More Mars color controversies.
Robert Clark
Colorization of Mars Images?
Posted by michael on Friday January 09, @02:15PM
from the technicolor dept.
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."
http://science.slashdot.org/article.pl?sid=04/01/09/1724246&tid=
As you can see in this image there are blue and green tabs on the
sundial calibration target:
http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20040108a/PIA05018_br.jpg
But in the released public image the blue and green has inexplicably
changed to red and brown:
http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20040108a/color_panorama_sol6-A6R1_br.jpg
One obvious way where color would be important is if there were
observed green patches on rocks. Since both the temperatures and
pressures within Gusev are within the range to permit liquid water
during the daytime AND the gamma ray spectrometer on Mars Odyssey
showed it to be an area of high water content, this would have
important implications for the life issue. One notes then that the
green target on the sundial has been turned brown in the released
color image.
It is notable also that Gil Levin has argued there were green patches
on rocks at the Viking lander sites:
Color and Feature Changes at Mars Viking Lander Site.
GILBERT V. LEVIN AND PATRICIA ANN STRAAT
Biospherics Incorporated, 4928 Wyaconda Road, Rockville, MD 20852,
U.S.A.
AND
WILLIAM D. BENTON
Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91103,
U.S.A.
Journal of Theoretical Biology, (1978) 75, 381-390.
http://mars.spherix.com/color/color.htm
Levin and his son Ron, a physicist, also propose methods for resolving
the question of the correct colors of Mars:
Solving the color calibration problem of Martian lander images
Ron L. Levin*a, Gilbert V. Levinb
a46 Washington Avenue, Burlington, MA USA 01803
bSpherix Incorporated, 12051 Indian Creek Court, Beltsville, MD USA
20705
http://mars.spherix.com/spie2003/SPIE_2003_Color_Paper.htm
Bob Clark
Michael
"Robert Clark" <rgrego...@yahoo.com> wrote in message
news:832ea96d.04011...@posting.google.com...
> Found this on slashdot.com:
>
> Colorization of Mars Images?
> Posted by michael on Friday January 09, @02:15PM
> from the technicolor dept.
> 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."
> http://science.slashdot.org/article.pl?sid=04/01/09/1724246&tid=
>
>
> As you can see in this image there are blue and green tabs on the
> sundial calibration target:
>
>
http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20040108a/PIA05018_br.jpg
>
> But in the released public image the blue and green has inexplicably
> changed to red and brown:
>
>
http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20040108a/color_panorama_sol6-A6R1_br.jpg
>
If these "scientists" can't even calibrate the color properly, how are they
supposed to
be believed about their investigations and conclusions about Gusev? Also,
that Viking
artice is one of the most badly written things I have ever read. A
grammatical vomit.
james
believe anything that NASA produces in pictures. I gues if here were
little green walking in front t\of the camera they would find some
criticism as it is faked!
james
On 13 Jan 2004 05:58:03 -0800, rgrego...@yahoo.com (Robert Clark)
wrote:
Greg Crinklaw
definition of "proper color balance."
--
Greg Crinklaw
Astronomical Software Developer
Cloudcroft, New Mexico, USA (33N, 106W, 2700m)
SkyTools Software for the Observer:
http://www.skyhound.com/cs.html
Skyhound Observing Pages:
http://www.skyhound.com/sh/skyhound.html
wolfhedd
they?
wolf
"Michael" <M...@telus.com> wrote in message
news:TyTMb.10426$wf1.4961@edtnps89...
Quaoar
> What some people just don't seem to get is that there is more than one
> definition of "proper color balance."
How can one justify for NASA when the published color standards on the
lander itself are modified? This is a scientific expedition, not a
journalistic photo shoot, and the color standards at least should be
faithfully rendered.
Q
Chris L Peterson
Because it isn't the primary purpose of the imager to return "faithfully
rendered" color. The imager utilizes a number of well characterized filters in
order to collect data on the chemical makeup of the rocks and soil. Presumably
some of the images released to date have been adjusted to somewhat resemble the
way the eye would see the scene, but this is hardly a mission priority. Some of
the images may even have been made through filters that make it impossible to
accurately get a "normal" color balance.
Many of the raw images are available in case anyone wants to do their own
analysis. All of the mission data is or soon will be in the public domain, so
nothing is hidden. There may be an embargo period on some of the data to allow
the PIs time to produce the first publications, but there is no way to hide
anything for long (of course, the conspiracy crackpots will believe that not all
the data gets released- just as they probably think this for the Viking,
Pathfinder, and other mission data!)
_________________________________________________
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
Greg Crinklaw
When it comes to a press release it *is* a journalistic photo shoot!
Surely you can see the difference between extracting science from color
images to be published in a scientific journal and a press release...?
Surely you understand that most the real science will be from the other
instruments such as the mini-TES? And surely you understand that there
is no such thing as an unmodified image? The concept of an unprocessed
image is naive and utterly without meaning. A camera does not capture
reality, it merely registers the bias that was engineered into it. The
red channel in the Spirit images is in the IR, for goodness sake. Of
course the colors have been modified. They are modified to better match
what a "standard" human would see (a much more arbitrary standard than
people assume and ultimately meaningless).
The people who are complaining completely discount the effects of
differing monitors and printers on the results they are viewing. I have
seen several images that have appeared in the press that have a
completely different color balance than the images available at the
various JPL web sites.
This is a non issue. It's just something for those small minded dolts
who think they are so much smarter than real scientists to whine about.
If you don't like the colors then you are free to redo them to any
standard you wish. The raw images are available as well as the
engineering data for the cameras. What more could you want?
Michael
"wolfhedd" <wol...@hotmail.com> wrote in message
news:KVVMb.8005$zj7....@newsread1.news.pas.earthlink.net...
> letus not knock their abilities, they made to mars for a safe landing
didnt
> they?
> wolf
>
yeah, you are correct. I am exaggerating but it does make you wonder why all
the colors on that calibration
wheel don't stand out. I noticed that the first time I saw it after the
first images were sent.
David Knisely
> "There is no scientific reason, why JPL is colorizing
> Mars in that dull red tint as in their press release images.
If you don't like the color that the web page shows, go get the images and use
one of the image processing programs and tweak the color yourself. Otherwise,
there is no scientific reason why Robert Clark posted this to
sci.astro.amateur, as it is off-topic there (go read the charter).
--
David W. Knisely KA0...@navix.net
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/
**********************************************
* Attend the 11th Annual NEBRASKA STAR PARTY *
* July 18-23, 2004, Merritt Reservoir *
* http://www.NebraskaStarParty.org *
**********************************************
Doink
If there are NO little green men, the photos are fake. The lack of highrise
buildings and intelligent life forms in these Mars photos proves they were
actually taken in Arizona. And that's why the color tinting is necessary.
"james" <geo...@washington.edu> wrote in message
news:gv5800d0rq9pjg093...@4ax.com...
Kenneth Chiu
Greg Crinklaw <capel...@yahoo.com> wrote:
>The
>red channel in the Spirit images is in the IR, for goodness sake.
Are they really using L2 for the red? Just wondering, do
you know why they don't use L4 instead of L2? It seems to
match the human "red" cone response curve a little better.
http://www.lpi.usra.edu/meetings/sixthmars2003/pdf/3029.pdf
Also, the effective wavelengths for R2 and L2 are off by
one. Is that just a typo, or is there an interesting
scientific reason for selecting that?
Hmm...maybe I've answered my own question. It appears from page 76 of:
http://europa.la.asu.edu:8585/PGG/greeley/courses/pdf/bell_2003.pdf
that the "darkness" of R2 and L2 differ by an order of
magnitude (if I'm interpreting the table correctly). So
maybe their actual goal is to enhance the dynamic range of
the measurements they can do at that wavelength, but to do
that they introduced some slight difference in wavelength as
a side effect.
Ron Miller
"Greg Crinklaw" <capel...@yahoo.com> wrote in message
news:100870t...@corp.supernews.com...
> What some people just don't seem to get is that there is more than one
> definition of "proper color balance."
And, of course, they are looking at images processed probably pretty quickly
for press and web distribution---and I, for one, know better than to trust
colors I see on the web.
RM
Alexander Avtanski
Robert Clark wrote:
> [...]
> As you can see in this image there are blue and green tabs on the
> sundial calibration target:
>
> http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20040108a/PIA05018_br.jpg
>
> But in the released public image the blue and green has inexplicably
> changed to red and brown:
>
> http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20040108a/color_panorama_sol6-A6R1_br.jpg
> [...]
Have you ever seen how the colors change if you are under colored light?
If not, the next time you are under one of these yellow street lamps,
look around. The colors you see have nothing to do with the "true"
colors. Threes look brown, reds look very light pink, while light blue
may look almost black.
One thing that maybe is happening here (I'm not saying it is, but this
is just the first thing that comes to mind) is that the light coming is
not "white" but reddish. This would change the colors on the
calibration target just the way we see them.
So I don't see any inconsistency in NASA images. Maybe there is
some additional calibration to be done, but for me it looks fine.
Regards,
- Alex
Robert Clark
From: "David Knisely" <ka0...@navix.net>
Newsgroups: sci.astro,alt.sci.planetary,alt.astronomy,sci.astro.amateur
Sent: Tuesday, January 13, 2004 1:41 PM
Subject: Re: More Mars color controversies.
> Robert Clark wrote:
>
> > "There is no scientific reason, why JPL is colorizing
> > Mars in that dull red tint as in their press release images.
>
> If you don't like the color that the web page shows, go get the images and use
> one of the image processing programs and tweak the color yourself. Otherwise,
> there is no scientific reason why Robert Clark posted this to
> sci.astro.amateur, as it is off-topic there (go read the charter).
> --
> David W. Knisely KA0...@navix.net
> Prairie Astronomy Club: http://www.prairieastronomyclub.org
> Hyde Memorial Observatory: http://www.hydeobservatory.info/
This question is a propos to sci.astro.amateur because it had been
contended that the bluish and greenish areas seen on Mars by amateur
and professional astronomers for centuries were an optical illusion.
It is my contention that not only are the blues and greens seen on
Mars real but they important to understanding the mineralogy and/or
biology of Mars, the Multi-Colored Planet.
Bob Clark
********************************************************************
From: Robert Clark (rgrego...@yahoo.com)
Subject: Re: Mars, the "Greenish" Planet?
Newsgroups: sci.astro, alt.sci.planetary, sci.space.history,
sci.astro.amateur, rec.arts.sf.science
Date: 2002-12-12 21:05:45 PST
David Knisely <KA0...@navix.net> wrote in message news:<3DF8DFF0...@navix.net>...
> Robert Clark posted:
> > Below I discussed the fact that Mars frequently presents a greenish
> > tint to Earth bound observers. This had been attributed to an optical
> > illusion but the best Hubble image taken of Mars also showed areas
> > with a greenish hue:
>
> Its still pretty much an optical illusion of "color contrast". If you
> sample the image with a paint program, most of those darker areas are
> more of a bluish-grey or brownish than purely green. This kind of
> contrast effect has been known for a very long time. Not long ago, I
> fooled a University professor by creating my own "Mars" using various
> grey tones and the ocre and pinkish-salmon colors Mars shows. He too
> though the areas I had painted in grey were slightly bluish-green (and
> he is someone who observes Mars regularly).
>
> > Now the THEMIS camera on Mars Odyssey also shows an area on Mars with
> > greenish patches:
> >
> > PIA03738: Candor Chasma on Mars, in Color
> > http://photojournal.jpl.nasa.gov/catalog/PIA03738
>
> Any "greenish" patches in the jpeg image look like poor color frame
> registration on the part of the person who did the color processing of
> the images (a few tiny light green spots which parallel other detail).
> The gif image doesn't show the same ones, although it does show hints of
> lost data in some strips for at least one of the three colors. The tiff
> image is the most true, as it does show the effects of a loss of data in
> one or two "strips". The image is also a little too dark and contrasty
> for my tastes. Mars has a much lighter color in the telescope. In any
> case, there appears to be little unusual in the image.
> --
The TIFF image on my computer still looks to have greenish patches
on my computer. You can easily verify these areas are actually green
by opening it up in a program that allows color histograms such as
Photoshop. However, the problems registering the different filter
images from THEMIS into a single image have been discussed on
sci.astro. It creates a kind of color "banding" effect. I've been
informed that the ASU scientists are confident of the colors in this
image however.
I'm fairly certain that the Hubble image of Mars has been checked by
spectrograms, i.e., areas that appear green in the image really do
reflect most strongly in the green part of the visible spectrum. I say
this because the scientists mentioned in the news release are involved
in taking visible, near-infrared and infrared images of Mars. You can
contact them if you have questions about this.
I should mention I've seen another explanation of the green areas
aside from the obvious biological one: that it's due to the olivine
that has already been detected on Mars:
A Dry "Green" Mars?
by Melanie Melton
"What happened to the Red Planet? Researchers with the United States
Geological Survey (USGS) now think that about one million square miles
of Mars might be GREEN."
http://www.planetary.org/html/news/articlearchive/headlines/2000/drygreenmars.html
New Evidence Suggests Mars Has Been Cold and Dry
"Red Planet" Abundant with Green Minerals.
http://speclab.cr.usgs.gov/mars.press.release.10.2000.html
The greenish areas in this image should be within the 100 meter
resolution scale of THEMIS to detect olivine if it is there.
Note also that green and blue areas on Mars were also observed in
Viking orbiter color imaging:
Title: Physical properties of Meridiani Sinus-type units in the
central equatorial region of Mars
Authors: Strickland, Edwin L., III
Journal: In Lunar and Planetary Inst., Workshop on the Martian Surface
and Atmosphere Through Time p 144-145 (SEE N92-28988 19-91)
http://adsabs.harvard.edu/cgi-bin/bib_query?1992msat.work..144S [full
text]
Bob Clark
************************************************************************
Search Result 1
From: Robert Clark (rgrego...@yahoo.com)
Subject: Re: Mars, the "Greenish" Planet?
View: Complete Thread (155 articles)
Original Format
Newsgroups: sci.astro, alt.sci.planetary, sci.space.history,
sci.astro.amateur, rec.arts.sf.science
Date: 2002-12-22 14:30:15 PST
"DustyMars" <jdb_...@yahoo.com> wrote in message news:<atvg4i$33c9v$1...@ID-150279.news.dfncis.de>...
> Well, you are dead wrong. But I suppose you are an expert Mars observer as
> well as CCD imager. Maybe you should read a bit on what makes up images.
> Mars is red, period. No green is either seen nor imaged from Mars. Even a
> simple photograph color separation shows this effect. We have only
> demonstrated this effect thousands of times over the past 40 years. As I
> posted before -- read Bill's article.
>
> DustyMars.
>
> ...
From "What's New on Mars," by William K. Hartmann, Planetary Science
Institute, Sky & Telescope, May, 1989, p. 471-475:
"But it was the mystery of the Martian colors that really fascinated
me. The bright deserts all had about the same color, a pale orange
like what you might find at the junction of orange sherbet and vanilla
ice cream. But what of the dark markings? Try as I might. I could not
see them as reddish, brownish, or even grayish-brown. I would look at
them and think "brown" or "green" or "olive," testing my perceptions
against the words. But none of those colors worked. To me, Mars' dark
areas looked rather bluish-gray.
"Based on my pencil sketches and notes at both telescopes, I made the
painting shown here to record my impression of Mars' appearance. And
in doing so, I was amazed to discover that I could demonstrate an
effect that seems to explain the perplexing Martian colors. It is
called simultaneous contrast: if a nearly neutral area is placed on a
strongly colored background, it will be perceived as taking on the hue
complementary to the background. Mars apparently offers us a textbook
display of this. In my painting, delicate shadings of neutral
gray-brown are distributed across a featureless orange background -
but to the eye they take on complementary tinges of pale blue."
...
"Simultaneous contrast was one of several effects suggested decades
ago to explain the Martian colors, and now I suspect it is the major
reason why telescopic observers report greenish and bluish markings on
Mars."
p. 474
Note he is explaining here the visual appearance of Mars for an
observer looking through a telescope, not photographic or
spectrographic images of Mars.
A web search on Google also reveals that "simultaneous contrast" is a
psychological effect due to how the human visual system perceives
color.
Note: it is possible that staring at a photographic image long enough
could cause the simultaneous contrast optical illusion to be perceived
by someone. However, it is clear that is not the origin of the
greenish areas seen in these images:
Hubble Captures Best View of Mars Ever Obtained From Earth
http://oposite.stsci.edu/pubinfo/pr/2001/24/
PIA03738: Candor Chasma on Mars, in Color
http://photojournal.jpl.nasa.gov/tiff/PIA03738.tif
You can easily verify that the green areas in these images actually
are green by using one of the image processing programs that allow
color histograms such as "Adobe Photoshop", or the shareware "Jasc
Paint Shop Pro", or the freeware "the Gimp".
However, Hartmann in his article does rather imply that telescopic
imaging and Viking orbiter images did not see bluish or greenish areas
on Mars:
"A long standing puzzle about Mars is the difference between what
visual observers report and what spacecraft and spectral measurements
indicate is really there. Consider, for instance the planet's color.
For decades visual observers have described the dark markings as
greenish or even bluish, while spectroscopists have claimed that the
dark areas are actually grayish-brown.
"The Viking landers did not show us images of the bedrock outcrops or
gravel plains that probaly create Syrtis Major and other dark regions.
But they did show us lava boulders with the normal brown colors of
weathered basalts. With the Viking data in hand, no one can believe
the Martian darks areas are fields of green bushes or blue lichens.
Plateaus of blue-green rock seem similarly unlikely."
p. 474
Hartmann's statements here are rather misleading. variable "Blue
clearings" in the Syrtis Major region of Mars have been imaged through
blue filters for decades, which implies this area sometimes reflects
most strongly in the blue part of the spectrum. It's seasonal
variability led some to suggest it was due to vegetation. Others
suggested it was due to a variable dust cover. Another suggestion was
that it was an atmospheric effect. Whatever its cause, it is real.
Also, Hartmann only mentions what the Viking LANDERS observed, which
were not in the regions asserted to have bluish or greenish areas.
From these observations alone you can't assert what would be the color
of Mars globally!
In fact the Viking ORBITERS did observe bluish and greenish areas on
Mars:
MAPPING UNIQUE SPECTRAL MATERIALS IN VALLES
MARINERIS.
Lunar and Planetary Science XXX.
"Within the canyons and surrounding terrains, strong
evidence for variable mafic mineralogy in low albedo
units, variable states of hydration or apparent water
content of the soils, and unusual spectral properties
associated with anomalous color in Viking orbiter
images have all been identified [3,4,5,6]."
"Extensive examination of spectra from the Valles
Marineris region reveals many occurrences of materials
that differ in important but subtle ways from the more
common materials in the scenes. For example, [6]
showed that ISM spectra for a region of anomalous
Viking color in western Candor Chasma exhibited a 1 mm
absorption broadened to shorter wavelengths,
consistent with a surface enriched in crystalline
hematite."
"The ISM data have been co-registered to a Viking
Orbiter MDIM to provide essential context for the
relationship to surface morphology. In addition, red-
green-violet color images were used to provide
visible-color information. In the valley floor of Eos Chasma,
the Viking color data show that much of the floor is
covered by a relatively gray material. Some regions of
the valley floor have a distinct relatively blue
color, while the plateau plains are slightly brighter but
with color that is between gray and blue."
http://www.lpi.usra.edu/meetings/LPSC99/pdf/1484.pdf
Syrtis Major Hemisphere - Orthographic Projection
-------------------------------------------------
The image files contained in the SPECIAL/347SO sub-directory are
global
mosaics of the Syrtis Major Hemisphere of Mars. The original images
were
acquired during orbit 1,347 of Viking 1 on March 6, 1980.
The images were acquired during early northern summer on Mars
(aerocentric solar longitude = 75 degrees). The center of this image
is
near latitude 7 degrees, longitude 315 degrees, and the limits of this
mosaic are approximately latitude -60 degrees to 60 degrees and
longitude 260 degrees to 350 degrees.
The images are in an orthographic projection with scales of 1/4
Degree/Pixel (14.8 KM/Pixel, MC* files), 1/8 Degree/Pixel (7.40
KM/Pixel, MD* files), 1/16 Degree/Pixel (3.70 KM/Pixel, ME* files),
1/32
Degree/Pixel (1.85 KM/Pixel, MF* files), and 1/64 Degree/Pixel (.925
KM/Pixel, MG* files). The MG* files contain selected sub-areas of the
mosaic.
The large circular area with a bright yellow color (in this rendition)
located in the upper left area of the image is known as Arabia. The
boundary between the ancient, heavily-cratered southern highlands and
the younger northern plains occurs far to the north (latitude 40
degrees) on this side of the planet, just north of Arabia. The dark
blue
area to the right of Arabia, called Syrtis Major Planum, is a
low-relief
volcanic shield of probable basaltic composition. The bright yellow
area
to the right of Syrtis Major is Isidis Planitia, an ancient impact
basin. Bright white areas to the south, including the Hellas impact
basin at lower right, are covered by carbon dioxide frost.
Image Processing by Jody Swann/Tammy Becker/Alfred McEwen, using the
PICS (Planetary Image Cartography System) image processing system
developed at the U.S. Geological Survey in Flagstaff, Arizona.
http://www.msss.com/mars/pictures/usgs_color_mosaics/347.jpg
Title: Physical properties of Meridiani Sinus-type units in the
central equatorial region of Mars
Authors: Strickland, Edwin L., III
Journal: In Lunar and Planetary Inst., Workshop on the Martian Surface
and Atmosphere Through Time p 144-145 (SEE N92-28988 19-91)
Abstract
Classification and mapping of surficial units in the central
equatorial region of Mars (30 degrees N to 20 degrees S, 57 degrees E
to 75 degrees W) using enhanced color images and Mars Consortium data
identified four major color/albedo units in the dark, reddish-gray
regions that form the classical dark albedo markings of Mars,
including Meridiani Sinus. The darkest, least red (relatively 'blue')
materials form splotches (some with dune forms) in craters,
inter-crater depressions, and part of Valles Marineris. These form the
'Dark Blue' Meridiani unit. Abundant materials that have higher
albedos and are somewhat redder than the 'Dark Blue' unit have
uniquely high green/(violet + red) color ratios in Viking Orbiter
images. These materials, named 'Green-blue' Meridiani surround and mix
with 'Dark Blue' Meridiani patches and are abundant on crater rims and
local elevations. Discontinuous, patchy deposits with still higher
albedos and much redder colors have morphologies classified of the
Type Ib bright depositional dust streaks and sheets that were
classified by Thomas et al. These dust deposits, which appear to be
optically thin and patchy and are darker and not as red as other Type
Ib dust deposits on Mars, and their Meridiani substrates, were
designated the 'Red' Meridiani unit. Distinctive deposits that form
highly eroded mesas and escarpments in northern Meridiani Sinus were
named 'Light Blue' Meridiani, since they are not as red as other
materials with moderately high albedos. Large areas dominated by these
units form Meridiani Province in the central equatorial region of
Mars.
http://adsabs.harvard.edu/cgi-bin/bib_query?1992msat.work..144S
[full text]
Bob Clark
*************************************************************************
Robert Clark
PST, 5pm EST today on the Exploratorium web site:
Exploratorium: Journey to Mars.
http://www.exploratorium.edu/mars/webcasts.html
According to a discussion on a Mars Society list, he may discuss the
Mars color question.
These webcasts are archived so you can view the video at a later date
if you miss it.
Bob Clark
--------------------------------------------------------------
For email response, send to same userid as above, but append
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rgrego...@yahoo.com (Robert Clark) wrote in message news:<832ea96d.04011...@posting.google.com>...
David Knisely
> This question is a propos to sci.astro.amateur because it had been
> contended that the bluish and greenish areas seen on Mars by amateur
> and professional astronomers for centuries were an optical illusion.
You stated *nothing* about amateur astronomers or their observations in your
posting. Your rantings are directed at NASA (ie: unsubstantiated "hints" that
they deliberately altered the color balance of the images to further some sort
of hiddgen agenda). The images looked fine on the TV in the press conference,
but are a little dark on my computer monitor, so obviously, various media are
not compensating in a uniform manner. Again, if you don't like the colors,
get the images yourself and process them yourself. They looked fine on the TV
in the press conference, but are a little dark on my computer monitor, so
obviously, various media are not compensating in a uniform manner.
--
David W. Knisely KA0...@navix.net
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/
**********************************************
Robert Clark
> ...The images looked fine on the TV in the press conference,
> not compensating in a uniform manner. Again, if you don't like the colors,
> get the images yourself and process them yourself. They looked fine on the TV
> in the press conference, but are a little dark on my computer monitor, so
> obviously, various media are not compensating in a uniform manner.
> --
> David W. Knisely KA0...@navix.net
> Prairie Astronomy Club: http://www.prairieastronomyclub.org
> Hyde Memorial Observatory: http://www.hydeobservatory.info/
>
http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20040108a/PIA05018_br.jpg
Remember this is the image of the calibration target *on Mars*. The
blue and green tags are clearly visible as blue and green.
Compare to this image which ALSO shows the Martian surface and sky:
http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20040108a/color_panorama_sol6-A6R1_med.jpg
The blue and green "calibration" tags are no longer blue and green,
but rather red and brown.
S.D.C.
You saved me the trouble of responding to this ridicules thread!
If I didn't have conspiracy crackpots, I'd have little to laugh at.
Shawn
P.S. Your software is excellent!!
Greg Crinklaw
> This question is a propos to sci.astro.amateur because it had been
> contended that the bluish and greenish areas seen on Mars by amateur
> and professional astronomers for centuries were an optical illusion.
> It is my contention that not only are the blues and greens seen on
> Mars real but they important to understanding the mineralogy and/or
> biology of Mars, the Multi-Colored Planet.
The colors on the surface of mars are well studied and documented.
Please read the literature on the subject rather than engage in baseless
speculation.
OhBrother
"Alexander Avtanski" <avta...@ispwest.com> wrote in message
news:bu1ka...@enews2.newsguy.com...
As a matter of fact, during a recent trip to San Diego during the fires, I
was amazed at the different color schemes around me depending upon how much
smoke and what was in the smoke during the week I was there. As I
understand things, the atmosphere on mars has a lot of very fine dust
particles and that being the case, I'm not at all surprized that the
resulting hue, coupled with a dimmer sun makes for some different colors
than we are accustomed to seeing.
Of course, perhaps NASA may *actually* be participating in a huge coverup by
masking the true "pinks and purple polka-dots" that any self-respecting KoOk
would see on the surface, behind every martian cactus and stained-glass
long-abandoned city (which coincidentally is hurriedly air-brushed out
before press conferences).
Or maybe this is all being contrived on a sound stage in central america....
Ya never know in an election year...
O'
>
Robert Clark
used for the sundial calibration image, where the Martian sky and
surface are not visible. But the near-infrared filter giving an
incorrect color to the sundial blue and green calibration targets as
well as to the Martian sky and surface was used when the sky and
surface WERE visible in an image.
Bob Clark
--------------------------------------------------------------
For email response, send to same userid as above, but append
Hotmail.com instead of Yahoo.com.
--------------------------------------------------------------
"Greg Crinklaw" <capel...@yahoo.com> wrote in message news:1008e63...@corp.supernews.com...
lord freepness
>
> Colorization of Mars Images?
> Posted by michael on Friday January 09, @02:15PM
> from the technicolor dept.
>
> 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.
It's a shame that Richard Hoagland www.enterprisemission.com went
and got into trying to convince George Noorey on www.coasttocoastam.com
a recent C to C AM broadcast that the rocks shown on the Martian
surface were "alien artifacts". He blew all his credibility right out of
the
water when he started this rant, then later in the week, tried to shift the
topic to the NASA/JPL "colorization" of the Mars Rover Imagery.
My uncle, who was a crime scene photographer for a major city
police department for 30 Years, always said: "..a color shifted
photo is a faked photo, such is not court admissible evidence, nor
will it ever be anytime or anywhere".
Chris L Peterson
<boing...@amishonline.com> wrote:
>It's a shame that Richard Hoagland www.enterprisemission.com went
>and got into trying to convince George Noorey on www.coasttocoastam.com
>a recent C to C AM broadcast that the rocks shown on the Martian
>surface were "alien artifacts". He blew all his credibility right out of
>the
>water when he started this rant, then later in the week, tried to shift the
>topic to the NASA/JPL "colorization" of the Mars Rover Imagery.
Well, then, it cost him nothing since he had (and has) zero credibility anyway.
>My uncle, who was a crime scene photographer for a major city
>police department for 30 Years, always said: "..a color shifted
>photo is a faked photo, such is not court admissible evidence, nor
>will it ever be anytime or anywhere".
That's a crock! If so, B&W photos would be inadmissible. Photos taken with
daylight film under fluorescent lights would be inadmissible. Photos taken under
unusual lighting conditions would be inadmissible.
Carl R. Osterwald
Peterson <c...@alumni.caltech.edu> wrote:
> On Tue, 13 Jan 2004 17:44:15 -0500, "lord freepness"
> <boing...@amishonline.com> wrote:
>
>
> >It's a shame that Richard Hoagland www.enterprisemission.com went
> >and got into trying to convince George Noorey on www.coasttocoastam.com
> >a recent C to C AM broadcast that the rocks shown on the Martian
> >surface were "alien artifacts". He blew all his credibility right out of
> >the
> >water when he started this rant, then later in the week, tried to shift the
> >topic to the NASA/JPL "colorization" of the Mars Rover Imagery.
>
> Well, then, it cost him nothing since he had (and has) zero credibility anyway.
That is correct. In addition, Hoaxland has claimed for years that the
reddish-hued skys in the Viking and Pathfinder photos were part of an
alleged NASA conspiracy to hide the truth about Mars. All it shows is
that Hoaxland has no understanding of aerosol scattering.
-=-=-=-=-
N8IE
"Robert Clark" <rgrego...@yahoo.com> wrote in message
news:832ea96d.04011...@posting.google.com...
---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.560 / Virus Database: 352 - Release Date: 1/8/2004
Greg Crinklaw
> that Hoaxland has no understanding of aerosol scattering.
It doesn't matter what he understands or doesn't. Making up all these
stupid lies is the only way he can get the attention he craves. What he
really needs is to be introduced to a better understanding of brain
chemistry via a good psychiatrist.
--
Greg Crinklaw
Astronomical Software Developer
Cloudcroft, New Mexico, USA (33N, 106W, 2700m)
SkyTools Software for the Observer:
OhBrother
"N8IE" <dot...@dot.com> wrote in message
news:bq%Mb.165096$Dp5....@fe3.columbus.rr.com...
I can't believe the KoOk's are already queueing up to decry NASA and the
heat-shield on the spacecraft hasn't even cooled off yet.
More amazingly, as I look at the pictures released to the press, I see
poorly shot and only slightly contrast enhanced pictures, about what you'd
expect in the circumstances. However in some people's minds, every nit is
just evidence of a huge conspiracy. This time it's to cover up the
"obvious" life on Mars.
I remember how the discussions raged on about the Cydonia face, and let's
not forget about the crystal citys on the moon! Huge conspiracy. NASA
KNOWS there are alien cities there! Several years later another probe goes
back and shoots the same spot, Oops! just a big crater. Does KoOkdom say
"well, guess we got that one wrong"? Nope! Off they go pixelating the
pictures claiming there are Martian cities underground. Can't get enough
out of the regular pictures? Take the IR pictures, juggle the viewer
settings and Wah-Lah! More martian cities, hundreds of them! Oyez, and
along comes KoOk#2 to identify hangars, gardens, plaza's, factories, etc.
They never quit, and they can't understand why nobody pays any attention to
them.
<shutdown RANT mode>
O'
David Knisely
> Did you actually LOOK at these images:
Yes, I did. Did you actually READ the sci.astro.amateur charter?
> Compare to this image which ALSO shows the Martian surface and sky:
>
> http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20040108a/color_panorama_sol6-A6R1_med.jpg
>
> The blue and green "calibration" tags are no longer blue and green,
> but rather red and brown.
It looks like there are problems with that image, as there are numerous color
"bloom" effects as well as odd color shifts. The sun angle was a little
lower, so this might have changed things somewhat. This image was obviously
put together in a hurry, so the probably didn't give the color balance the
attention it deserved (maybe you might want to send them a note about it, but
*please* be nice about it). However, you seem to imply that this was a
*deliberate* attempt to alter the colors for some as of yet unexplained
reason. You have provided little to back up this contention.
If you want to talk about the visual appearance of Mars through the telescope,
you would be welcome to do so (but it would be best to quit implying that NASA
is deliberately altering the appearance of their images for some as of yet
unstated hidden agenda). However, I would have to say that in about 35 years
of observing the heavens with instruments from 2.4 inches to 30 inches of
aperture, I have never really seen anything approaching true green with the
albedo markings on Mars. The darker albedo markings are not a lot darker than
the surrounding light regions, and are of very low color saturation. At best,
Syrtis Major is probably the only one which, at least to me has ever seemed to
show much of a really distinct color hue, and it is a more bluish-grey than
green. Other than this, most of the other dark areas appear of a neutral grey
or perhaps light brownish, and this is backed up to at least some extent by
many of the higher resolution color images taken by amateurs during the last
apparition. As for the visual "illusion" of "green" on Mars telescopically,
that has been demonstrated numerous times. Clear skies to you.
--
David W. Knisely KA0...@navix.net
Prairie Astronomy Club: http://www.prairieastronomyclub.org
Hyde Memorial Observatory: http://www.hydeobservatory.info/
**********************************************
Jmpngtiger
jt
james
wrote:
>Robert Clark wrote:
>
>> "There is no scientific reason, why JPL is colorizing
>> Mars in that dull red tint as in their press release images.
>
>If you don't like the color that the web page shows, go get the images and use
>one of the image processing programs and tweak the color yourself. Otherwise,
>there is no scientific reason why Robert Clark posted this to
>sci.astro.amateur, as it is off-topic there (go read the charter).
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Since this thread is being crossposted to several groups maybe it
would be wise to post the address of a charter that evenI do not know
about.
james
Carl R. Osterwald
<capel...@yahoo.com> wrote:
> > All it shows is
> > that Hoaxland has no understanding of aerosol scattering.
>
> It doesn't matter what he understands or doesn't. Making up all these
> stupid lies is the only way he can get the attention he craves. What he
> really needs is to be introduced to a better understanding of brain
> chemistry via a good psychiatrist.
I agree, for him the spotlight is like crack cocaine.
-=-=-=-=-
David Knisely
> Since this thread is being crossposted to several groups maybe it
> would be wise to post the address of a charter that evenI do not know
> about.
ftp://ftp.uu.net/usenet/news.announce.newgroups/sci/sci.astro.amateur
The charter and history of the USENET newsgroups are available with only a
short search with any halfway decent search engine. Some do not have
charters, but others do. Clear skies to you.
Trane Francks
> Did you actually LOOK at these images:
Yes.
> The blue and green "calibration" tags are no longer blue and green,
> but rather red and brown.
Which says what, Bob? Fffff.... Ffffff..... Filters!
Since NASA is being kind enough to include the calibration
platform in the images, feel free to adjust and tweak things to
your heart's content.
trane
--
//------------------------------------------------------------
// Trane Francks tr...@gol.com Tokyo, Japan
// Practice random kindness and senseless acts of beauty.
lord freepness
"Chris L Peterson" <c...@alumni.caltech.edu> wrote in message
news:npu800pen5rsak8dc...@4ax.com...
> That's a crock! If so, B&W photos would be inadmissible. Photos taken
with
> daylight film under fluorescent lights would be inadmissible. Photos
taken under
> unusual lighting conditions would be inadmissible.
> _________________________________________________
>
> Chris L Peterson
> Cloudbait Observatory
> http://www.cloudbait.com
I was speaking/refering to of photos which were developed using
light filters and imagers which would deliberatly alter color or contrast
hue, as in the case of B&W. (in other words negatives which were
deliberatly run thru a filter onto the photo paper with intent to
alter details. hope this is clear now)
Chris L Peterson
<boing...@amishonline.com> wrote:
>I was speaking/refering to of photos which were developed using
>light filters and imagers which would deliberatly alter color or contrast
>hue, as in the case of B&W. (in other words negatives which were
>deliberatly run thru a filter onto the photo paper with intent to
>alter details. hope this is clear now)
Well, I'm sure that digitally enhanced photos (including color enhancements) are
entered into evidence all the time. If that was a standard once, it certainly
isn't anymore- and a good thing, too, since it would be a patently absurd rule
of evidence.
Paul Neave
> Mars color question.
Fast-forward a bit and the color question is explained here:
W K
"S.D.C." <every...@yahoodeletethis.ca> wrote in message
news:tjq80099ol03td3u8...@4ax.com...
> Thank you Greg,
>
> You saved me the trouble of responding to this ridicules thread!
>
> If I didn't have conspiracy crackpots, I'd have little to laugh at.
and thats the real conspiracy.
Of course, you'd just laugh it off as a silly theory, but THATS WHAT THE
GOVERNMENT WANT.
Greg Crinklaw
So are you one of the gullible people who believe everything any crakpot
says or are you joking?
Chris L Peterson
>So are you one of the gullible people who believe everything any crakpot
>says or are you joking?
What's funny to me is that these people actually think that the government is in
a position to hide things. They don't seem to realize that aside from funding,
the government has very little to do with the space program. The vehicles and
instruments are privately designed and built, or built by agencies like JPL that
aren't really all that governmental. They are operated mostly by scientists who
are either privately affiliated or connected with some educational institution.
That's an awful lot of non-government employees who still have to be kept in
line somehow...
All these people hiding monumental secrets, and this in a system that can't even
keep it quiet when somebody in a high place pokes his pecker in the wrong place.
Quaoar
Alan the Horse
wrote:
>Send men. Then we'll know for sure.
Sure. No chance they'll be in on the coverup, nosiree. Governments,
corporations, agencies, universities, amateur astronomers and radio
operators, millions in on it. But fly two Air Force or Navy guys out
there, and then we'll have the TRUTH. Yep, that'll do 'er fer sher.
(hoping intended sarcasm is noted)
Jmpngtiger
jt
Dave Oatley
area 51 and now you complain about the colour :-)lol
"Quaoar" <qua...@tenthplanet.net> wrote in message
news:-7edna5MZP3...@comcast.com...
Robert Clark
target in the NASA released color images is that in the images showing
the Martian surface they used a near-infrared filter instead of the
usual red filter.
This is from a conversation on slashdot.com:
=======================================
Re:If ya don't like their colors, then do it yours (Score:1)
by tommy_teardrop (228273) on Saturday January 10, @09:44AM (#7937278)
I've done a bit of experimenting with these files, comparing the
colour wheel to the images taken on Earth, and in order to get a
reasonable approximation of the 'true colours', you need the L4, L5,
and L6 filters, for red, green and blue respectively. Ironically, the
main problem is that there aren't yet pictures using the red filter. A
lot of the images triplicated with the blue green and infrared images.
(L6, 480; L5 530; L2 750)
The use of the L2 infrared filter means that the blue colours are
oversampled (at least on the colour chart). Once the L4 filter images
are used on the planet, full colour images will be ours.
-- IANAL, BIPOOTV
=======================================
Re:If ya don't like their colors, then do it yours (Score:1)
by rgclark (314480) on Tuesday January 13, @12:59PM (#7964175)
"I've done a bit of experimenting with these files, comparing the
colour wheel to the images taken on Earth, and in order to get a
reasonable approximation of the 'true colours', you need the L4, L5,
and L6 filters, for red, green and blue respectively. Ironically, the
main problem is that there aren't yet pictures using the red filter. A
lot of the images triplicated with the blue green and infrared images.
(L6, 480; L5 530; L2 750)
The use of the L2 infrared filter means that the blue colours are
oversampled (at least on the colour chart). Once the L4 filter images
are used on the planet, full colour images will be ours.
-- IANAL, BIPOOTV"
This still doesn't explain why the image of the sundial has the colors
looking perfectly fine including the green and blue.
It's only the images that also show the surface or sky that wind up
with the wrong colors for the calibration targets on the sundial.
Are you saying this image of the sundial was taken without using the
red filter:
http://marsrovers.jpl.nasa.gov/gallery/press/spiri
t/20040108a/PIA05018_br.jpg
Bob Clark
=======================================
Re:If ya don't like their colors, then do it yours (Score:1)
by tommy_teardrop (228273) on Wednesday January 14, @07:33AM
(#7972065)
No - these calibration images are taken with the L4, L5, L6 filters.
There are images of the color wheel in all the filters (L1-7, R1-7),
but very limited ones of the surface/sky in anything but L2, L5 and
L6. In fact, there are now L4 images available. The true colour sky
looks white, but does seem to have a greenish tinge to it.
You can try this yourself if you have an imaging program that lets you
use RGB colour channels. If you put color wheel images using L2 in
red, L5 in green and L6 in blue, and move back to full colour, it
looks nothing like the images you linked to. Blue looks bright
pink-purple. If you use L4, L5, and L6, the colours come out just like
that image you showed. Most of the posted colour images are colourised
using the three main imaging filters (L2, L5, and L6), because those
are the mainly used ones. It makes sense, the image quality is better,
but one down side is that it doesn't give you as close a real colour
as the L4 filter does.
I urge you to try it, as it's great fun... but then I'm a dork.
-- IANAL, BIPOOTV
=======================================
I can understand that with scientific observations the near-infrared
might be very useful, but it seems to me for an image to be released
to the news media for public relations the red filter would be used to
give the most accurate color rendition of the surface.
I've also read that it's impossible to get a true color rendition even
by altering the color ratios when this near-infrared filter is used.
In the last post copied above, the fellow suggests there are now some
images that use the correct L4 filter for the RGB color combination.
Perhaps he is referring to images like the one visible here during
this Spirit press conference:
http://apnews.myway.com/image/20040110/MARS_ROVER.sff_RS103_20040110150347.html
You'll notice the sky is a very pale blue. Actually if you look at the
mirrored sky in the calibration target image, you'll see that when the
Sun is high in the sky the sky color is light grey to pale blue,
similar to the way it looks in this image. This to me is itself a very
interesting scientific fact, the sky looks light grey to pale blue
when the Sun is high in the sky.
It is only when the Sun is low in the sky does the mirrored sky look
pale orange in the calibration image. This is quite analogous to what
we see on Earth during sunsets.
In short, I think it was a poor decision to use the near-infrared
filter instead of the correct visual light filter in composing the
color images to be released to the press to give an idea of the actual
colors on the Martian surface.
(As I write this it occurs to me how strange that sounds, "You use an
infrared filter instead of a visual light filter to give a VISUAL
light image of the scene?")
Bob Clark
rgrego...@yahoo.com (Robert Clark) wrote in message news:<832ea96d.04011...@posting.google.com>...
Martin Lewicki
Colour in the environment depends on the colour of ambient light. In a
golden sunset reds (like red cars, shirts etc) look bright - even
iridescent, while blues are very subdued. On Mars the ambient colour is s
rusty hue so colour on the colour dial will necessarily be skewed for the
same reason! That's why clothe shops must use "daylight" fluoros rather
than tungsten (amber tinted) lights. Otherwise customers may be in for a
surprise when outdoors. Indeed the first Viking images were adjusted to
make the Martian sky a "natural blue" - until they had a look at the colour
dial and were shocked to find they way off in their estimate. The colours
were readjusted to the more realistic tints that we all now know.
Martin Lewicki
Robert Clark
> target in the NASA released color images is that in the images showing
> the Martian surface they used a near-infrared filter instead of the
> usual red filter.
>
That the sky is blue when the Sun is high in the sky and orange when
low in the sky analogous to the situation on Earth is an important
scientific fact.
For instance on a web broadcast with JPL scientist Dr. Eric Wegryn it
was suggested that modeling suggested the daytime sky should always be
orange or tan, and that this was confirmed by Spirit images. But of
course the color images released then used the wrong filter for
creating a visual color image thereby incorrectly giving the sky a
reddish cast.
A later image using the correct visual light color filters showed the
sky with a pale blue color:
http://apnews.myway.com/image/20040110/MARS_ROVER.sff_RS103_20040110150347.html
This suggests there is something wrong with the modeling of the color
of the Martian sky.
Several webcasts on the MER missions can be found here:
Exploratorium: Journey to Mars.
http://www.exploratorium.edu/mars/webcasts.html
The webcast discussing the color of the Martian sky is here:
Tuesday, January 6, 2 p.m.
View from Mars
With Exploratorium Physicist Dr. Paul Doherty
Find out what sunsets look like on Mars and what makes the red planet
red with images taken by MERs' cameras.
http://www.exploratorium.edu/mars/mars-040106.ram
Bob Clark
--------------------------------------------------------------
For email response, send to same userid as above, but append
Hotmail.com instead of Yahoo.com.
--------------------------------------------------------------
David Knisely
> A later image using the correct visual light color filters showed the
> sky with a pale blue color:
>
> http://apnews.myway.com/image/20040110/MARS_ROVER.sff_RS103_20040110150347.html
>
> This suggests there is something wrong with the modeling of the color
> of the Martian sky.
I was watching those news conferences and that image did *not* have a blue
sky like the one shown on this web page! It may be because of the video
projector used and the cameras which took that image in the auditorium, or
that image may have been altered by those who put it up on the web site. The
Martian sky is not that blue!
Thad Floryan
> Robert Clark wrote:
>
> > A later image using the correct visual light color filters showed the
> > sky with a pale blue color:
> >
> > http://apnews.myway.com/image/20040110/MARS_ROVER.sff_RS103_20040110150347.html
> >
> > This suggests there is something wrong with the modeling of the color
> > of the Martian sky.
>
> I was watching those news conferences and that image did *not* have a blue
> sky like the one shown on this web page! It may be because of the video
> projector used and the cameras which took that image in the auditorium, or
> that image may have been altered by those who put it up on the web site. The
> Martian sky is not that blue!
That is true. And to understand why, one must first consider the composition
of Earth's atmosphere and how Mars' differs, then visit:
Robert Clark
"On another issue, mission members said the Red Planet, as seen in
gorgeous panoramic shots from the rover, may not be really red.
The photos of bright red dust, rusty rocks and salmon sky were
color-balanced to approximate what a person might see standing on the
martian surface, but it may be weeks before scientists perform the
calculations to show true color, said Ray Arvidson of Washington
University, a scientist on the project.
Mars was sort of a medium chocolate brown in photos taken by the
Viking landers in 1976, he said."
http://abcnews.go.com/wire/US/ap20040122_135.html
Really, I don't think it's that hard. Just use the same color
combination you used to get the image of the sundial that showed the
color tags with the correct colors.
Do the same thing except have both the calibration sundial and the
Martian sky and surface in the picture at the same time.
Bob Clark
Greg Crinklaw
> Thunderstorm Delays Rover's Work on Mars.
> "On another issue, mission members said the Red Planet, as seen in
> gorgeous panoramic shots from the rover, may not be really red.
> The photos of bright red dust, rusty rocks and salmon sky were
> color-balanced to approximate what a person might see standing on the
> martian surface, but it may be weeks before scientists perform the
> calculations to show true color, said Ray Arvidson of Washington
> University, a scientist on the project.
> Mars was sort of a medium chocolate brown in photos taken by the
> Viking landers in 1976, he said."
> http://abcnews.go.com/wire/US/ap20040122_135.html
>
> Really, I don't think it's that hard. Just use the same color
> combination you used to get the image of the sundial that showed the
> color tags with the correct colors.
> Do the same thing except have both the calibration sundial and the
> Martian sky and surface in the picture at the same time.
When you use the IR filter for your red it isn't that simple. It's not
possible to make a simple combination of the three colors that yield
"correct" colors over the entire visible spectrum: you can make the dirt
and sky about right or you can make the blues and greens about right,
but you can't do both.
Clear skies,
Greg
Volker Hetzer
"Robert Clark" <rgrego...@yahoo.com> schrieb im Newsbeitrag news:832ea96d.04012...@posting.google.com...
> Thunderstorm Delays Rover's Work on Mars.
> "On another issue, mission members said the Red Planet, as seen in
> gorgeous panoramic shots from the rover, may not be really red.
> The photos of bright red dust, rusty rocks and salmon sky were
> color-balanced to approximate what a person might see standing on the
> martian surface, but it may be weeks before scientists perform the
> calculations to show true color, said Ray Arvidson of Washington
> University, a scientist on the project.
> Mars was sort of a medium chocolate brown in photos taken by the
> Viking landers in 1976, he said."
> http://abcnews.go.com/wire/US/ap20040122_135.html
>
> Really, I don't think it's that hard. Just use the same color
> combination you used to get the image of the sundial that showed the
> color tags with the correct colors.
> Do the same thing except have both the calibration sundial and the
> Martian sky and surface in the picture at the same time.
not the colours I would be seeing with some sort of filtering.
Lots of Greetings!
Volker
Joe Knapp
"Greg Crinklaw" <capel...@yahoo.com> wrote in message
news:<100vpeo...@corp.supernews.com>...
> When you use the IR filter for your red it isn't that simple. It's not
> possible to make a simple combination of the three colors that yield
> "correct" colors over the entire visible spectrum: you can make the dirt
> and sky about right or you can make the blues and greens about right,
> but you can't do both.
If you look at an IR image (L2 filter) of the sundial, the blue mark on the
sundial looks brighter than anything. Why is that?
http://marsrovers.jpl.nasa.gov/gallery/all/2/p/002/2P126553017ESF0200P2100L2M1.JPG
In case the above link is munged:
http://tinyurl.com/yvsm6
The blue marker is at the lower right, red at the lower left. The blue
marker is much stronger in the IR it seems. No wonder there are no blues in
the color images?
For comparison, here are the green- and blue-filtered images:
http://marsrovers.jpl.nasa.gov/gallery/all/2/p/002/2P126553049ESF0200P2100L5M1.JPG
http://marsrovers.jpl.nasa.gov/gallery/all/2/p/002/2P126553081ESF0200P2100L6M1.JPG
The specs on the filters can be found in
http://athena.cornell.edu/pdf/tb_pancam.pdf, which specifies L2 as 750nm
with a bandpass of 20nm. L5 is 530(20) and L6 is 480(25).
Not so easy at all it seems.
Joe
Joe Knapp
has not generally been used so far, in favor of the L2 infrared filter.
However, there is on the Mars Rover website a series of images of the "east
hills" that includes an L3 shot
http://marsrovers.jpl.nasa.gov/gallery/all/2/p/008/2P127071833EFF0211P2262L3M1.JPG
http://marsrovers.jpl.nasa.gov/gallery/all/2/p/008/2P127072020EFF0211P2262L5M1.JPG
http://marsrovers.jpl.nasa.gov/gallery/all/2/p/008/2P127072176EFF0211P2262L6M1.JPG
Combining those three in Paint Shop Pro yields the following composite:
http://www.copperas.com/astro/mars_sky.jpg
Which shows a bluish sky and chocolate brown landscape. Interestingly, the
color of Mars from Pathfinder was determined to be a reddish chocalate
brown.
Combining L3, L5 and L6 images of the sundial yields the following:
http://www.copperas.com/astro/dial_rgb.jpg
Which shows that the color balance so obtained is pretty good, except the
blue is too purple. But it's certainly better than using the IR.
Joe
Greg Crinklaw
> Personally, I',m happy ythat they show the same colours I would be seeing,
> not the colours I would be seeing with some sort of filtering.
This is the root problem. Most people don't realize that color imaging
always involves a selection of filters. Maybe this can't be explained
in this medium, but I'll try with a simplified example.
First, you have to realize that your eyes are sensitive to light across
a broad range of colors. There range is approximated into three primary
colors: red, green and blue. Right there we have already strayed a bit
from "true" colors. Blue is at one end of the spectrum, red at the
other, with green in between. Your eyes are more sensitive to some
ranges of colors than others.
Now turn on a green pixel on your monitor. Is it "pure" green? It may
look like it, but it really glows in a range of colors centered on
green. Some color a little to the blue of green is there and some color
to the red of green is there too. Same thing for the red and blue
pixels. A lot of magic happens when you combine just the right amounts
of red, green, and blue to trick your eye into thinking you see orange
or fuchsia. I won't even get into color inks...
Anyhow, the trick its to take an image using three filters, each of
which records light in the same way that your monitor displays it: most
sensitive at the same shade of green, and less sensitive to the red or
blue of the primary color. And the way the sensitivity drops off to
either "side" of the primary color must match the way the green pixel
glows.
Now, try using an IR filter instead of a red filter. I don't know the
exact specs of the filters they are using, but imagine for a moment that
not only is the IR filter sensitive to a different range of colors
(colors your eye normally can't see well or at all) but imagine that it
is also sensitive to a much broader range of colors. In other words, it
is too sensitive to the colors to each "side" of the color of interest.
When you make your red pixel glow with the value recorded using this
filter it will glow in the narrow range of reds it was designed to glow
in. But this does not match the wider range that was recorded... The
result is that when you combine it with the green and blue it combines
with a different relative intensity with the green than it does with the
blue that it would otherwise. Thus, you can't exactly reproduce the
color balance over the whole spectrum.
My apologies if that didn't make any sense. I hope that the reader at
least understands that there is no such thing as simple color imaging;
that's just an illusion we all live with because the magic of color
imaging goes on behind the scenes and we are not usually aware of it.
Finally, I'll remind everyone that this is a scientific mission. The
imaging is selected for science purposes, not to make pretty pictures
for you to look at.
ANDREW ROBERT BREEN
Greg Crinklaw <capel...@yahoo.com> wrote:
>Robert Clark wrote:
>> Thunderstorm Delays Rover's Work on Mars.
Unfortunately some none-so-good-news. Spirit is reported as having
ceased sending intelligable data and not responding to commands.
http://news.bbc.co.uk/1/hi/sci/tech/3421071.stm
Not good.
--
Andy Breen ~ Interplanetary Scintillation Research Group
http://users.aber.ac.uk/azb/
Feng Shui: an ancient oriental art for extracting
money from the gullible (Martin Sinclair)
Robert Clark
> > Thunderstorm Delays Rover's Work on Mars.
> > "On another issue, mission members said the Red Planet, as seen in
> > gorgeous panoramic shots from the rover, may not be really red.
> > The photos of bright red dust, rusty rocks and salmon sky were
> > color-balanced to approximate what a person might see standing on the
> > martian surface, but it may be weeks before scientists perform the
> > calculations to show true color, said Ray Arvidson of Washington
> > University, a scientist on the project.
> > Mars was sort of a medium chocolate brown in photos taken by the
> > Viking landers in 1976, he said."
> > http://abcnews.go.com/wire/US/ap20040122_135.html
> >
> > Really, I don't think it's that hard. Just use the same color
> > combination you used to get the image of the sundial that showed the
> > color tags with the correct colors.
> > Do the same thing except have both the calibration sundial and the
> > Martian sky and surface in the picture at the same time.
>
> When you use the IR filter for your red it isn't that simple. It's not
> possible to make a simple combination of the three colors that yield
> "correct" colors over the entire visible spectrum: you can make the dirt
> and sky about right or you can make the blues and greens about right,
> but you can't do both.
>
> Clear skies,
> Greg
>
A pretty detailed examination of the issue is presented here:
SCI/TECH: NASA Is Not Altering Mars Colors.
http://www.abovetopsecret.com/forum/viewthread.php?tid=30048
I understand that the reason the colors are changed in the
calibrations tags is because in the Red, Green, Blue composed color
image, they used a near-infrared filter in place of the Red one.
What I'm saying is that if they used the correct Red, Green, Blue
filters to produce the color image of the calibration sundial and it
showed the colors on the sundial looked the same in the Martian light
as they do on Earth, why suddenly use a near-infrared filter to
produce a VISUAL light image?
Especially when this winds up distorting the colors?
At this date NASA still has not released a color image showing the
Martian sky and surface using the correct Red, Green, Blue filters
that *also* shows the reference color chart so we can be confident of
the color combination.
They either show the reference color sundial and the Martian sky but
use the near-infrared filter thereby distorting the color, or they use
the correct RGB filters but only show the reference sundial not any
part of Mars, or they use the correct RGB but only show Martian
surface/sky not the reference chart so we're not sure of the color
combinations.
Mars Opportunity arrives on Mars tomorrow. I hope this time the first
publicly released panoramic image uses the visual light RGB filters to
compose the image (AND shows that little calibration sundial somewhere
in the image.)
Robert Clark
>
> > A later image using the correct visual light color filters showed the
> > sky with a pale blue color:
> >
> > http://apnews.myway.com/image/20040110/MARS_ROVER.sff_RS103_20040110150347.html
> >
> > This suggests there is something wrong with the modeling of the color
> > of the Martian sky.
>
> I was watching those news conferences and that image did *not* have a blue
> sky like the one shown on this web page! It may be because of the video
> projector used and the cameras which took that image in the auditorium, or
> that image may have been altered by those who put it up on the web site. The
> Martian sky is not that blue!
> --
> David W. Knisely KA0...@navix.net
I tried to find that image on the Mars Rover web site and couldn't
find it. If anyone knows which one it is I'd be glad to see it.
A detailed explanation of the issue is presented here:
SCI/TECH: NASA Is Not Altering Mars Colors.
http://www.abovetopsecret.com/forum/viewthread.php?tid=30048
The author presents the view that the released color images are
relatively accurate representations of the Martian sky and surface.
However, his analysis doesn't justify how the colors can be considered
accurate when the green and blue color tags on the calibration device
appear brown and red in the released color images that show Martian
sky and surface.
Here is an image I produced by combining Red, Green, Blue filter
images into a single color image. It contains some bluish areas in the
image (the purple square at the top is due to one of the filter images
missing that square):
http://sciforums.com/attachment.php?attachmentid=2465
And here is the image of the same area released by NASA. It does not
contain the bluish areas:
http://sciforums.com/attachment.php?attachmentid=2466
There is a JPL logo on the rover that is visible in the image. This
might be able to be used to determine which of these images is more
accurate by comparing to the color of this logo as appears in images
of the rover taken on Earth.
Bob Clark
Greg Crinklaw
> Mars Opportunity arrives on Mars tomorrow. I hope this time the first
> publicly released panoramic image uses the visual light RGB filters to
> compose the image (AND shows that little calibration sundial somewhere
> in the image.)
Why? I'm sure they have a good reason to use the near IR. Believe it
or not they didn't send these things to mars just to make pretty pictures.
Greg Crinklaw
> The author presents the view that the released color images are
> relatively accurate representations of the Martian sky and surface.
They are. Why is it so difficult to accept that we know what the color
of the Martian surface is? Mars wasn't discovered yesterday you know.
There has been careful analysis done on Viking and Pathfinder results.
No, the colors from Spirit aren't perfect, and no, the images released
so far don't accurately reproduce the "true" colors over the entire
spectrum. The "true" color of the soil and rocks is a sort of copper
brown. See the final Pathfinder results for an example. As I said
before this is much ado about nothing.
Volker Hetzer
"Greg Crinklaw" <capel...@yahoo.com> schrieb im Newsbeitrag news:100vu7m...@corp.supernews.com...
> Volker Hetzer wrote:
> > Personally, I',m happy ythat they show the same colours I would be seeing,
> > not the colours I would be seeing with some sort of filtering.
>
> This is the root problem. Most people don't realize that color imaging
> always involves a selection of filters. Maybe this can't be explained
> in this medium, but I'll try with a simplified example.
Ok, so this is the best approximation they can do given the fact that
they didn't record the colours that would be needed for a picture
showing mars as I would see it.
Lots of Greetings and Thanks!
Volker
Robert Clark
some colors altered from the correct values.
Not intentionally. The correct color calibration calculations haven't
been done yet. It notes the NASA logo color is altered from blue to
red.
Rover's stunning image of lander
Empty nest: The Columbia Memorial Station at Gusev Crater
http://news.bbc.co.uk/2/hi/science/nature/3418147.stm
A high resolution image is here:
Press Release Images
21-Jan-2004
Empty Nest
http://origin.mars5.jpl.nasa.gov/gallery/press/spirit/20040121a.html
In relation to which of the following two images is more accurate:
Image composed by just straight combining L4, L5, L6 filters.
http://sciforums.com/attachment.php?attachmentid=2465
and
Image released by NASA probably with some normalization applied to the
filters. http://sciforums.com/attachment.php?attachmentid=2466
note that the JPL logo next to the NASA logo in the "Empty nest" image
has the same red color as the NASA logo, which suggests it started out
with the same blue color as the NASA logo.
Then in the comparison of the two images above note that the straight
combined image of L4, L5, L6 has a blue JPL logo, while the NASA
released image has a red JPL logo.
Bob Clark
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For email response, send to same userid as above, but append
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rgrego...@yahoo.com (Robert Clark) wrote in message news:<832ea96d.04012...@posting.google.com>...
Dosco Jones
http://www.atsnn.com/story/30048.html
"Robert Clark" <rgrego...@yahoo.com> wrote in message
news:832ea96d.04012...@posting.google.com...
Robert Clark
in the Spirit image that would mean the NASA released image is
probably more accurate than the one that shows the bluish areas on the
rocks.
Bob Clark
Paul Neave
image, so the colors will be off - but color correcting software
has tried to bring it back to a 'true' color.
bart janssens
But there is more,
the whole space-program is fake
wolfhedd
PLEASE!!!!!!!!!!!!!!!!!!!!!! geese!
wolfhedd
"OhBrother" <Nob...@noplace.com> wrote in message
news:0I%Mb.40229$RT.2...@fe2.columbus.rr.com...
>
> "N8IE" <dot...@dot.com> wrote in message
> news:bq%Mb.165096$Dp5....@fe3.columbus.rr.com...
> > I bet it's that damn Ted Turner again. He just has to colorize
everything.
> >
> > "Robert Clark" <rgrego...@yahoo.com> wrote in message
> > news:832ea96d.04011...@posting.google.com...
> <Initiate RANT mode>
>
> I can't believe the KoOk's are already queueing up to decry NASA and the
> heat-shield on the spacecraft hasn't even cooled off yet.
>
> More amazingly, as I look at the pictures released to the press, I see
> poorly shot and only slightly contrast enhanced pictures, about what you'd
> expect in the circumstances. However in some people's minds, every nit is
> just evidence of a huge conspiracy. This time it's to cover up the
> "obvious" life on Mars.
>
> I remember how the discussions raged on about the Cydonia face, and let's
> not forget about the crystal citys on the moon! Huge conspiracy. NASA
> KNOWS there are alien cities there! Several years later another probe
goes
> back and shoots the same spot, Oops! just a big crater. Does KoOkdom say
> "well, guess we got that one wrong"? Nope! Off they go pixelating the
> pictures claiming there are Martian cities underground. Can't get enough
> out of the regular pictures? Take the IR pictures, juggle the viewer
> settings and Wah-Lah! More martian cities, hundreds of them! Oyez, and
> along comes KoOk#2 to identify hangars, gardens, plaza's, factories, etc.
>
> They never quit, and they can't understand why nobody pays any attention
to
> them.
>
> <shutdown RANT mode>
>
> O'
>
>
>