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Explaining the Mars Photo Colorization 210

Posted by CmdrTaco from the worth-a-read dept.
TaddyPorter writes "I've seen stories going around the 'net in regards to NASA editing photos of mars. Mainly, the sundial used for calibration showed different colors than the dial on mars. While a wide range of explanations were taking shape, the Pancam Payload Element Lead for the mission, Jim Bell of Cornell University, was kind of enough to explain the color differences."
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Explaining the Mars Photo Colorization More

Explaining the Mars Photo Colorization

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  • Dont trust this man, he's part of the conspiracy!! (Score:4, Funny)

    by Flounder ( 42112 ) * on Monday January 19, 2004 @09:20AM (#8019905)
    They're really colorizing the pictures from Mars to hide the proof of aliens!!

    Actually, now it makes alot of sense. But that still won't stop the conspiracy kooks from claiming otherwise.

  • Secret NASA photos. (Score:3, Funny)

    by Black Parrot ( 19622 ) on Monday January 19, 2004 @09:22AM (#8019920)


    Supposedly they have a picture of Martians humping Beagle2, but they edited it to look like a plain stewn with rocks.

  • If blue=pink, then green=?? (Score:5, Funny)

    by earplug ( 465622 ) on Monday January 19, 2004 @09:23AM (#8019923)
    If blue appears pink on Mars, what is the real color of the little green guys?
    • If blue appears pink on Mars, what is the real color of the little green guys?

      It's gotta be yellow, why else won't the little bastards show themselves?
    • They're blue in real life.

      CBS made the same mistake with the elves in the Rudolph animated special from 40 years ago.

      Green elves were really blue elves so green martians must really be blue martians, right?
    • "Blue" does not appear "pink" on mars. The *CHEMICAL* they used to make the "blue" chip is "blue" to human eyes in normal lighting conditions because it reflects "a lot of the light in the blue part of the spectrum". The *CHEMICAL* is also "very bright" in the "near infra-red" which is *outside* the range of normal human vision. (Hence "infra-red" and not just "red" 8-).

      The scientists are interested in the near infra-red, and infra-red is way on the other end of the spectrum from blue.

      So they used the

  • Filters vs Bayer (Score:5, Informative)

    by cflorio ( 604840 ) on Monday January 19, 2004 @09:23AM (#8019926) Homepage
    Of Course the colors don't look life like. They are taking multiple exposures with different filters for the colors.

    They could have used a Foveon Sensor [foveon.com] if they didn't want Bayer interpolation.

    • Re:Filters vs Bayer (Score:3, Interesting)

      by Anonymous Coward
      Look, all I want to know is what my eye would see if I were standing on Mars. Can't someone just cut through all this BS "science" and tell me that?

      • red skies vs blue skies (Score:5, Insightful)

        by Alien54 ( 180860 ) on Monday January 19, 2004 @09:48AM (#8020072) Journal
        This controversy has been seen earlier on SlashDot in this story on the Blue Skies of Mars [slashdot.org].

        The questions are, of course,

        1. if there is a tinted color light source, what would the color target display on a normal color target? What would it show via the camera with the tinted light source
        2. The sun is the same light source on mars as it is on earth, therefore it should be easy enough to take a solar spectrum and see what the degree of tinting is.
        3. With an atmosphere at 1% or less of the earth, the spectrum could nearly be the same spectrum as in a vacuum
        4. if the spectrums are essentially similar, then the color targets should be the same, say as on earth or in vacuum, given a clear day without dust and clouds, etc.
        5. Of course,there is also the matter of the end result of different photo filters getting mis interpreted. However, JPL has published some pictures with red skies, and some with blue skies, as this item [enterprisemission.com] from the tin foil hat crowd. This has contributed to the controversy.
        See also this earlier slashdot story on the Mars Sundials [slashdot.org]

        So it looks like this particular annoyance has been around for a while.

      • According to Total Recal, first you'll see everything in a red tint from your own blood, then your head explodes. At least when you cut out the BS science.
    • They could have, by why would they? If you want accurate amd controllable spectral sensitiviy then you need and imager with known response and (preferably dichroic) filters with known passbands. A monochromatic, specially doped sensor with excellent S/N ratio and carefully measured characteristics would seem appropriate for a scientific imager.

      Has it ever occured to you that you own personal current wet dream tech fantasy might have fuck-all to do with NASA's scientific requirements?

  • In conclusion: (Score:5, Insightful)

    by CaptainAlbert ( 162776 ) on Monday January 19, 2004 @09:26AM (#8019946) Homepage

    From end of article (yes, I skipped straight there... :))

    There is simply no point in adding on their site "caution these images are not 100% precisely actual colors" when no digital image is really 'actual colors'.

    Quite. In fact, I'd go as far as to say that NASA expected most of the people who were scrutinising these pictures to have some experience with astronomical imaging, where almost nothing is "true" colour in that sense.

    Personally, I'm in favour of as much rebalancing as it takes to make the images pretty. If they don't make full use of my eye's ability to perceive them, then what was the point of spending all that money obtaining them in the first place? So long as the raw originals are available too, who cares?

    • You should have read the whole thing (Score:4, Informative)

      by NickFusion ( 456530 ) on Monday January 19, 2004 @12:01PM (#8021316) Homepage
      The images are not recolored to "make them look pretty."

      There are two main reasons for the color shifts.

      Reason one, some of the images are taken lower in the IR spectrum, and the pigments on the sundail are desighned to react differently in that part of the spectrum.

      Reason two, all the images sent back have their individual RGB channels normalized, which is similar to using "auto levels" in photoshop.

      But the important factor is this: the sundail has a mirror which shows both the sky & the ground, and has full white & black reagions, meaning that even a normalized image will come through unscathed by color changes. These colors are then used to match colors for the rest of the images.

      Bottom line, the colors we see are as accurate as can be gleaned, not just made up to look pretty.

      (You can test this with digital camera images of your own. Run Auto Level on them (which equalizes the color channels). If there are images that full of color, but have no areas of pure white & pure black, you'll likely get some whacky colors. I have a picture of the Charles river with blue sky, green grass, and purple water)

  • Digicams and colors (Score:5, Interesting)

    by mwburden ( 134847 ) on Monday January 19, 2004 @09:26AM (#8019947) Homepage
    I have a Sonly Clie' PDA with a digicam built in, and it can be used to demonstrate how digicams "see" color differently, especially in the near-infrared range.

    If you go into the camera application and aim the Clie' at an infrared remote control (like a TV or stereo remote), and hit one of the buttons on the remote, the PDA camera will pick up the infrared and actually display it visibly!
    • My T610 sees in infrared too. The thing that surprised me is that the infrared lightsource appeared as white with a slight blue tint. I had assumed the red filter would be more sensitive to IR. Cheap filters I guess.

    • My webcam always shows up infrared as a blue-white glow around the emitter. Kind of amusing.

    • Re:Digicams and colors (Score:5, Interesting)

      by mks113 ( 208282 ) <{mks} {at} {kijabe.org}> on Monday January 19, 2004 @09:52AM (#8020103) Homepage Journal
      All CCDs are particularly sensitive in the IR range.
      Video Cameras and digital cameras have to filter out this sensitivity to get true colour.

      Sony uses this IR sensitivity in their "Nightshot" feature on vidcams. Instead of filtering out the IR component, they use it. It throws off the colour rendition but uses ambient and generated IR to show stuff at night.

      I was at a lodge in Kenya just after dusk, and was told that there was a leopard in at a baited tree across the river. It was too dark for me to make it out, so I set up my camera on a tripod, and quickly had a crowd around the LCD watching a very clear picture of the leopard!

      And I discovered years ago that a CCD vidcam will show the light from a remote. I've used it quite a few times to verify that a remote is actually working.

      • Re:Digicams and colors (Score:2, Insightful)

        by pla ( 258480 )
        All CCDs are particularly sensitive in the IR range.

        True, and the one on the Spirit Rover goes up to appoximately 1100nm.

        However, that does NOT excuse the so-called "color" photos from NASA, nor does the excuse presented in the linked text. Why?

        Simple reason - As the link mentions, the Spirit Rover sees the world through two identical cameras, with a set of 14 (16 with 2 pairs overlapping) narrow bandpass (around 20nm wide) color filters.

        Now, it may well hold true, as per the link, that the blue p
        • You can't just combine grayscale images from the L2, L3 and L5 filters to get a color in between ("true" red).

          They have widely varying response curves all over the visible spectrum. Combining them all will make a huge, lumpy response curve centered somewhere around the red visible, but emcompassing and emphasizing frequencies well outside it!!! It will be completely unrepresentative of what the eye would see on Mars. The same goes for all the other simple mixing he's doing, adulterating the other bands.

          Th
          • You can't just combine grayscale images from the L2, L3 and L5 filters to get a color in between ("true" red).

            For dealing with an emission spectra for a homogenous substance, true, you can't just average 670 and 600 to get 635. True enough.

            For most "real world" reflectively-illuminated objects, composed of a wide variety of different substances, yes, you can. Granted, you'll have gaussian rather than linearly-tapering peaks, but you can get "close enough".


            The filter response for L1-8 are NOT notch

      • Re:Digicams and colors (Score:4, Funny)

        by Keebler71 ( 520908 ) on Monday January 19, 2004 @12:48PM (#8021777) Journal
        Lepoards? Dude, don't you know they can be used to see through womens' clothes? [wired.com]

        Leopards.... I'd expect more from a /. user....

    • My Canon A70 picks up the hotplate on a stove, which appears red to my eye, as a bluish purple [danamania.com]
    • Wasn't there a Sony camera awhile back that could see through clothing because it was ir sensitive? Gave the up-skirt crowd a thrill.
    • For sure I can see the infrared too if I look very closely. It just looks like a very dim red glow, though, nothing interesting.

      Tim

  • Conspiracy theorists (Score:4, Insightful)

    by Eric S Rayrnond ( 739458 ) on Monday January 19, 2004 @09:28AM (#8019959) Homepage
    The bizarre claims of conspiracy theorists just go on and on. If you go to their websites you can read more than any brain can handle. I have read literally dozens of things that ``prove'' the moon landings were faked, for example, and each one is rather easily shown to be wrong by anyone with experience in such things.

    I think the problem here is twofold: we tend to want to believe (or at least listen to) conspiracy theories, particularly to do with space. Also, the evidence is presented in such a way that, if you are unfamiliar with the odd nature of the vacuum of space and of space travel, it sounds reasonable.

    • Re:Conspiracy theorists (Score:5, Interesting)

      by Simon Hibbs ( 74836 ) on Monday January 19, 2004 @09:38AM (#8020016)
      >I have read literally dozens of things that ``prove'' the moon landings were faked, for
      >example, and each one is rather easily shown to be wrong by anyone with experience in such things.

      My favourites are the 'pictures of alien moon bases'. Many of these prove to be blowups of astronomical JPG files. The compression algorithm used in the JPG format introduces artificial distortions in the details of images, so it's not surprising they find all sorts of weird looking shapes when they magnify the pictures.

      Simon Hibbs

      • Re:Conspiracy theorists (Score:5, Funny)

        by fredrikj ( 629833 ) on Monday January 19, 2004 @10:36AM (#8020532) Homepage
        Well, if you zoom in even further, you'll find that everything is made up of tiny squares of different colors. The odd thing about it is that they are COMPLETELY square, as if the moon was built from Lego bricks or something. Clearly there is something going on here.
      • My favourites are the 'pictures of alien moon bases'. Many of these prove to be blowups of astronomical JPG files. The compression algorithm used in the JPG format introduces artificial distortions in the details of images

        By all means, explain what compression artifact in the JPEG algorithm, or natural process occuring on Mars, accounts for the top two images (in the left column, not the Viking contexts) at this [usgs.gov] page, containing raw images from the Mars Global Surveyor dataset.

        Keep in mind that each p
        • Oops, our bad. Mars [i]is[/i] apparently inhabited by giant sandworms several kilometers long.

          Thanks for the correction.
          • Oops, our bad. Mars is apparently inhabited by giant sandworms several kilometers long.

            I did not say that. I only said "organic-looking", not the same as "giant sandworms".

            I don't really think we would have missed something as obvious as very large critters living on the surface of Mars. But, as I asked, do you have any suggestions of what natural, non-biogenic processes would cause such unusual structures?

            Skepticism usually benefits science, and I credit you with that. But sarcasm and does not, s
            • divided into parallel channels by a strong surface wind. It's fairly evident by the even spacing that the formation has a uniform density. I believe the prevailing flow is SW to NE (assuming up is "north") because of a small, secondary ridge of accumulated material on the NE side of the formation. As wind blows particles from the slopes of the channel and down the backside, some is desposited and builds up upon itself on the plateau behind it.

              You can tell its wind-based by the similar bottom-left to top-ri
              • You can tell its wind-based by the similar bottom-left to top-right streaks all over the landscape.
                Very cool, but definitely not organic. You would see this kind of thing at the beach if we have hurricane force winds all the time.

                Ah, many thanks, and I mean that sincerely. You've just provided the single most informative response to a Slashdot comment I've seen this month.

                Alas, having already posted in this thread, I can't mod you up, but, have a token +1 anyway. :-)
        • Curiously organic? Have you looked at the other images of Mars? The "swiss cheese" poles and such? The wind on Mars does some pretty crazy stuff, so to see something like a dome (which i would think is either a) a smoothed-over sand dune, or b) a consequence of the impact) or some ridges in a hill (which are obviously artifacts of the wind) isn't all that surprising. You can call them curiously organic if you'd like, but there are curiously organic things all over Mars and Earth that have nothing to do
    • If you go to their websites you can read more than any brain can handle.
      That's what they want you to think.
    • My favourite was the guy in the 1940s that got sick of the "who really wrote Shakespeare's plays?" theorists. He used a sophisticated deconstructive algorithm (I can't remember what, probably looking for anagrams or suchlike) to "prove" some of the plays were variously written by Gertrude Stein, Picasso and FDR. My dad, an English literature PHD has the official line that the plays were not written by Shakespeare at all, but by someone else of the same name.

  • Little Green Men (Score:1, Redundant)

    by Heem ( 448667 )
    Ya know, this whole mars thing... What if the pictures they are capturing show up with these little green martian men just like in the cartoons... I mean.. do you really think they would tell us? No, of course not - so then whats the point of the whole mission?

  • Great explanation, but why... (Score:5, Insightful)

    by darkstream ( 652288 ) on Monday January 19, 2004 @09:32AM (#8019982) Homepage Journal
    ...doesn't NASA throw the public a bone? This color correction controversy pops up everytime a probe successfully lands on Mars and sends pictures back. One would think that they would have a standard RGB style camera for publicity shots. Chances are they can only afford to put on cameras practical for the mission, but I still believe a better solution could be provided. It probably just wasn't important to them... ;) Perhaps next time a camera could be included that features lens that provide scentific data and that can double as a publicist for NASA - spitting out RGB standard images that require no color correction.
    • A "standard RGB style camera" would a.) have the same problems; although they usually have the color correction built into the firmware b.) would fail because of the extreme conditions (cold, radiation, 10+G acceleration loads, ...)
    • You missed the fact that they do have the filters on their camera for taking standard RGB photos. However, they chose to use the near infrared filter instead of plain ol' red because it is more usefull to them. I for one would be very upset if I heard NASA was wasting bandwidth on publicity photos. That is not what multi-million dollar scientific missions are for.
      • I for one would be very upset if I heard NASA was wasting bandwidth on publicity photos. That is not what multi-million dollar scientific missions are for.

        So what are they for? The advancement of science? But to what end? The betterment of mankind? The thrill of pure knowledge? But then isn't the thrill of a pretty picture just as important?

    • Re:Great explanation, but why... (Score:5, Informative)

      by 1u3hr ( 530656 ) on Monday January 19, 2004 @11:27AM (#8020976)
      Here's a page on The Colors of Mars [donaldedavis.com] written by Don Davis, a "Space Artist and Animator" before the current beat up, which explains all the problems involved in trying to get a "true" colour image. He has examples of what he thinks a man on the spot might see. Elsewhere on his site [donaldedavis.com] he covers other planets and nebulae.

  • Mirror (Score:5, Informative)

    by earplug ( 465622 ) on Monday January 19, 2004 @09:33AM (#8019993)
    Mirror here... [netfirms.com]

  • Mirror! (Score:5, Informative)

    by vidnet ( 580068 ) on Monday January 19, 2004 @09:36AM (#8020003) Homepage
    Here! [vidarholen.net]

  • Bitmapped horizon (Score:3, Interesting)

    by l0wland ( 463243 ) <l0wland.yahoo@com> on Monday January 19, 2004 @09:36AM (#8020005) Journal
    Can anyone explain to me why the horizon of the hi-res images is bitmapped [nasa.gov] ? (beware, pic in link is 12MB in size)

    Aside of the odd colors, I found this one of the most interesting anomalies in the pictures so far.

    • Re:Bitmapped horizon (Score:2, Informative)

      by Anonymous Coward
      That's just an artifact of the JPEG compression that was used on the images.

      • Re:Bitmapped horizon (Score:3, Interesting)

        by l0wland ( 463243 )
        That's just an artifact of the JPEG compression that was used on the images.

        That's what I thought too, until I tried to reproduce that. Try it with Photoshop or another photo-editing app, you will not be able to get a sharp pixelated line like that when using JPEG-compression.

        That should read as: At least I couldn't :-)

    • That's because they're hiding the power lines, and the highway far out back. If you look closer, you'll see one of those rocks has a digital watch on his arm, too..
    • Can anyone explain to me why the horizon of the hi-res images is bitmapped

      The entire image is a bitmap, because that's the way digital cameras work. It's just more obvious when you have a sharp boundary to look at.

    • Re:Bitmapped horizon (Score:5, Informative)

      by Anonymous Coward on Monday January 19, 2004 @10:15AM (#8020321)
      If you look at one of the earlier panoramas (e.g., in grey or the partial ones in colour), it is pretty obvious why -- with the sun present, the range of brightness in the image is extreme, and it is difficult to get reasonable contrast from the ground unless you ignore the sky and over-stretch the contrast until the sky is almost white. It is worse when trying to make an image from a series of differently-exposed tiles. Because the sky is not the most interesting part of the image, and it just takes up extra space in the file, I think they just selected it, cropped it out, and set it to an even shade so it would compress well and not look messy with lots of seams between tiles.

      I'm sure they will make some more full-res colour panoramas that include the sky eventually.

    • Can anyone explain to me why the horizon of the hi-res images is bitmapped?

      Every single pixel in the sky is exactly 0xD6A57A, which is very extraordinarily unlikely in a CCD-produced image. The only obvious answer is that the sky in this particular image was painted out for some reason. The sharp pixels on the horizon are a side-effect of this. (Side note: they could have done a better job of this by alpha-blending a couple of pixels down.) Why they did this, I don't know. I'm sure it wasn't to

    • Can anyone explain to me why the horizon of the hi-res images is bitmapped ?

      Just a guess (IANANE}, but it looks like they cut out the sky and replaced it with a solid color. Instead of using various alpha levels to make it blend properly, they used one-bit transparency, making the line look bitmapped.
    • Can anyone explain to me why the horizon of the hi-res images is bitmapped [stair-stepped] ?

      The truth is out. Mars is made of Legos!

  • Article text (Score:5, Informative)

    by epsalon ( 518482 ) * <slash@alon.wox.org> on Monday January 19, 2004 @09:37AM (#8020011) Homepage Journal
    TOP STORY: NASA Is Not Altering Mars Colors.

    Posted by: Kano
    On: Sun January, 18 2004 @ 03:34 GMT
    This article is a brief summarised explanation of how the PanCam on the Mars Spirit Rover operates, in relation to the strange appearance of the calibration sundial in some pictures. The question was first raised by ATS member AArchAngel, and has been discussed at length in this AboveTopSecret forum thread and ATSNN story:
    thread

    Mars Spirit Rover Picture analysis.

    In this thread I will attempt to summarise my posts to the larger thread.

    What are you talking about?

    Ok, the initial alarm was raised after it was noticed that the color-calibration sundial mounted on the rover, looked quite markedly different in the Mars-Panorama shots compared to its regular appearance.

    Immediately wide-ranging theories began to pop up. At this stage I knew very little of the particulars of the PanCam so I decided to go and see what the Horses mouth had to say. I sent out a swag of emails to the NASA marsrover team, the Athena Instrument team at Cornell University, and the long shot, an email to Assoc. Professor James Bell. Who is the Pancam Payload Element Lead for the mission.

    Now, getting no response from the Athena team, and an automated response from the NASA team. I was amazed and delighted to see that Dr. Bell had indeed taken the time out of his busy schedule to help explain this quirk in the panorama pictures. His email response is below:

    quote:Thanks for writing. The answer is that the color chips on the sundial have different colors in the near-infrared range of Pancam filters. For example, the blue chip is dark near 600 nm, where humans see red light, but is especially bright at 750 nm, which is used as "red" for many Pancam images. So it appears pink in RGB composites. We chose the pigments for the chips on purpose this way, so they could provide different patterns of brightnesses regardless of which filters we used. The details of the colors of the pigments are published in a paper I wrote in the December issue of the Journal of Geophysical Research (Planets), in case you want more details...

    All of us tired folks on the team are really happy that so many people around the world are following the mission and sending their support and encouragement...

    Thanks,

    Jim Bell
    Cornell U.

    Now, as far as the pink tab where the blue one should be, that email is infact the complete answer. But its not easily understandable to the layman. Below I will attempt to explain why this occurs.

    Click here to read comments or post your own.

    Displaying the first 12 replies to this news story...
    Posted by: Kano
    On: Sun January, 18 2004 @ 03:35 GMT
    Digital Cameras

    Firstly, we need to understand how the PanCam, and indeed digital photography in general works.

    Luckily for us we have our good friends at http://www.howstuffworks.com to turn to.

    How Digital Cameras Work

    It would be worthwhile to read the entire article on howstuffworks, for a fuller understanding of the processes at work. But because I know you are all busy (lazy?) I will summarise.

    Basically, the heart of a digital camera is the charge coupled device or CCD. This CCD converts light hitting it into electrical impulses, the brighter the light, the stronger the impulse. Now, CCD's are color-blind. All they do is signal how bright the light hitting them is. All well and good for black and white photography. But for color we need to do more. To get a color-picture. We need to record images via the CCD using a series of 3 filters. A Red filter, a Green filter, and a Blue filter. These are then recombined afterwards to give a color-representation of the picture. (Note, cheaper options like the Bayer filter pattern are often used in commercial digital cameras, but they use interpolation and are subsequently less accurate than 3-filter methods.

    Never True Color

    Quite a big deal has been made o

  • Coloring. (Score:2, Insightful)

    by AmoebafromSweden ( 112178 )
    Well its OK, if Nasa wants to change the colors. No fuzz.

    But can they tell if they do that and also provide pictures with alternative coloring so that the recipient have choice.

    That would seem reasonable to me.

    They can do that, and still Edit away all the alien artifacts...

    • Re:Coloring. (Score:4, Informative)

      by PhuCknuT ( 1703 ) on Monday January 19, 2004 @10:05AM (#8020233) Homepage
      Every single image taken by the rover (raw and not even combined into color images) is available for download from the mars rover website. Check here [nasa.gov].

  • Colorization? (Score:2, Funny)

    by Pedrito ( 94783 )
    I don't know what you guys are talking about. Those colors all look fine to me. Mars looks exactly like it did when I was last there...

  • *sigh* (Score:3, Insightful)

    by Jugalator ( 259273 ) on Monday January 19, 2004 @09:56AM (#8020130) Journal
    Wow, do we really need another thread about article about the infamous Mars colonization. We already discussed this in the last one. It's all about filters used. When blue-according-to-the-human-eye turns extremely red, well, that's obviously when they aren't using a filter to reflect colors as seen by the human eye best, but to enhance other wavelengths. I don't really see what the problem is, and why this of all technical stuff has to be so mysterious.

    The link in the article is of course slashdotted now, so here's another one explaining how a camera on the rover works:

    The Panoramic Camera (Pancam) [nasa.gov]

    Pay particular attention to the last paragraph there.

    • Re:*sigh* (Score:4, Informative)

      by aminorex ( 141494 ) on Monday January 19, 2004 @11:58AM (#8021281) Homepage Journal
      You seem not to understand the issue.

      NASA has a broad spectrum of image data from Mars.
      They could use this data to present a picture of
      Mars as it actually appears, or they could use the
      data to present a picture of Mars which does not
      represent the actual appearance. By making the
      latter choice, they misinform the public.

      In this way, they put themselves in the same class
      with persons who offer misinterpretations of image
      data from the moon landings to argue that those
      landings were hoaxed: Both publications serve to
      misinform an already woefully misinformed public.
      • NASA has a broad spectrum of image data from Mars.
        They could use this data to present a picture of
        Mars as it actually appears, or they could use the
        data to present a picture of Mars which does not
        represent the actual appearance. By making the
        latter choice, they misinform the public.

        Hmm...? But they still do it very often and explicitly tell when they do. Just look at this recently released image for example:

        The rover's first exploration rock [nasa.gov]

        That one is supposed to be "true color" for example. I could
      • NASA has a broad spectrum of image data from Mars.
        They could use this data to present a picture of
        Mars as it actually appears, or they could use the
        data to present a picture of Mars which does not
        represent the actual appearance.

        They certainly can (and occasionally do) manipulate an image to simulates what an imaginary human visitor might see, but you can hardly blame them for preferring to show the real data, which is really more honest.
  • The real reason we've seen no Martians. Nobody knows the proper way to read home pregnacy tests there. They all died out.

  • Once again, this link could be useful (Score:5, Informative)

    by Jugalator ( 259273 ) on Monday January 19, 2004 @10:09AM (#8020267) Journal
    Mars Climate FAQ [nasa.gov]:
    - Why isn't the Martian sky blue like the Earth's? [nasa.gov]

    That page includes images using colors-close-to-what-a-human-eye-would-see-them-as as well.

  • Raw image data (Score:2, Interesting)

    by tr0llb4rt0 ( 742153 )
    It'd be interesting to see the raw image data but I expect that without software manipulation it'd be a pointless excercise.

  • The L4 Filter!!! (Score:2, Interesting)

    by daina ( 651638 )
    Ack! All of this arguing all over the Internet, endless postings and emails to NASA and nobody is asking (or answering) the single relevant question:

    Why isn't the Spirit team using the L4 filter?

    The L4 filter passes light at 600nm, right on the red channel for RGB. Combine that with L5 + L6 and we have a perfect RGB channel image to end all this bickering.

    Yes, it would be a narrower frequency band and less scientifically interesting because of the lack of sensitivity in the near infrared. Yes it would

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