New Mars Forums

bolbuyk

Member

From: Utrecht, Netherlands

Registered: 2004-04-07

Posts: 178

Re: Nasa hoax: why?!?

When I look around inside my home, ALL objects are enlightened by yellow lights, so ALL colors are changed with the same yellow-factor: when I make "white-balance", I subtract the exceeding yellow component from all objects I look at, so I don't feel like looking at yellow landscape (but I catually see a yellow landscape into my camcorder, if I don't make white balance!).

But that's the point: You can not simply state that some yellow light is '' added'. The psysical properties of light are more complicated to just correct in this way.

Take the example of a thermometer: When calibrated at some point as zero, this will not garantee that the point 100 (or whatever) is also calibrated. When you calibrate two points, in case of a thermometer, it works well, because the shrinking of the mercury is linear with decreasing temperature. But with thermocouples this is also not the case, so you have to correct over a wide range of values.
Even then we are talking about a 1-dimensional property, not a 3-dimensional like color.

The color-calibration with Venera and Viking was less accurate then was the case with the recently landed Rovers. It doesn't really change the point. Principally it's impossible to reproduce the 'right' color, practically the Rovers do it quite accurate (I think), even more than the Vikings or Veneras.

Marzipan

Banned

From: United Kingdom

Registered: 2004-04-16

Posts: 1

Re: Nasa hoax: why?!?

Hi all

Even amongst us humans, the colours we perceive are specific to the individual (as alluded to in this thread). The orange, pink, red, blue, etc. that I see will be very slightly different to that seen by someone else. I can go to my local DIY store and match a paint colour exactly to another and so can most people, but the colour they are actually seeing is personal to them. Luckily the difference in perception in most situations is extremely small, so pink to me is pink to you, but what 'shade' of pink?
As for the NASA image, I think I remember they described this image as 'enhanced false-color', something they don't normally do with their 'normal' 'dodgy' colour images. So I must agree with some comments on this board that this seems to be NASA saying 'Look, this is a press/public image, it's not a scientific one, we've enhanced the colours/image so that the casual observer can get a grasp of the contrasting terrain... blah'
Anyhow, that's my take on it. NASA give you the 'RAW' (mmm RAW=RAW deal?) images so that you can tinker around. The fact that they put up this image and many other tinkered-around-with images up is fine by me. Think about how many young people look at their website. Every youngster would have an image imprinted of blue skies and orange sands on Mars (actually, I say young people, but it's amazing how many older people know nothing of the MERs, Beagle2, Mars , or some people even Earth). Anyhow...
Also, colour images are made up by black'n'white cameras that, for a lot of the colour images, use filters in the infrared or non-human-friendly wavelengths.

Let us not be too hard on NASA on this point. At least they put two serviceable rovers down there (up there). And even if they couldn't immmediately tell whether they were standing in 'mud' or 'salt' as they did initially, it's a fair effort. Ironically poor ol' Beagle2 could tell you if it was salt and also which supermarket it came from...

Ian

cassioli

Member

From: Italy

Registered: 2004-02-23

Posts: 218

Re: Nasa hoax: why?!?

I am definitely disgusted by NASA public images policy:

http://jumpjack.altervista.org/immagini … A.gif]zoom

I didn't do anything to the original images (1P137165596ESF2019P2357L7M1.JPG and surounding, from http://qt.exploratorium.edu/mars/opport … atorium),I just put them into a ping-pong sequence.

Luca

Cobra Commander

Member

From: The outskirts of Detroit.

Registered: 2002-04-09

Posts: 3,039

Re: Nasa hoax: why?!?

Exact calibrating needs strictly for every color a particular mix of calibration-values. Compromises have to be made. In color-transmitting of television-signals it's even a problem. That's one of the reasons televison-white is a little blueish. But no doubt...... Mars is red!!!

Speaking from experience of a few years in the industry, know what NTSC, the acronym for America's television standard stands for?

Never The Same Color.

Any videographers or editors out there, you know it be true...

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Build a man a fire and he's warm for a day. Set a man on fire and he's warm for the rest of his life.

Josh Cryer

Moderator

Registered: 2001-09-29

Posts: 3,830

Re: Nasa hoax: why?!?

cassioli, you're obviously right about the sky, I don't really see why anyone is arguing against what you've said. Has anyone asked NASA to give us an explaination as to why the skies are clearly edited the way they are?

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Some useful links while MER are active. [url=http://marsrovers.jpl.nasa.gov/home/index.html]Offical site[/url] [url=http://www.nasa.gov/multimedia/nasatv/MM_NTV_Web.html]NASA TV[/url] [url=http://www.jpl.nasa.gov/mer2004/]JPL MER2004[/url] [url=http://www.spaceflightnow.com/mars/mera/statustextonly.html]Text feed[/url]
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The amount of solar radiation reaching the surface of the earth totals some 3.9 million exajoules a year.

Stephen

Member

Registered: 2004-01-16

Posts: 68

Re: Nasa hoax: why?!?

I didn't do anything to the original images (1P137165596ESF2019P2357L7M1.JPG and surounding, from exploratorium),I just put them into a ping-pong sequence.

I'm afraid I don't get your point about those particular images, Cassioli. You have simply stacked together a series of images taken under different lighting conditions.

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Stephen

cassioli

Member

From: Italy

Registered: 2004-02-23

Posts: 218

Re: Nasa hoax: why?!?

Image - time
http://qt.exploratorium.edu/mars/opport … 57L2M1.JPG - Sol 101 - Time 15:48:54
http://qt.exploratorium.edu/mars/opport … 57L3M1.JPG - Sol 101 - Time 15:49:23
http://qt.exploratorium.edu/mars/opport … 57L4M1.JPG - Sol 101 - Time 15:50:8
http://qt.exploratorium.edu/mars/opport … 57L5M1.JPG - Sol 101 - Time 15:51:57
http://qt.exploratorium.edu/mars/opport … 57L6M1.JPG - Sol 101 - Time 15:54:49
http://qt.exploratorium.edu/mars/opport … 57L7M1.JPG - Sol 101 - Time 15:57:41

Maybe you don't remember the first posts of this thread, showing evident image retouoch made by NASA...:

From RAW images:

From NASA:

What I don't understand is why NASA "doesn't like" natural martian sky!
Are there Green Men greeting Opportunity, in the Martian sky?
Is there some unhappy employee at NASA which would like to discredit NASA?
Did somebody at NASA let a coffe cup fall on the PC, so image data were corrupted, so he had to manually repaint the image?...
Was there a searchlight visible in those photos, as the picture was taken at Universal Studios?...

Guys, I really don't know what to think, but those images are clearly retouched, this is a fact. About the reason, I don't know, I'm not an international detective...

Luca

No life on Mars

Banned

From: Newyork

Registered: 2004-02-25

Posts: 50

Re: Nasa hoax: why?!?

NASA don´t hide anything. NASA offer both raw and colored images. Pics looks better with solid colored sky and focus is on Martian surface. These pics are for broad publikum (kids, grandparents for everybody. In research they use raw pics and for more or less entusiastic amateurs NASA realese raw images.

atomoid

Member

From: Santa Cruz, CA

Registered: 2004-02-13

Posts: 252

Re: Nasa hoax: why?!?

NASA don´t hide anything. NASA offer both raw and colored images. Pics looks better with solid colored sky and focus is on Martian surface. These pics are for broad publikum (kids, grandparents for everybody. In research they use raw pics and for more or less entusiastic amateurs NASA realese raw images.

Mars photos look best with the real "natural" sky color!!!!  now whatever that is, im not even so sure anymore!! We know that the angle of the sun has a bit to do with it since you get different refraction and scattering throughout the day, as long as the images you use to do the color reconstruction are in the same timeframe (as Cassioli has done) the reconstruction should be accurate. For some reason NASA is the only outlet that keeps giving us these Pepto Bismol skies, who knows why, it just doesnt compute...

...now what im TRULY FLABBERGASTED about are an aspect of the images that Cassioli brought our attention but which hasnt yet been pointed out. These two images in particular show whats going on. Please look closely at the horizon details in these two images below click on the links for enlargements (yes, these images are served from NASA's own web site!):

Opportunity Sol 101, 15:51:57 Local Solar - PanCam, Left 5 http://marsrovers.jpl.nasa.gov/gallery/ … 7L5M1.JPG] see the big picture:

Opportunity Sol 101, 15:54:49 Local Solar - PanCam, Left 6 http://marsrovers.jpl.nasa.gov/gallery/ … 7L6M1.JPG] see the big picture:

Notice the glaring discrepancy?  At first you might think the photos might be the same area from a slightly different vantage point, as if the rover had moved a bit to get a new view and so the perspective would be the culprit for making part of the crater rim and horizon look differnt from the lower image.

But look closely, line up features and you will tell that these photos are taken from the EXACT same place and only 3 mintes apart. The filenames of the images tell you that they are both from the Left pancam using filters 5 and 6 in exactly the same site number and position. So even if you dont believe your own eyes, the NASA data tells you that there can be NO PARRALAX offset whatsoever between these two photos (no apparent dislacement of features due to changing perspective).  The only thing that has happened is that the lower photo has had its crater rim and horizon EDITED OUT. yes, let that sink in... Thats right, these ostensibly "raw" NASA image has clearly been EDITED FOR CONTENT !!  Someone is DOCTORING the "RAW" images !!  As further evidence to show they are doctored if you open these in photoshop you will see that the extreme left and right pixel columns are zeroed out near the top in contrast with the undoctored (top) image. A simple diff operation reveals that the only main difference between the images is the skyline, all the other features line up perfectly even considering contrast effects due to the #5 and #6 filters used. So, you can see that certain details in the top photo are MISSING in the bottom one since these areas have been removed from the image! In particular, the lower photo has been edited to retain a somewhat natural skyline but of course removing some features in the process to remove the top of the crater rim and part of the horizon, though its not really a very good job and wouldnt take more than 20 minutes or so in photoshop to do, certainly if NASA wants to doctor the MER photos they have the resources and expertise to do a much better job!  but why even doctor these images? it just doesnt compute, what are they trying to hide something? i doubt it, unless a martian popped up out of his crater to wave to us, or someone stepped into the background to fix a terrain feature in the Hollywood studio set they are using for these photos... Anyway, we already have the data they have cropped out in the previous image taken 3 minutes earlier, so they havent hidden anything it would seem... theyve just inexplicably messed with these images. Does NASA have something to gain by doing this? doesnt seem so, maybe someone on the inside is playing a trick or trying to discredit NASA?

You can also compare a http://www.lyle.org/mars/imagery/1P1371 … html]third doctored image which is similarly edited close to the lower image but only a slight difference of horizon.

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"I think it would be a good idea". - [url=http://www.quotationspage.com/quotes/Mahatma_Gandhi/]Mahatma Gandhi[/url], when asked what he thought of Western civilization.

Lars_J

Member

Registered: 2004-02-11

Posts: 82

Re: Nasa hoax: why?!?

That is due to the exposure setting of the shot where the (relastively) bright sky causes the CCD element to "bleed over" vertically into neighborhood CCD elements/pixels.

A good explanation was posted on here: http://mer.rlproject.com/index.php?show … wtopic=211 And here is an example of a smaller "overexposure bleed", this time on the heatshield: http://www.lyle.org/mars/imagery/1P1374 … 1.JPG.html

A little research instead of tin-foil grabbing would be useful sometimes...

Lars_J

Member

Registered: 2004-02-11

Posts: 82

Re: Nasa hoax: why?!?

Oh, and regarding the coloring of the martian sky. There is a simple reason - aestetics.

There are examples of when they don't do it - here is one recent: http://marsrovers.jpl.nasa.gov/gallery/ … ...br2.jpg

Can you see what happens now with the sky? Due to the panoramic camera not taking all the component images of the camera at the same time, the sky conditions/brightness change as the sun moves across the sky. So in the above image we have a sky that clearly looks "patched", since they have two choices when combining panoramas:
A) Match the ground brightness as much as possible or
B) Match the sky brightness.
The choice is of course a no-brainer. So how to fix the sky? Well, since most images don't show much of the sky, it is easier to just mask it out and fill it in with an average sky color.

There really is no sinister motive - honestly.

atomoid

Member

From: Santa Cruz, CA

Registered: 2004-02-13

Posts: 252

Re: Nasa hoax: why?!?

That is due to the exposure setting of the shot where the (relastively) bright sky causes the CCD element to "bleed over" vertically into neighborhood CCD elements/pixels.

A good explanation was posted on here: http://mer.rlproject.com/index.php?show … wtopic=211 And here is an example of a smaller "overexposure bleed", this time on the heatshield: http://www.lyle.org/mars/imagery/1P1374 … 1.JPG.html

A little research instead of tin-foil grabbing would be useful sometimes...

Its a given that pixel bleed due to oversaturation of the ccd occurs and usually it manifests in things like streaks and blotches like as on the heatshield and on metal parts of the rover when they are in the pictures or even on http://www.lyle.org/mars/imagery/2P1356 … l]features in the rocks (was that a glint from a crystal facet? i still want to know).

Having it mask out in a subtle way a signifficant portion of the terrain horizon is a bit more interesting. As can be seen in http://www.lyle.org/~markoff/processed/ … 1.JPG]this color composite of the area in question, the most-removed areas do correspond to areas with more sky in them, leading to greater oversaturation bleed in these areas. Its not a very consistent effect, but i think its true that this is the cause of this phenomenon.

Its likely that this problem is widespread and we just havent noticed this much before since you need a sequence such as this to see it in context. If this oversaturation problem really happens this easily in only certain filters, then we should be able to go back and see lots of these paticular filter images with extreme bleedover like this (http://www.lyle.org/mars/imagery/1P137167255ESF2019P2566L7M1.JPG.html]heres an extreme example), provided the sky is a small part of the image, especially at Meridiani where the contrast between the dark soil and the sky is so extreme, so any image with a thin section of sky has been compromised, especially when, like this image, it has a dark crater interior you want to get a good exposure of.  So that must be whats going on. I dont think NASA has any motive to doctor the images like this.

On the side, why is it that these images are in the aspect ratio they are? they have apparently tried to crop off as much sky as possible to get better contrast of the ground before making the exposure, but also resulting this oversaturation problem for certai filters due to the fact that a small portion of the sky also made it into the images?

As for the SKY KOLOR, they should fill in a "true" Mars sky color based on the composite data from the time the photos are taken, and this is likely to be a range of colors, which of course are compromised due to the above ccd limitation principle. The only source photos we should make composites from to guage sky color (at least to get an accurate idea of the true color of the Martian sky at that timeframe) should be those images that ONLY include sky in them (ok maybe a little ground is ok), since based on the same principle, the true color value of the sky per each filter shot is compromised by the values in the ground effecting how light or dark the sky gets recorded in the resultant exposure for each filter shot (if the sky gets pegged to 255 in one filter due to this ground/sky contrast scenario and another filter doesnt result in a pegged-out sky, then the sky color is compromised). Due to these spectral differences, the ccd guages the sky vs ground values separately for each of the separate filter shots which ends up skewing the resultant composite towards some inaccurate color. There seems no way to compensate for this unless you take the contrast-skewing effects of the ground per each filter shot completely out of the picture and obtain even exposures of the sky.

Gee whiz, I wouldnt have expected such *glaring* limitations with the ccd. This pretty much constitutes a good case-study of the limitations of the dynamic range of these ccd sensors and how much compromised the data is from these sensors due to this effect (as well as compression artifacts among other things (im waiting for the day when they can make a ccd with infinite dynamic range by merely doing photon counts)). I thought we could do much better than this with 21st century technology but i guess not, these are probably the best sensors we have for all the extreme conditions the MERs need to address...

btw, what is "tin-foil grabbing" ?

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"I think it would be a good idea". - [url=http://www.quotationspage.com/quotes/Mahatma_Gandhi/]Mahatma Gandhi[/url], when asked what he thought of Western civilization.

Lars_J

Member

Registered: 2004-02-11

Posts: 82

Re: Nasa hoax: why?!?

btw, what is "tin-foil grabbing" ?

By that I meant your persistance in jumping to conspiracy theory conclusions when there are perfectly reasonable explanations available.

cassioli

Member

From: Italy

Registered: 2004-02-23

Posts: 218

Re: Nasa hoax: why?!?

That is due to the exposure setting of the shot where the (relastively) bright sky causes the CCD element to "bleed over" vertically into neighborhood CCD elements/pixels.

[...]
(http://www.lyle.org/mars/imagery/1P137167255ESF2019P2566L7M1.JPG.html]heres an extreme example),
[...]

What is really strange is the edge between saturated pixels and not-saturated pixels: no shade, just an exact edge-line! Maybe the onboard SW automagically cut away any "wrong pixel", replacing it with a white pixel? I wonder what kind of algorithm can decide when a pixel is "wrong"...

So that must be whats going on. I dont think NASA has any motive to doctor the images like this.

The "extreme example" you linked appears to be quite clarifying . But it's quite... "funny" that a 400,000,000$ machine takes such awful images... :rant:

Gee whiz, I wouldnt have expected such *glaring* limitations with the ccd. This pretty much constitutes a good case-study of the limitations of the dynamic range of these ccd sensors and how much compromised the data is from these sensors due to this effect (as well as compression artifacts among other things (im waiting for the day when they can make a ccd with infinite dynamic range by merely doing photon counts)). I thought we could do much better than this with 21st century technology but i guess not, these are probably the best sensors we have for all the extreme conditions the MERs need to address...

As I already stated in other forums, I really think next rovers should carry a commercial 300$ digital camera to take simple "true-color" snapshots using just ONE ccd for ALL colors... Let's reserve multiple CCD camera for multispectral rocks examinations....

Luca

Palomar

Member

From: USA

Registered: 2002-05-30

Posts: 9,734

Re: Nasa hoax: why?!?

*If you think NASA is trying to f*ck around with our minds, then it is. 

I'm really paranoid about all this.

--Cindy 

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We all know [i]those[/i] Venusians: Doing their hair in shock waves, smoking electrical coronas, wearing Van Allen belts and resting their tiny elbows on a Geiger counter...

--John Sladek (The New Apocrypha)

cassioli

Member

From: Italy

Registered: 2004-02-23

Posts: 218

Re: Nasa hoax: why?!?

Ok, guys, let's summurize results:
Combining replies from this forum and from http://www.badastronomy.com/phpBB/viewt … 64]another forum, and also looking at http://marsrovers.jpl.nasa.gov/gallery/ … 2.jpg]this image and http://www.lyle.org/mars/imagery/1P1371 … .html]this image, it is now clear that:
- NASA deletes original sky from rovers' photos becuase it is not good to see (image 1)
- The image below has not been retouched, it's just the rover camera failure

(See extreme example in the second image linked).

So, in the first case, no "hoax", just "embellishment"  , in the second case no "Hoax", just "failure".

And... yes, we are the same person... 

um3k

Member

From: Ohio

Registered: 2004-05-15

Posts: 1

Re: Nasa hoax: why?!?

They replaced the sky with a single color to eliminate any seams that may be visible. The "white overflow" is simply a characteristic of CCDs. From the cheapest to the most expensive, CCDs do that.