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Earth Mars Space Science

Curiosity's Latest High-Res Photo Looks Like Earth 215

Posted by timothy
from the ocean-front-property dept.
New submitter bbianca127 writes "Curiosity sent a picture down to us, and it looks a lot like Earth. Actually, the picture's color quality has been changed — to human eyes, the landscape would look a lot more reddish. Still, it looks remarkably like the southwestern United States (bringing to mind the Arrested Development quote about how Lucille Bluth would rather be dead in California than alive in Arizona)." Definitely a different sense of the place than the one given by the reddish-brown posters I remember from elementary school.
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Curiosity's Latest High-Res Photo Looks Like Earth

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  • by Anonymous Coward on Thursday August 16, 2012 @11:38AM (#41011853)

    Especially the part that mentions where the photo is from.

    • Really? It says right there its a picture from Curiosity (capital C). You should get out from under your rock more often!

  • "bringing to mind the Arrested Development quote about how Lucille Bluth would rather be dead in California than alive in Arizona"

    no, actually, sorry, not at all

    • by neminem (561346)

      I'm watching that show right now! It's a fantastic show, and it's crazy that I'd never really heard anything about it until quite recently. They're bringing it back for another season next year, too!

      But yeah, that doesn't sound like a particularly memorable line. Nor does it seem to have a terribly large amount of relevance to the topic at hand.

      Arizona does pretty much suck, though. I'll grant that.

    • by FrankDrebin (238464) on Thursday August 16, 2012 @01:01PM (#41013037) Homepage
      No kidding. However, like many Slashdot stories, it does remind us that "Everyone's laughing, and riding, and cornholing except Buster."
  • by Anonymous Coward on Thursday August 16, 2012 @11:39AM (#41011863)

    How much more do we need before the public accepts that it's just a few guys driving around Nevada?

  • third parties? (Score:5, Insightful)

    by Anonymous Coward on Thursday August 16, 2012 @11:41AM (#41011877)

    Why is it that people keep redirecting me to a third party site to see the rover images, in stead of linking to the Nasa source?

  • White-balanced (Score:5, Insightful)

    by neoshroom (324937) on Thursday August 16, 2012 @11:41AM (#41011887)
    That's because that photo is the white-balanced version! A white-balanced photo is what the scene in Mars would look like if you literally took the scene, cut out that whole area of ground, transported it to Earth and viewed it under the Earth's sky.
    • How can we know for sure unless we cut the whole area of ground, transport it to Earth and view it under the Earth's sky?

      • Re:White-balanced (Score:5, Informative)

        by need4mospd (1146215) on Thursday August 16, 2012 @11:51AM (#41012045)
        Science.
      • Re:White-balanced (Score:5, Informative)

        by Sarten-X (1102295) on Thursday August 16, 2012 @11:58AM (#41012147) Homepage

        As much as I love the awesome idea of moving a chunk of terrain between planets, I'm going to shoot for an informative mod and answer the question.

        There is a sundial mounted on Curiosity [nasa.gov], with a few colored stripes on it. Those stripes' colors (red, green, blue, and yellow) were recorded under Earth's lighting, Now that those same stripes are on Mars, their apparent color change in new pictures is the result of Mars' different lighting. By comparing the stripes' pictures, an approprite transformation can be determined, then applied to other pictures to compensate for the change in lighting.

        We are sure because we're assuming that those stripes' actual colors haven't changed significantly during flight or landing.

        • by gknoy (899301)

          The thing is, If I were on Mars, the colors wouldn't look like they look here anyway -- because of the lighting that you mentioned. I'd rather see what it would look like on an alien world in its native lighting conditions, not rebalanced to look like it had our light conditions.

          • Re:White-balanced (Score:5, Informative)

            by Joce640k (829181) on Thursday August 16, 2012 @12:39PM (#41012747) Homepage

            Gee, I wonder if such an image could be available on NASA's web site. Nah, that's unthinkable.

            Oh, wait, here it is: http://mars.jpl.nasa.gov/msl/multimedia/images/?ImageID=4431 [nasa.gov]

          • Re:White-balanced (Score:5, Informative)

            by holmstar (1388267) on Thursday August 16, 2012 @12:55PM (#41012963)
            You would, but geologists wouldn't. They are used to what rocks and minerals look like under our own earthly lighting. As such it makes sense to adjust the color of the image to match earth-normal lighting conditions.
          • by ceoyoyo (59147)

            Actually, you probably would see it more like the white balanced photo than the regular one. Your brain is very good at auto white balance.

            As an example, when you're in the shade on a sunny day, does everything look blue (after the first few seconds)?

            • Re:White-balanced (Score:5, Informative)

              by arth1 (260657) on Thursday August 16, 2012 @01:52PM (#41013747) Homepage Journal

              Actually, you probably would see it more like the white balanced photo than the regular one. Your brain is very good at auto white balance.

              Perceptual re-balancing is very different from absolute colorimetric re-balancing, which is what is used here.
              A late evening shot (which this basically is) looks very different when you balance it against a Gretag Macbeth [wikipedia.org] card than if you balance it according to human perception.

              NASAs goal here is clearly to make the picture as useful as possible to those who study them, not to give the public a "true" image of what we would perceive if we were there. I think there should be room for both.

            • Yup, everything doesn't look green in a forest. Your brain fixes the colour balance immediately.
          • Should be pointed out that human eyes automatically white balance anyway. It's the reason white always looks white to the naked eye, whether under tungsten or halogen light, but look different in photographs.
            • Need to be careful here; what you say happens, definitely, but it's not the eyes that do it. It's one of those "zomg my brain adjusted the data to a known pattern" type things.

              Kind of like a sommelier's nose, you can train yourself to see the differences in white points without having to place swatches next to each other, and it's very useful when switching through several temperatures of light sources for simulation purposes. What sucks is once you do, you can't turn it off. ;)

              A VERY common thing,
          • Quoth TFA:

            The colors in this image are not what a human standing on Mars would see — the presence of dust in the atmosphere would make the scene appear much redder. Instead, the pictures have been white-balanced to show how it would appear under typical Earth lighting conditions. This will help the Earth-centered geologists who are trained to recognize features based on how they look using more familiar light.

          • Yeah, but...

            Like you, I too would like to see what it would look like if I was actually standing on Mars. However, the APOD website [nasa.gov] describes what is probably the same photo as in the Wired article (Surprise! I didn't RTFA yet), which contains this blurb: "Images from Mars false-colored in this way are called white balanced and [are] useful for planetary scientists to identify rocks and landforms similar to Earth." So while you and I might appreciate the novelty of seeing what Mars would actu
          • So you won't ever want to use an electron microscope, IR, UV or X-ray camera, since those don't look natural either...
        • Re:White-balanced (Score:5, Informative)

          by HapSlappy_2222 (1089149) on Thursday August 16, 2012 @01:44PM (#41013619)
          Even on earth we have this issue (I've made a fairly healthy living navigating through color space to color space and light source to light source over the years). People seem to forget that our own sunlight can vary during the day, geographical location, cloudy days, etc, and indoor lighting is the beast with a billion backs. Even your own eyes can betray you, needing a moment to adjust, and often one eye sees color slightly differently from the other.

          Color scientists have had an absolute color and light source standard to measure against (CIE LAB) or 40+ years; Mars (or anywhere in the universe that receives light in the visible spectrum) fits just dandy into this model for color transformations, it's just a bit further away than usual. The less light there is to measure, the smaller the total color gamut will be, but you can extrapolate pretty well, if you don't mind some +/- errors along the way.

          Typically, a true simulation would need several hundred color swatches for analysis, plus an iterative scanning approach to nail down the color gamut points that are furthest away (say, blues could be further off than reds, so require more attention for a transform). Still, for a general "this is approximately how it'd look on Earth" a 4 swatch RGBY spectrum is close enough.

          It's something like the difference of having a precision of tenths to a precision of hundred-thousandths, when all you're doing is counting apples. You may be plus or minus a tenth of an apple, but so what?

          The only thing that's a little surprising is that they didn't include a calibrated black strip, but I suppose they didn't really need to account for the variation between deep shadow areas or very dark objects in this case.
          • by Sarten-X (1102295)

            Fascinating and educational.

            The sundial's stripes are just one of several markings on the rover. I would expect a known black to be somewhere.

            • Also a little interesting: Typically people want to match colors across color spaces; as in "I want my print to look like my monitor!!!".

              This case is the opposite; the goal is to punch the saturation, contrast, and luminescence to that of a randomly chosen Earth standard. We want to take the equivalent of a printed image (small color gamut) and see what it looked like on a monitor (large color gamut) prior to printing.

              In general sweeping terms, this is pretty easy to do, provided an educated guess i
            • by TheGratefulNet (143330) on Thursday August 16, 2012 @02:12PM (#41014075)

              The sundial's stripes are just one of several markings on the rover. I would expect a known black to be somewhere.

              he's busy running the country right now.

              (just a bit of humor, don't take it the wrong way.)

      • I totally agree.
        The next mission must be to return a square kilometer of martian surface, so we can accurately check the colour.

      • Re:White-balanced (Score:5, Informative)

        by necro81 (917438) on Thursday August 16, 2012 @12:19PM (#41012441) Journal
        On the rover are color calibration targets (here is the one for the rover's arm's instruments [nasa.gov]). We know exactly what the colors of those targets are supposed to look like, when imaged by the cameras on the rover, under normal Earth-like lighting conditions. By looking at how those targets appear in the images we get back under Mars lighting conditions, we can do two things:

        1) Learn a lot about the lighting conditions on Mars.
        2) Correct the appearance of images we get back to correct for that Mars lighting.
        • by gsslay (807818)

          I'm color-blind, you insensitive clod! It all looks like lush green meadow to me.

      • I would have said it looks like the empty quarter in Arabia, but I cannot see a single plastic bag, car tire or Coke bottle anywhere, so it has to be Mars after all.
    • Both versions (Score:5, Informative)

      by neoshroom (324937) on Thursday August 16, 2012 @11:46AM (#41011955)
      Here is a page on the MSL's site where you can see both versions of the photo:

      http://mars.jpl.nasa.gov/msl/multimedia/images/?ImageID=4431 [nasa.gov]

      One is white-balanced and one colored. The white-balanced version represents what the scene would look like to human eyes under an Earth sky. The colored represents what the scene would look like to human eyes on Mars.

      The point of using white-balanced photos is that geologists are used to looking at rocks on Earth. So when a geologist wants to judge rock characteristics using color, it helps to white-balance it so the color is similar to what it would be if looking at those rocks on Earth.

      __
    • Re:White-balanced (Score:5, Interesting)

      by jellomizer (103300) on Thursday August 16, 2012 @11:47AM (#41011969)

      Which is useful, because it lets us see things in a more familiar frame of reference. Under the Mars Atmosphere things will look more alien to us making normal stuff seem worthy of extra interest. Making the images more earth like, will help us point out what things are more interesting to look at and what to ignore.

    • How about doing the reverse, i. e. adjust the white-balance of photos taken on earth to look like they were taken on mars? Can this be done accurately if we take the picture of Curiosity's sundial as a martian reference? I think it would be very interesting to see earthly scenes the way they would look on mars!
  • by d3ac0n (715594) on Thursday August 16, 2012 @11:42AM (#41011911)

    While there may be a few color differences, one iron and silicate planet is likely to look much like another when there is no vegetation covering.

  • by Kenja (541830) on Thursday August 16, 2012 @11:43AM (#41011925)
    They use black & white (greyscale) cameras because you can get higher resolution for the size & weight. They then take three photos with different filters to simulate color.
    • by kubernet3s (1954672) on Thursday August 16, 2012 @11:46AM (#41011963)
      ...you mean, like every camera? Ever?
      • by fuzzyfuzzyfungus (1223518) on Thursday August 16, 2012 @12:01PM (#41012189) Journal

        Not really...

        If you don't mind being unable to take color shots of relatively fast moving things, you can use a conventional greyscale sensor, swap color filters between frames, and then crunch the result into a color image(or, if you have the space and don't mind a moderately complex optics package, you can have three greyscale sensors, each with a fixed color filter). If you need a color image within one frame, you use a fixed bayer(or similar) filter and demosaicing. Eats nontrivial resolution compared to the pure greyscale or swapped filters strategy; but you get everything in one shot and fewer moving parts. Then you have the somewhat oddball Foveon approach, where your greyscale sensors are stacked vertically, and use the different rates of absorption in silicon of different frequencies to do the filtering...

        In very broad terms, they all have the 'greyscale sensors and filters' strategy; but there are a fair few ways to go about it. If you count chemical and biological sensors, you are more likely to find sensor elements that are actually tuned to a specific wavelength, rather than filtered to it; but the final image is still a matter of crunching together results from individual elements that are really only giving you intensity data for a relatively narrow slice of frequencies.

    • Curiosity has a high resolution color camera on it.

  • From the summary:

    Definitely a different sense of the place than the one given by the reddish-brown posters I remember from elementary school.

    That's because the picture has been altered to remove the red haze, in order to produce an image that more closely resembles a landscape on Earth.

    From the article:

    The colors in this image are not what a human standing on Mars would see — the presence of dust in the atmosphere would make the scene appear much redder. Instead, the pictures have been white-balanced to show how it would appear under typical Earth lighting conditions. This will help the Earth-centered geologists who are trained to recognize features based on how they look using more familiar light.

  • Earth is a big place. You can pretty much guarantee that any rocky planet will have parts that look like other rocky planets. When will we get any science? We KNOW the place is a reddish, dusty, rocky desert. Move on.

    • by Anonymous Coward on Thursday August 16, 2012 @12:34PM (#41012677)
      Gosh, some guy on Slashdot wants to move on. Hey, everybody! Stop testing the MSL! Forget all the calibration tests. Drop the checkout sequences. No need to make sure anything is working right. This guy said go. Just apply all available current to all the wheels. No, there's no time to make a traversability map. All power to the forward shields! Damn the torpedos! Full speed ahead!
    • by nashv (1479253)

      Seriously, are you trolling or simply do not understand that this IS scientific information about Martian terrain, geology, soil, tectonics, atmosphere etc. With respect to earth, it tells us a lot about the Goldilocks zone's extent. Mainly because the other 2 terrestrial planets - Mercury and Venus don't seem to have terrain like the earth.

      Do you think there is just one kind of dusty, rocky desert?
      Go to the Atacama desert, and then to the Gobi desert, and to the Sahara. Tell me if you think they are the sa

  • by danhuby (759002) on Thursday August 16, 2012 @12:33PM (#41012657) Homepage

    From the article:

    > The colors in this image are not what a human standing on Mars would see — the presence of dust in the atmosphere would make the scene appear much redder. Instead, the pictures have been white-balanced to show how it would appear under typical Earth lighting conditions.

    So the story is that a photo of Mars that has been adjusted so it looks like Earth to make it easier for geologists to interpret... looks like Earth. Wow.

  • by PPH (736903) on Thursday August 16, 2012 @12:34PM (#41012683)

    ... across the middle of the photo is Route 190 through Death Valley. Who do they think they are fooling anyway?

  • by Jeremy Erwin (2054) on Thursday August 16, 2012 @12:37PM (#41012731) Journal

    New Mexico, to be precise [360cities.net], near Albuquerque.

  • by Max Threshold (540114) on Thursday August 16, 2012 @02:00PM (#41013903)
    When the spectrum of ambient light does not match that of "white" light (which is simply the particular spectrum we evolved to perceive), the eye's photoreceptors become disproportionately fatigued, and perception of the light's color drifts toward white. You can experience this phenomenon yourself if you light a room entirely with red party lights. Soon, your red photoreceptors will become fatigued and the colors of objects in the room begin to appear more normal. I think explorers on Mars would experience the same effect. So photos like this are actually how it would look to them.

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