise is important. MOC data at full resolution frequently shows nothing but random noise down at the single-pixel scale over large areas of the flatter and blander surface between discrete topographic features. That's one reason a lot of MOC data is taken averaging pixels. a 2x2 pixel average cuts resolutin in half, but .... square-root-of-4... cuts random noise by half, too.

The very best resolution at which imagery is taken with MOC is about 1.5m across track and 0.5m down track.
MRO can take imagery at 0.3m across and down track.

Now - the actual resolving power is up for debate

Doug

So maybe this simulated view of Mars Polar Lander is a bit optimistic lol?

http://mars.jpl.nasa.gov/mro/gallery/artwork/MRO_hirise.html

Yes - exactly.

Doug

I was wondering if JPL can use the imaging technique done with MGS to increase its resolution when it was looking for MPL on MRO?

It doesn't need to -- HiRISE is always doing "time-delay integration", which has the same effect but is done internally in the instrument. For this to work, though, it requires that the spacecraft attitude is very stable, and there are some concerns about that.

SS mentioned that when I met him last autumn - I guess these test images will help answer at least part of that question, if not to the level of accuracy of the final orbit. I've read some HiRISE docs (via the power of google) that mention quite a lot of detail about pulling good images out of the data even if the jitter gets in the way a little, but of course, jitter on a time frame of the life of one pixel dropping down the 128 pixels of TDI is going to cause a lot of trouble.

Doug