Pathfinder site, for comparison with HIRISE Options

[AndyG]

Reality to one side - naturally the Romantic in me sees the plucky little rover wandering across the Martian sands, stopping now and again only to admire the view (and because of the darkness at night), wondering why she's not heard from home...

...0.4 m/min for 9-and-a-half-years makes for - a thousand kilometres! Hey, she could be just have made it to Viking 1, or be halfway to Oppy by now.

(Is MSL reading this???)

Andy

[tedstryk]

Nix, I hope you don't mind my blatant rip-off of your site.

[Nix]

No I don't mind at all, it's quite amusing actually!

What's picture #77?
I really enjoy your work on MPF btw... and glad to see your site growing!

Nico

[tedstryk]

No I don't mind at all, it's quite amusing actually!

What's picture #77?
I really enjoy your work on MPF btw... and glad to see your site growing!

Nico

It is a fragment of an image that would have been very similar to sol 78, but most of it was lost in transmission (I am not sure if this happened between Sojourner and the lander or between the lander and earth).

[djellison]

I'm still wondering how you did those - superb work, a data set that needed a proper 'going over' - and oh boy did you do that

Doug

[tedstryk]

I'm still wondering how you did those - superb work, a data set that needed a proper 'going over' - and oh boy did you do that

Doug

To tell it the short way, slowly.

To tell it the long way, the first part was figuring out how to put the puzzle together. The images were all transmitted in little subframe chunks, with the exception of four large images. Those four images all had areas that were horribly overexposed in some of the colors. Then I picked an image to use as my standard (after converting everything to 16 bit). I did my best to tweak the brightness and contrast of the other images until they matched. Also, in a few of the images, I had to correct for shadows moving between the framlets. In some of the very underexposed framelets, I had to do a lot of noise reduction, and I had to adjust the color to correct for the fact that there was an annoying "glow" in blue that skewed dark areas. Once this was done, I re-aligned the color channels. Most significantly, the green channel.

Doug, I think it was you who once asked about making red-blue images and chucking the green channel. This does not work well, because the CCD had far more green pixels than anything else, so the already really bad resolution gets worse. However, there was an annoying echo in the green channel, which had to be reconstructed for each image, and then subtracted. I greatly smoothed the color data, using photoshop's smart blur so as to blur together groups of pixels without bleeding occuring between the surface and pieces of the rover.

I wish I couldh have automated the process of cleaning and aligning the channels. However, nearly all the mosaics of framelets only cover a fraction of the CCD, and there is no information on the PDS cd to indicate where on the CCD each one is from. Since the severity and the direction of the distortion varies throughout the image, one had to manually assess the situation for each image.

One problem was the fact that the camera used some type of auto-stretching. So, if there was a glint off a piece of a rover in an image, the surrounding area would be nearly black. Then, in the next image, with no glint, it would be a nice, bright, well exposed image. With no guide to calibrate the rebalancing process, a lot of guesswork was required. Also, because the bright areas were totally saturated (most of the time), it required a lot of guesswork to reconstruct the greyscale to match other images. Often, pieces of the rover were washed out in some of the channels. That is why color varies in some of the images...a standard was really hard to find.

Soon, I hope to do the much easier task of working with the front camera images.

[djellison]

Thanks for that The real pity is that they didn't get a GOOD colour image of the lander. A few nice B'n'W ones - but not a nice colour one really.

Doug

[tedstryk]

I don't think it ever got ANY color images of the lander.

[djellison]

Hmm - I'm sure I remember an image that showed a bit of egress aid - but now I'm not so sure. Maybe an overactive imagination coloured in a greyscale one.

(edit...

Perhaps I thought it was this one - http://pdsimg.jpl.nasa.gov/data/mpfr-m-rvr...lr/r1557518.htm

but looking at your work - it's just bracket )

Doug

[tedstryk]

I have seen that identified as the lander. However, here was Sojourner's orientation that day (and it didn't move much on the sols immediately before or after that):


And here is the view from the front camera:



As you can see, there is no way that could be the lander.

[elakdawalla]

Hi Ted,

Fantastic work again with these images. In your post immediately above, the comparison of the image of the rover from IMP to the picture seen from the rover was REALLY useful to help me visualize what the heck it was that Sojourner was looking at. If it's not too much trouble, I think it'd really help to put similar images, where available, on your Sojourner images page, to help provide that context.

--Emily

[tedstryk]

Thanks. I am planning to do that, as well as process the images from the other rover cameras. I just got to the point, after doing these, that I didn't even want to think about Sojourner for a while

It is possible that on sol 14, the rover caught a bit of the lander. It moved, and may have at one point been pointed a bit more directly at the lander than this image.





That might be a bit of an airbag in the upper right-hand corner. Might not.

[lyford]

Ted - let me add to the chorus of praise! And i am so glad to see the webpages coming back up....