Cameras For Msl, MSSS gets all the contracts Options

[slinted]

I'm particularily interested in the MastCam using the Kodak KAI-2001CM interline CCD, which has a good writeup by Kodak at : http://www.kodak.com/global/plugins/acroba...001LongSpec.pdf

Some things I picked up from reading this...

This document lists a minimum storage temperature of -55 C, which would mean that some sort of heating would be required to prevent the temps from dropping that low during the night.

The 3 color bayer pattern on the CM model does allow some IR imaging, same as MER, but its efficiency is much lower from 800nm on, only 10% as compared to 30% at 800nm on MER.

There's a ton more info in there, for those who are intersted.

[tedstryk]

It seems quite difficult to imagine a rover picking such things out automatically. It took much processing of the Pathfinder images before dust devils were identified.

[DEChengst]

It seems quite difficult to imagine a rover picking such things out automatically. It took much processing of the Pathfinder images before dust devils were identified.

That all ofcourse depends on the distance to the dust devil. If it's far away and at the resolution limit of the camera it will be hard to spot a dust devil. If it's close it shouldn't be to hard to see that there is a dust devil. It may be more difficult to have a computer recognise it, but if you don't even try to develop such technology you can be sure you'll never catch a dust devil in a movie.

[DEChengst]

Shortly after the announcment was made that MSSS would supply three camera's for MSL I wrote an email to Michael Ravine with some questions regarding the technical specs of the cameras. It took a while and finally recieved a reply yesterday. All the details are in the three PDF files that appeared on the MSSS website in the meantime, but here is his reply anyway:

MastCam still frames will by 1200 x 1200 pixels.  The exact zoom range
is still the subject of some trade studies, but it be narrower field
than PanCam at the long focal length end of the range (probably by ~3X)
and wider field than PanCam at the short focal length (again, by ~3X).

MAHLI will be able to focus from infinity down to 30 mm, which will
give a resolution of 12.5 microns per pixel.

[jamescanvin]

-- "Mars Descent Imager," Michael Malin, Malin Space Science Systems. The Mars Descent Imager would poduce high-resolution color-video imagery of the descent and landing phase, providing geological context information, as well as allowing for precise landing-site determination.

I'm guessing this is going to be on the rover itself as it's using the skycrane EDL method? If so, could this flashy colour video be used on the surface post landing? I guess the big question is can it even focus on objects that close? If so, it could provide some nice close up pictures of the terrain it's crossing.

Another thought: If they mounted one of these on the skycrane we would get the coolest video ever made as the rover is lowered to the surface!

JC

[centsworth_II]

"could this flashy colour video be used on the surface post landing?"

There will be video on the rover. I don't know if its the same as the decent video. My guess is no.

[djellison]

The descent camera will make a movie - and the mastcam can make movies as well

Doug

[MiniTES]

"could this flashy colour video be used on the surface post landing?"

There will be video on the rover. I don't know if its the same as the decent video. My guess is no.

But is the descent imager on the rover or the Skycrane? I'd imagine it's on the rover as it would have an unobstructed view donward.

[lyford]

Does anyone know the proposed height for the mast of the mast cam? After seeing Meridiani creep along from 2 meters high, it would be nice to have a periscope see out from a higher vantage point....
Some earlier designs seemed to have quite an extendable boom for the cameras, but I can't find any current info. Plenty specs for the camera, but not for the mount....

This one seems to feature an extendable mast:



This one doesn't:

[lyford]

Well, I found this here.

Looks like the mast is no longer El Super Mast, but only a MER style unit. - And we are limited to 2m again.... Oh well, it was fun while it lasted!

[erwan]

Seems Batman will be on board?!

[lyford]

Seems Batman will be on board?!

Yes.
The RTG Heat Exchanger looks even cooler (no pun intended) in isometric view:

[cIclops]

Looks like the mast is no longer El Super Mast, but only a MER style unit. - And we are limited to 2m again.... Oh well, it was fun while it lasted!

This drawing was around back in August last year and note that the filename indicates a date of 8 June 2004 ... a lot has happened since then and a lot will happen, it's too early to say what the final design will be.

[Mark Rejhon]

It seems quite difficult to imagine a rover picking such things out automatically.  It took much processing of the Pathfinder images before dust devils were identified.

Actually, it's easier than you think.

It's Mathematics 101.
(1) Verify rover is stationary (otherwise, don't bother executing motion detect)
(2) Verify camera is stationary (otherwise, don't bother executing motion detect)
(3) Snap picture X
(4) Snap picture X+1 about 0.25 seconds later. (Or you could even do 1 second intervals)
(5) Do simple mathematics of subtracting the corresponding pixels of image X+1 from X
(Optimization: Do this only for every Nth pixel horizontally and vertically, say every 4 or 8 pixels.)
(6) Total up all the differences between the corresponding pixel values between image X+1 from X, from the above step.
(7) If this numeric total SPIKES (either positive or negative bias).... there's motion! Start recording immediately.
(8) If numeric total is pretty close to 0, keep repeating steps 1-7.

With the suggested optimization included, this is easily doable on a slow 10 megahertz radiation-hardened processor, even for 2 megapixel images, processed every 0.25ms, using simplified assembly language. And this still leaves plenty of CPU overhead.

If the motion-detect performance optimization is included, it may miss dust devils smaller than 4 pixels across, but it will catch dust devils bigger than that. (Adjust performance optimizations to suit the needs of the down-clocked radiation-hardened CPU used.)

Noise will affect results, but noise can be measured in advance, and be used as a cutoff value, between motion versus no-motion. (i.e. how far away from zero, before motion is declared and video is automatically recorded)

Memory will definitely need to be big enough to hold two uncompressed images, for doing mathematics with at sufficiently realtime speeds.

MER had more powerful processors than 10Mhz, as I understand it (20 MIPS). Plus, memory was most certainly big enough (Something like 128MB). So assuming MSL has better specs, it is well positioned to almost certainly include automatic motion detection software. Even at its slow speeds, MER definitely has a CPU and RAM powerful enough to do motion detection -- if it weren't for the very slow pancam frame capture rate.

Checking every 4th pixel of a 2 megapixel image (4-step horizontally and vertically) only checks 1/16th of the pixels. You'd only need to watch a scant 90,000 pixels of a 2 megapixel image, to detect motion of objects bigger than 4 pixels. (Variables do apply here like noise, how faint the object is, so the object may need to be bigger to compensate for the faintness and still be above noise threshold, but you engineers get the idea of what I am talking about).

At approximately only 5 instructions per pixel (pixel load from X, pixel load from X+1, subtract the two, add result to an accumulator, increment pixel counter to load from next pixel), required for motion-detection mathematics, that's only 450,000 instructions. Plus a few instructions for end-of-row loop counter, and finally the cutoff value check. Let's be generous and throw in a crazy codebloat of 300%, by programming it in C++ instead of assembly, or waitstates caused by radiation-hardened ECC-type memory, etc. That's 2,000,000 instructions. A 20,000,000 instructions-per-second CPU can easily do the math, the same CPU used in the MER's. (At 0.25 seconds, you've got time to execute 5,000,000 instructions.) You can easily see where I am getting at, the MER hardware have specs capable of doing motion detection - if the cameras were able to capture fast enough.

Experimentation will be needed -- you may need to poll the image at different intervals such as -- every 1 second instead of 0.25 second, because the dust devils may not have moved much in 0.25 seconds. This makes it an even easier load on a CPU -- you'd only need to execute 450,000 instructions once a second -- a CPU load of less than 3%. (Or less than 12% for the 'bloated-code' version). In fact, there might even be enough CPU left to execute simultaneous motion detection algorithms for slow and fast moving objects, so that recording begins more quickly for fast moving objects, but still being able to detect slow moving objects or fainter objects.

Motion detection ain't rocket science -- even a high school graduate can do it.

Heck, even I can do it -- and there's no doubt the professional engineers will definitely do motion detection in MSL. It'd be stupid not to inlcude it, if you've got cameras capable of doing 10fps!

I programmed for an open-source realtime image video processor, at www.dscaler.org so I can vouch for what I am saying here. I'm listed in the 'Authors' credits. Go check it out.

[Mark Rejhon]

JPL succeeded in a crude form of motion-sensing on the original MER rovers.

DUST DEVIL MOVIE by SPIRIT MER
http://www.nasa.gov/vision/universe/solars...m/mer_main.html

It is low framerate though, but it shows frames of the same dust devil (and its shadow) in motion.

According to article I read about this, they used some kind of an image combination technique, not too different from what I just described above. Similiar "simple mathematics" is used to determine changed pixels. While not exactly the same algorithms as the technique I described above, and this was done on Planet Earth on a series of 21 thumbnails, that even the 'lowly' MER can successfully capture a movie of dust devils - exercised in actual practice!

If MER can successfully capture a dust devil movie, I see no problem for MSL doing it!



These frames were captured 20 seconds apart. Now, imagine this at 10 frames per second from MSL! That'd be something to see.