ArchAngel's Mars Issues Thread

[ArchAngel]

THE RAVINGS OF A MARS MAN

http://mindspring.com/~madman73/Mars_In_Color.html

I must compliment the mad man who runs this site.

He has done a far better job than NASA at providing us with color images from Mars.

Why is that?


ArchAngel from GLP

[NGR]

Originally Posted by ArchAngel

Why is that?

I really don't know, but I would speculate that the scientists involved are very busy undertaking real science in their quest to understand Mars and its history in the small window of oportunity that the rovers lifespan provides.

The pictures that they provide for the public perusal are simply to satisfy general curiosity and to provide additional publicity for what has been a great achievement. The idea that there is much fuss about the true colour nature of the pictures is probably well off the radar screens of those scientists involved in the undertaking.

Incidently has anyone actually put in a request to NASA to provide such an image?

[ArchAngel]

Let me start by saying I am AArchAngel refered to in the article at ATSNN: Above Top Secret, and am later ArchAngel in the discussion.

I was one of the first to post about this on the internet.

I am also ArchAngel at the infamous GLP(Don't judge me by this), and numerous other forums.

I really don't know, but I would speculate that the scientists involved are very busy undertaking real science in their quest to understand Mars and its history in the small window of oportunity that the rovers lifespan provides.

This brings up many other questions.

Are not the scientists using the raw data in the programs, and applications that they setup before the images started coming in?

Will they not be using this data right away instead of waiting for the panoramas?

I believe any real science work would be done only with the raw data.

All Color images are for the public.

The pictures that they provide for the public perusal are simply to satisfy general curiosity and to provide additional publicity for what has been a great achievement. The idea that there is much fuss about the true colour nature of the pictures is probably well off the radar screens of those scientists involved in the undertaking.

Yes, the images are provided for the public, but as shown on numerous web sites like the one above what they are producing is not color, yet they have the ability to use the L4 in place of the incorrect L2 as the source for these images.

The ones creating the images for the press page can easily provide us with better images by simply starting with the proper data.

I believe that in order to not create a false perception NASA should not have released any color images other than ones created from L4 L5 L6 raw data.

Incidently has anyone actually put in a request to NASA to provide such an image?

NASA commented in forum at ATSNN so they are quite aware of the issue, and there should be no need for asking after everything raised there.

[The Bad Astronomer]

Sometimes color images are useful. In a galaxy, for example, they make it clear where, say, newly-formed stars are versus dust. For Mars, I would think that color might help determine the relationship between dusty and dust-free regions.

But the real science is done with the greyscale data (at least for deep-sky astronomy). It is not really raw, which is what scientists call the data right off the instrument. There is usually some processing that goes on to clean up camera defects and the like. But the cleaned image is then used for analysis.

For Mars, I don't know. It can be difficult to extrapolate from something like Hubble to the way planetary geologists use their data.

[The Bad Astronomer]

And as far as the color images go, my only beef is that people are tossing around the phrase "true color" too casually. There is no such thing as true color. Color depends on lighting, shading, contrast, internal and external factors, and changes continuously for even a single scene.

You can see that the colors of the martian rocks changes with time of day; the sun angle changes, causing the way light reflects to change. The sky changes color with sun angle too, which is most likely due to the way the dust scatters blue light. The amount of dust in the air changes too, making a hash of all this!

Digitial cameras can only come close to reproducing what the eye sees, because the filters don't match the color sensitivity of the cones in our eyes, the detector doesn't match the sensitivity of our eyes, and combining three frames using different filters is a nearly impossible task.

I think it would be nice if the Mars Express, Odyssey, and rover teams had someone (or ones) full time to process the color images, but that would cost big bucks, and they have little money for such things. It sounds silly, when you're spending millions, but I have been involved with projects like this, and you wind up cutting things you really need to fit the budget, let alone stuff like a staff artist/image processing person. Hubble has people doing that, and they do an amazing job, but it's rare in this field.

[ArchAngel]

And as far as the color images go, my only beef is that people are tossing around the phrase "true color" too casually. There is no such thing as true color. Color depends on lighting, shading, contrast, internal and external factors, and changes continuously for even a single scene.

True color, and what NASA is presenting to the public are very different.

Much more different than it needs to be.

They have the data to produce MUCH better color images.

Debate about exact colors should only start from the point of an L4 L5 L6 image.

The frequencies of light represented in the picture for the red channel do not match that of the human eye.

[Archer17]

Originally Posted by ArchAngel

True color, and what NASA is presenting to the public are very different.

Much more different than it needs to be.

They have the data to produce MUCH better color images.

Debate about exact colors should only start from the point of an L4 L5 L6 image.

The frequencies of light represented in the picture for the red channel do not match that of the human eye.

Where did you say you were from again? :wink: Why the nitpick on this? Why even post here? If you don't trust the images, what difference does it make what NASA or any of us say anyway? :-k

[ArchAngel]

Why even post here?

Why not?

Why do you?

I hoped to discuss the issue here.

Someone posting unlogged as Dr. P at GLP commented on the issue in a post of mine, and several people told me it was Phil Plait from Badastro.

I know about the conflict between GLP and Badastro, but I am not here to cause trouble.

If you do not care for my questions do not answer them. I am not trying to impose myself on you.


Had you seen the color images at the Mars Man site already?

What do you think of his work?

What do you think of the apparent blue?

Why is the sky blue?

[Lm Wong]

Originally Posted by ArchAngel

What do you think of the apparent blue?

Why is the sky blue?

Here an explanation from
Mary Urquhart
Laboratory for Atmospheric and Space Physics
University of Colorado at Boulder
and from
Jim Murphy
Mars Pathfinder ASI/MET Science Team
http://quest.arc.nasa.gov/mars/ask/a...thout_dust.txt

More
ftp://ftp.hq.nasa.gov/pub/pao/pressrel/1997/97-148.txt

So it is scientifically possible to have images of a Blue Sky on Mars.
Added
Mars Pathfinder Images - Scroll down :Interesting clouds formations and colors of the atmotsphere-.
http://nssdc.gsfc.nasa.gov/planetary...th_images.html

[Archer17]

Originally Posted by ArchAngel

Why even post here?
Why not?

Nice answer

Originally Posted by ArchAngel

Why do you?

Stupid question. You're on my turf. Do you ask people why they live in their houses too?

Originally Posted by ArchAngel

I hoped to discuss the issue here.

You just bragged about your resume and asked a lot of innuendo-laced questions.

Originally Posted by ArchAngel

Someone posting unlogged as Dr. P at GLP commented on the issue in a post of mine, and several people told me it was Phil Plait from Badastro.

I know about the conflict between GLP and Badastro, but I am not here to cause trouble.

Conflict? Call it the legitimate attempt to teach. When people come over here from there asking if Jupiter will really explode, sometimes education is necessary.

Originally Posted by ArchAngel

Had you seen the color images at the Mars Man site already?

No.

Originally Posted by ArchAngel

What do you think of his work?

I don't think his site is significant in any way, many of the same images are in this forum.

Originally Posted by ArchAngel

What do you think of the apparent blue?

Why is the sky blue?

Someone beat me to it. Do you honestly think Mars has an Earth-like atmosphere? Is this why you're nitpicking?!? #-o BTW, remember when I said you just ask alot of questions? I just answered another volley of them. Start discussing AA.

[edited twice- to change Martian blue sky query (since it was already addressed) and to fix a poorly constructed sentence regarding "Badastro" who wasn't the BA in this case anyway)

[The Bad Astronomer]

[quote="ArchAngelSomeone posting unlogged as Dr. P at GLP commented on the issue in a post of mine, and several people told me it was Phil Plait from Badastro.
[/quote]

Well, asking me isn't so hard.

No, it wasn't me. I only post there logged in, or unlogged as "Badastro(unlogged)". I hardly ever post there anymore anyway.

[Charlie in Dayton]

Why even post here? I do hope that question was asked tongue firmly in cheek...since I showed up here, I've learned more about philosophical processes and Phil's view of the world and science in general (fer cripes sake, we were discussing the physics of why a trombone works the other day!)...I was a hanger-on over at JREF, but for some reason my bent is more the physical than the philosophical...I'm still there, just less so...but I wander...

My take on why the pictures look different may be so far out in left field it's a foul ball...

The explanation in Bad Astronomy of why the sky is blue has its corollary on Mars. The atmosphere is thinner, the chemical composition is different, so there's much less blue scattering, which makes the red more prevalent. Right?

Not to mention that the pictures we're seeing are being taken with cameras that respond to a different spectrum than the human eye, and the rejiggering to get 'em to look like we'd see them probably never will come exactly right, so there'll always be a little bit of 'odd' to them. Frankly, it ain't that much of a big deal to me. Those of the Hoagland persuasion, IMHO, are just looking for something to make them look special..."Look, I caught the gummint leading us astray again!". These folk really need to get a life...

[Archer17]

Originally Posted by Charlie in Dayton

Why even post here?..

In ArchAngel's defense Charlie, that question was posed by me to him (unless this was aimed at me). His "quoting" style obviously is different than what we're used to. While it's not in my nature to discourage anyone from joining our board and posting here, I asked it in the context of his posts, which IMO questioned NASA's integrity and spurned the replies he was receiving from members of this board.

[Glom]

The answer is quite simple. True colour is quite naf. You have to sex it up a bit. You don't think the Pillars of Creation are true colour, do you? Besides, isn't there the Clementine type thing? The wavelengths used to construct the picture aren't just visible wavelengths.

[dummy]

I really don't agree with the site's claim that their 'true colour' images are better than JPL's. I don't even get the logic behind his arguements.

On one page he claims that merging the L4/L5/L6 give 'perfect colour images that look just like theyre supposed to look' (http://mindspring.com/~madman73/Mars_In_Color.html) yet on another page he merges L4/L5/L6 and gets all kinds of wacky colours (http://mindspring.com/~madman73/Mars_In_Color3.html).

He also fails to mention that the SOL003 merged L4/L5/L6 images colour's look totally different than when you merge earlier SOL's L4/L5/L6 images.

There's a thread on here that links a site explaining in detail why perfect 'true colour' images are hard, if not impossible to make. If you're interested: http://www.badastronomy.com/phpBB/viewtopic.php?t=10795

Am I the only one that sees no sense on these endless Mars colour conspiracies?

[informant]

Originally Posted by ArchAngel

http://mindspring.com/~madman73/Mars_In_Color.html

I must compliment the mad man who runs this site.

He has done a far better job than NASA at providing us with color images from Mars.

Why is that?

Why do the rocks look blue in the so-called true color pictures?

[TinFoilHat]

Why does the guy who runs the "true color" site assume that the L4/L5/L6 color filters precisely match the R/G/B channels in the monitor I'm using to look at his sight? That's the only way his images would be actual true color. Otherwise, they're not guarenteed to be any truer than the ones from NASA.

[ArchAngel]

Since I am imposing on your turf I will leave now.

I expected better here.

One last question:

Would you believe that there is some kind of conspiracy if NASA never gets around to producing a paorama with L4 L5 L6 filters, and would you bother to explain it to a novice if the false images were brought up?

[Glom]

Originally Posted by ArchAngel

Would you believe that there is some kind of conspiracy if NASA never gets around to producing a paorama with L4 L5 L6 filters, and would you bother to explain it to a novice if the false images were brought up?

Not really. They'll do it if they need to. Since I don't work on MER, I'm not going to assume dirty doings if I don't understand their needs.

Don't go yet. I'm still not entirely clear on your stance. Would you think there is some kind of conspiracy if there was no such pan?

[Gmann]

A great many people have this fixation on what the true colors of Mars are. They are losing sight of the big picture. What is the true make up of Mars? That is the most important point. The sky could be pink with yellow polka dots for all I care, what is important is this:

Is there water/water ice present, and if so, how much and can we access it?

Are there currently some forms of life on Mars?

Have there ever been life forms, and if so, what was their nature?

Was there ever intelligent life? If so, did they leave behind evidence of their existance?

If Mars was a vibrant living place, what happened to it?

All of these issues, and many others that I have not thought of at this time come into play. Water would be essential if we plan to land a research team on Mars. If there is ice/water that we can get to, it would provide a means of survival, and a means of manufacturing fuel to go back and forth. I seriously doubt that NASA is "hiding something" and I also don't buy the "shadow government" thing either. Keep in mind, if NASA was to announce that they had found evidence of past civilization, that would only serve to advance their cause, and give a good reason to launch a manned, or at least, far more aggressive robotic study. In short, hiding the "truth" would be the most counterproductive thing that NASA could possibly do at this point. Jump off the "true color" bandwagon, and get with the real science, that is where the answers live.

[informant]

Originally Posted by ArchAngel

One last question:

Would you believe that there is some kind of conspiracy if NASA never gets around to producing a paorama with L4 L5 L6 filters, and would you bother to explain it to a novice if the false images were brought up?

That's two questions.

[TriangleMan]

I think that the only way to get the 'true color' would be to wait until the soil is analyzed in detail for composition. Once we know the make-up of the minerals in the soil it would be easy to recreate it on Earth to determine its color. Then, if one was so inclined, they could calibrate the photo colors using the soil color as a 'base line'. Of course one has to take into account the difference in atmospheric absorption of light and so forth between Earth and Mars.

Why is this so important again?

[Amadeus]

I think the reason most people want "true colour" is so the can picture themselfs standing on mars. The term true colour I agree is pointless. I work as a graphic designer and I know colour is subject to a lot of factors including lighting paper stock ink type etc etc. Even real life is not true colour. How do you know that when I look at "Red" i'am seeing the same colour as you? Unless you want NASA to pantone Mars you will just have to take their word for it.

Again, I do not think that for the most part people are asking for "true colour" other than the fact they want to make believe that they are standing on Mars. This is perfectly understandable.

On a related note I quite like stereo gram photos ( the 3D ones where you have to look at two pictures cross eyed ) Has anyone put together any mars versions of theese? I do not have 3D specs and I prefer to see them in colour.

[JimTKirk]

Originally Posted by ArchAngel

THE RAVINGS OF A MARS MAN

http://mindspring.com/~madman73/Mars_In_Color.html

I must compliment the mad man who runs this site.

He has done a far better job than NASA at providing us with color images from Mars.

Why is that?


ArchAngel from GLP

ArchAngel - I think you need to fully read and understand the post that Kano made at ATSNN about the L4, L5 and L6 filters.
http://www.atsnn.com/marscolors.html
As you can see, the L4, L5 and L6 filters DON'T equate to the color absorption of the human eye. That means combining images produced with those filters WON'T produce a "true color" image. The images from each individual filter would need 'tweeking' to rebias to an equivalent wavelength to the human eye before being combined. Mad Man's work doesn't take this difference into consideration and only expects the 'closeness' to be good enough.

[TrAI]

As I understand it, if you merge the L4, L5 and L6 as RGB channels, your picture will not have anything like true colors at all. If I am not completely mistaken the imaging system on the rovers use an automatic gain(This would be automatic adaption of the CCD reference based on the point of highest brightness)/sensitivity(the sensitivity of a CCD can not really be directly altered, but since the energy of every photon that hits a CCD cell will accumulate you can get brighter images by increasing the time the array is exposed before you read it of) system. This means that the most reflective object in the frequency of the current filter will be mapped to white in the grayscale image and the darkest to black. This means that for example a scene that mostly reflects only 1% of the blue light, an object that reflects 2% will be 100% white in a grayscale taken with the L6 filter, something that is quite useful for getting the maximum number of levels in the image. But if you were to combine this with pictures taken with the other filters without first undoing the effects of this, the picture will have much more blue in it than there actually were.

The images on the site linked in the OP shows just this problem, the creator of the site have not corrected for the effects of the automatic gain system when combining the images.

[JimTKirk]

TrAI - You're right! I didn't look down far enough in the webpage about the coloring. So to get a real "True Color" image, the person retouching the images would have to know the light conditions and adjust for them. I also think there would still need to be some adjustment to each image to make up for the filter frequency and the frequency perceived by the human eye.

[dummy]

Yeah I would think you'd need to adjust a lot of things, depending on the camera as well as the image. Things such as the rover camera automatically adjusting brightness and contrast might need to be taken into consideration. Some pictures I noticed in the raw image gallery look a lot brighter than others, even though theyre features that are next to each other:

http://origin.mars5.jpl.nasa.gov/gal...0P2303L6M1.JPG

compared to http://origin.mars5.jpl.nasa.gov/gal...0P2303L6M1.JPG

You really can't begin to make semi-accurate true colour images from the raw data unless you know a lot of detail about when/where/etc the picture was taken. I wish people would just be grateful for the raw images, I know I am. It's not like the mars rover teams have to release anything.

[George]

Originally Posted by JPL article

Before sending cameras to Mars, the team took more than 100,000 pictures in a vacuum chamber on Earth that simulates martian conditions. They experimented with different levels of light entering the lens, depending on the angle of sun or amount of dust in the air. They then fine-tuned the cameras to respond correctly to temperature changes or anything else that might cause the instrument to vary.

From JPL "true color" article ...>>> here <<<

It's a nice article that reassures me they know how to color correct reasonably well. There is still the variable sky color and, possibly, sun color effect that may not allow extremely accurate color rendering. It is unclear, however, which, if any, images that they have given out are their "final" versions.

I think there is no harm at all in questioning an image that looks wrong in color especially if the "sun dial" blue looks bright pink.

Although "true color" is far secondary to the primary scientific purpose, I feel it is still important to make it "real" for the public.

Whenever expectations exceed results, disappointment is likely. Expectations for a true representation of what Mars really looks like are, no doubt, high considering the wonderful resolution exhibited in the images. Most people get acceptable true color from their $200 digital camera which works, essentially, the same. So, this also adds to their expectation. This, of course, is unfair to JPL but I believe that expectation is very real and, somewhat, justified.

Also, I suspect "true color" is still important scientifically but to a lesser degree, of course. For instance, we might learn more about the various light scattering effects due to the different atmosphere.

Maybe the BA (or JPL) could assemble a volunteer "true color" rendering team and dedicate a forum to help out the rendering warriors. #-o

[The Bad Astronomer]

Originally Posted by ArchAngel

I expected better here.

Better than what? Logical explanations with rational, scientific evidence to back them up? A skeptical attitude? That's what this site is all about.

[sarongsong]

"...the Mars rover cameras aren't ordinary digital cameras...All of the rover cameras are, in effect, 1-megapixel monochrome digital cameras. The colors in the pancam images come from a sophisticated set of color filter wheels, and the sweeping panoramas are mosaics of many individual images..."
http://makeashorterlink.com/?R2AC23357