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Explaining the Mars Photo Colorization
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."
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!
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?
Aside of the odd colors, I found this one of the most interesting anomalies in the pictures so far.
"Honey, I feel a certain distance between us..." "Really? A 31ms ping ain't that bad..."
>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
It'd be interesting to see the raw image data but I expect that without software manipulation it'd be a pointless excercise.
Worst
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.
We hope your rules and wisdom choke you / Now we are one in everlasting peace
Not to do anything crazy like bring the artcle into the conversation, but the uncalibrated RGB raw data that the mars rover sends back, and the methods used to color correct it reminds me of this:
The Russian Record
This brilliant Russian photographer in the late 1800s/early 1900s took an amazing number of photographs, and he would photograph everything three times, with a red, blue and green filter.
He would then use a special triple projector with the appropriate color filters to show gorgeous color images, long before the invention of color film.
So today, we can put these images back together in Photoshop, but we have the same Mars problem, we have three color channels, but no clear idea how they relate to each other.
Lacking a color-calibration sundial, we have to rely on our knowledge of skin tone, sky color, etc to tweak these colors. The link above has a link to the raw files in the Library of Congress, for geeks who want to recomposite some of their own.
What were you expecting?
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 be affected by colour absorption in the martian atmosphere. Yes it would be an RGB channel image rather than a true human visual image (no digital image can be). But it would be the closest thing to the kind of snapshot a human standing on mars with a digital camera would take. It would be something we could all relate to directly.
I thought that the whole idea with Spirit was to make it anthropomorphic: binocular vision, 1.5 metres tall, mobile, etc. So why not do a couple of panoramas in RGB? Why not look around before launching into the science?
In fact, Spirit has taken a couple of images with L4, but mainly for calibration against the sundial or as part of a test rotation through all filters. Almost all of the component images for the panoramas are taken with L2, L5 & L6, resulting in the present confusion when these are mapped back into an RGB image. So we know the L4 filter works.