Colorization of Mars Images?

ares2003 writes "There is no scientific reason, why JPL is colorizing Mars in that dull red tint as in their press release images. In the latest panorama image, there is a hint, that they deliberately altered the colors, as the blue and green spots on the color calibration target (the sundial) suddenly converted to bright red and brown. Source of original images: 1, 2 - (for highres replace "br" with "med"). At normal weather conditions, as we have at the moment, there should be a blue sky on Mars and earthlike colors. Furthermore the sky looks overcasted on the pictures as it cannot be considering the sharp shadows on the sundial. If the sky was overcast, then because of diffuse lighting, there would be no shadows. A few years ago, I did an investigation about that very same topic for the Viking and Pathfinder missions."

Comments

Check the links, editors

[shystershep]

For more hard-hitting 'information' from the submitter of this story, visit his website: Alternative Areology and Archeology. Browse his conspiracy theories and check out his evidence of cities on Mars, spaceflight in ancient Indian Literature, and learn the secrets of the pyramids!

Way to go, Michael.

Re:Check the links, editors

[s20451]

Well, the truth is that NASA is well known for changing the colors in images. The spectacular images from Hubble are almost always in false (or exaggerated) color, though this is almost never acknowledged.

Re:Check the links, editors

[TheCarp]

I am quite fammiliar with this effect myself.

About 2 years ago I was turned on to "High definition" face shields for my motorcycle helmet. They have a yellow or pink tint to them. The Shoei ones
being pink.

WHat I noticed was it did cut down on glare and it was not obnoxious at night (just as the salesman had said, "sometimes I think I might be able to see something at nigh tbetter if I lift my sheild, and so I try it, and I never can see it any better")

The thing was colors were so wrong.

Now, 15k miles later, I put on the helmet and don't even notice that its tinted, my brain just instantly adjusts the color and I am off.

-Steve

Re:Check the links, editors

[science_gone_bad]

"I still see red as red, green as green, blue as blue and white as white. At least my brain compensates for the difference in light temperature"

Exactly!!! Incadesent lamps have lots of wavelengths. Florescent lights tend to be heavily weighted to UV due to the phosphor on the bulb and the fact that the gas inside them tends to have a more limited wavelength band. These actually created the light we see. But we don't see bluish objects around us, we see the color as we remember them to be!

I saw an extreme example of this effect in SF at the Exploratorium. They had 2 street lamps one Sodium Vapor and one Mercury Vapor. The Sodium Vapor Lamp puts out only one wavelength of light (Sodium light is the most pure outside of a laser) while the Mecury Vapor lamp puts out lots-o-wavelengths i.e. White light.
Since we see light being reflected from an object, we can only see the frequencies available to us. Looking at a picture illuminated by Sodium will ONLY produce a greyscale image as there's only one wavelength to see, but our minds will interperet the greys as color. Until you look at 1/2 the picuture in Sodium and 1/2 in the Mercury Vapor lamp. All of a sudden that colored picture turned into the pure greyscale that it really was.

Now I cannot drive at night w/o thinking about that....keeps me properly freaked out!!

Re:Check the links, editors

[gando]

The "High Definition" yellow or pink tint does a neat thing I did not know about until my eye doctor told me (those who know more feel free to correct me here).

The short story is that different wavelengths (colors) of light focus on our eye at varying distances. So when you look at multicolored objects your eye has to choose one color to focus on (I think he said red was the most common?). Because you can't perfectly focus the other colors, they are slightly blurry.

You don't notice this until you filter out all colors but one, such as red or yellow in the case of these "High Definition" glasses, goggles, or faceplates. Then everything is close to one wavelength, and appears sharper!

Re:Check the links, editors

[amoups]

Things would look pink outside the room because the effect of "adjusting" to the green-tinted light is to simply no longer see the green as well. Your brain will "suppress" the green, making normal light appear to be pinker.

The issue is not with how much color there actually is, but rather, how much color your brain thinks there is.

It's the same with your olfactory sense, too. Ever been to a movie theater? When you walk in, it smells like popcorn. By the end of the movie, your brain has suppressed the popcorn scent, and you won't notice it.

Re:Check the links, editors

[Dun Malg]

it's alse one reason that sodium-vapor streetlights are used - they emit light at one particular wavelength (yellowy/orange) and give you sharp vision / high contrast lighting.

(Drifting off topic here, but...)
An acquaintance of mine is an EMT and he HATES those lights for that very reason. Apparently it's extremely difficult to tell the difference between blood and other liquids under those lights. Subsequently, they end up having to shine their flashlights around trying to see if it's blood, water, coffee, oil, or whatever soaking some guy's shirt, and even then it's hard to tell.

Re:Check the links, editors

[MidnightBrewer]

So the bit where Mars appears red to the naked eye (not to mention, through binoculars and home optical telescopes) is a NASA conspiracy, too? Am I suppose to understand, based on the logic I've read so far, that Mars is actually blue?

And the purpose for changing the colors to red would be? To prevent everybody from realizing Mars for the tropical paradise that it really is, building rockets in our back yards and leaving the Earth en masse?

That, or they're just out to spite me, because they know blue is my favorite color. Bastards.

NASA does deserve a little mocking, though, because the linked page is obviously designed for high school students following the project, and NASA completely fails to mention that the image is not a true-color image. Anybody who has spent any time working in photo processing can see at a glance that the image color is not the original; cyan highlights on rocks, and whites that bleed into pure magentas and yellows are a dead give-away.

Don't believe should be a blue sky

[justanyone]

Shouldn't there be a red sky? All the dust in the atmosphere is heavily red-tinted due to iron content, by my understanding. Am I wrong? Anyone out there a planetary geologist or actually WORK for NASA?

He he

[bigjocker]

The ammount of gibberish in the mars-news.de site!!!!

Check the final paragraph of this page

Colorization is worth it

[addie]

All of the spectacular Hubble images that have been released over the past few years have been composites of various grayscale images each falsely-colored by whatever elements or wavelengths they represent. The result is a truly spectacular image that is accessible to people who have no interest in what the images actually show, but in just the beauty of the image itself. The exact same thing is true of the Spirit images.

We here on Slashdot rant about NASA budgets, and lack of interest in a manned space program. The only way to increase public interest is by catching their attention. Grayscale images simply are not going to cut it. I see no problem at all in colorizing images if it means more viewers are going to be interested, and therefore want to learn more.

Sure, the purist in me finds it a bit irritating, but as with many things, the pros far outweigh the cons.

To put the conspiracy theories to rest:

[Delphix]

They're probably using a blue filter to block Raleigh scattering. We do a lot of image processing, and it's common to use a blue filter in images where you want sharp detail and aren't as concerned about the proper color. Blue light tends to scatter more because of it's low wavelength. If you don't filter it you can end up with just a haze in your image where you'd otherwise have sharp detail in the image.

So put the conspiracy theory to rest.

Re:Pictures are taken over time!!

[Saven Marek]

I live in an area where there are often dust storms for part of the year.

That makes for a completely different light to that of a day overcast with clouds. generally clouds will completely remove distinct shadows, whereas red dust in the air will give an eerie dull appearance to the light, but keep much of the definition in shadows. Exactly like the mars image shows.

The sky may look "overcasted" but anyone commenting that the cast from a dust storm is anything like that from an overcast cloudy day has rocks in their head. (martian or terran will do either way)

What I'd like to see

[suso]

What I want to see if Mars at night. Why can't they take a few pictures of what the two moons look like from the surface? They always take daytime pictures.

Re:What I'd like to see

[C32]

The rover is solar-powered.
(they're too cautious to use battery power to take relatively useless night images)

Re:What I'd like to see

[DunbarTheInept]

That's hardly the only thing interesting that goes on in the sky. And it's a MINOR thing because it's so rare. In a primative state people are likely to chalk it up to a miracle and not investigate it. The recurring things are what matters.

Astronomy started from two roots: 1 - Trying to make a calendar, and 2 - Trying to navigate outside at night.

Mosaic

[drooling-dog]

I don't know about the colors, but one thing that I did find odd is the obvious and clumsy seams between the component images of the mosaics. I used to work with satellite imagery back in the early 80's, and it was pretty routine to resample the images so that they fit together seamlessly. I wonder why JPL isn't bothering to do that? It's not rocket science, after all...

Re:Mosaic

[kindbud]

It was a couple of weeks before they had produced re-sampled mosaics from the first Pathfinder images. The first release of those images were also hastily stitched together, and showed obvious seams. Give them a little time, they'll release corrected panoramas very soon, I think.

HST Images

[cynicalmoose]

The .jpgs that NASA releases from the HST can't really be called 'false coloured' as they aren't the real data. Let me explain to those who don't spend their lives processing HST data.
The data that comes off the HST is reserved for one year to the requesting individual/organisation (and, yes, this is controversial). But it is nothing like the images that NASA releases for the general public. The HST data comes down in a series of CCD output prints, often with whatever spectroscopy data has been requested, most often as a wavelength/intensity matrix. You can't dump that easily into any image editor; it's just a string of numbers. Equally if you dump all the spectra onto one image you will see a nearly black and white picture. So you select the spectra that interest you, and look for anomalies. The resulting pictures used are of little use to the non-astronomer - they aren't full colour, and are often just 4-bit colour showing intensity of a particular spectrum. The pretty pictures come from working out what looks good and combining it, so all images are 'false colour' in some way or another.

I don't know about the Spirit mission, but I'd guess the same applied

Re:HST Images

[mbrother]

The narrow bands aren't so narrow that the small redshifts of nearby objects (ie. in the galaxy or nearby galaxies) would get shifted out of the band. When working on higher redshift targets, yes, astronomers use filters centered on longer wavelengths as appropriate. For a narrow-band image of a galaxy centered on say, Hydrogen alpha, that line in much more distant galaxies in the image would not be in the filter. This effect is actually used to survey for things like star formation at particular redshifts and can be regarded as a feature rather than a problem. As an aside, there are also "tunable filters" out there using a variety of technologies. The HST tunable filter is called a linear ramp filter, and is centered on a different wavelength in different parts of the image.

No Blue Channel

[psydeshow]

Open that image in Photoshop or similar and it's pretty obvious that aside from the noise there is no blue. If it's a filter on the camera it's set to 100%.

More likely someone turned off the blue channel during processing and liked the way the result looked.

Get a clue

[KilobyteKnight]

Even basic research into the principles of photography would expose one to the fact that the camera doesn't see things the same way the eye does.

Any colors captured on Mars are subject to various elements that would alter color. Such as different atmosphere than Earth, changing atmosphere during day, changing angle of light source, light reflected off surroundings. Even if calibrated against the sundial, changing the direction the camera is pointed will change things.

Mars isn't exactly a controlled environment like a studio.

link to NASA article article on sky color

[bstoneaz]

The Martian daytime sky is generally a butterscotch (yellow/brown) color. See NASA link here: http://humbabe.arc.nasa.gov/mgcm/faq/sky.html

Correct color ballance

[Performer Guy]

As for overcast vs blue sky; dust in the atmosphere would not automatically stop sharp shadows, to do that it would have to be thick enough to completely diffuse the light source. Light on Earth get's scattered a lot in the atmosphere, enough to make the sky look blue, but the shadows are sharp. Turbidity could scatter other frequencies on Mars enough to make it look brown and still leave sharp shadows. So your argument is very uncompelling.

The color correction reminds me that NASA had to correctly set the white ballance on one of the Viking missions based on the appearance of a tube of known color they happened to spot on the lander. There are also a couple of ways of looking at this, there's adjustment for incident light color which may match what we'd perceive and then there's the actual color reflected which doesn't always match what we perceive but is a true spectral representation of the colors reaching the sensor. The first is what's considered normal color ballance, but either may be considered a resonable image. The latter would make the colors on the card very unlike those you'd see under white illumination.

Also bear in mind that some wavelengths of the incident light may be dramatically different than on Earth thanks to the atmosphere & dust (the same problem as above really) and if the spectral response from the color card may such that the resulting image could even be missing information needed to reconstruct the color, (that's actually a bit of a long shot IMHO).

In general the most disappointing thing about these images is the horrible stitching and reprojection that NASA has done. I'm not just talking about the near field where a rotating sensor (off center) might cause problems, but the entire image is awash with geometric missmatches even in the middle distance and out to the Horizon, which is just inexcusable. This really is attrocious image processing and rank amatures on Earth have done better with far fewer resources. NASA is making a complete mess of these images, but mostly it's the geometry that's a mess IMHO. Sood spectral callibration would be good too I agree, but I get the distinct impression that the 'A' team is not working on these puplic release images. Maybe these are just for initial release and they'll tidy the data up with more time & effort.

Re:All color images are colorized

[donheff]

I don't know about that. I took some pictures of Jupiter using a $15 Quickcam through a home made 6" telescope. The video frames are stacked using free software (possibly open source, but I only had the binary). I do not believe the software makes any attempt to alter the colors - it just aligns the frames, averages the exposure, and does some contrast and edge control. What you film is what you get. While my images are not large, and not detailed they certainly show the types of colors and banding we expect from media images. And Mars does have a distinct redish tinge in my photos.

Don Heffernan

NASA panorama with proper color

[KeyholeSeer]

Just downloaded the NASA panorama and adjusted it using Keyhole's custom tools. The color corrected image looks much better after careful color processing. (Here is a smaller version if the original is too large for you.)