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Viking 1 Lander, 31st July 1977
djellison
post May 14 2005, 09:04 PM
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Just perusing thru the Viking Lander dataseta ( amazing, less than 1CD each - and I've got 9 DVD's for Spirits Pancam Sols 1-270 alone ohmy.gif ) and found this three-colour set - I thought it looked fab, and I've never seen it before.

Here's the info...
QUOTE
Product Id  11E123-GRN
Spacecraft Name  VIKING_LANDER_1  Instrument Name  CAMERA_1
Mission Phase Name  EXTENDED MISSION  Target Name  MARS
Start Time  1977-07-31T08:08:51Z  Stop Time  1977-07-31T08:16:12Z
Planet Day Number  366  Local Time  10.70
Start Azimuth  162.50 degrees  Stop Azimuth  245.00 degrees
Center Elevation  10.00 degrees  Sampling Parameter Interval  0.12 degrees
Observation Type  COLOR TRIPLET  Filter Name  GREEN
Gain Number  4  Offset Number  1
Detector Temperature  -18.10  Dust Flag  FALSE
Start Rescan Number  0  Total Rescan Number  0
Scan Rate  16000 BPS  Data Path Type  RECORDED UHF LINK
Line Samples  689  Missing Samples  3
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GregM
post May 23 2005, 02:48 AM
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.
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4th rock from th...
post May 23 2005, 09:48 PM
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Very good!
I think the Viking missions deserve a on-line gallery like the current MER rovers have at http://www.lyle.org/%7Emarkoff/.
Given the small amount of data it might even be simpler to do!


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tedstryk
post May 24 2005, 02:13 PM
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QUOTE (4th rock from the sun @ May 23 2005, 09:48 PM)
Very good!
I think the Viking missions deserve a on-line gallery like the current MER rovers have at http://www.lyle.org/%7Emarkoff/.
Given the small amount of data it might even be simpler to do!
*



It would be nice to make a site utilizing all planetary landers (on Venus, Mars, the moon, and Titan). Perhaps this is a project that could be undertaken after the MER mission (since if MSL gets delayed, which looks certain without a political rescue and barring some scout lander coming from nowhere, the post-MER period might provide a nice chance to dig back in the archives - I know there will be the Phoenix interlude, but I suspect it will be shortlived due to the highl latitude coupled with solar power).

Ted


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djellison
post May 24 2005, 02:18 PM
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Well - I'll certainly go thru and start making all the RGB combos I can find for V1 and V2 - but the only problem I have is the same problem I have with Pathfinder .img's

They're not exactly RAD's are they ohmy.gif Some will come out looking about right but many are obviously not properly calibrated as one would find with an MER RAD with img2png -r

I think this might be an investigation for super-bjorn smile.gif

If you wish to grab a burnable-to-CD .img of each Viking archive..

http://pdsimg.jpl.nasa.gov/data/vl1_vl2-m-lcs-2-edr-v1.0/

The folders of the same names are simply the full content of the .img (which is a sort of .iso)

Looking here - http://pdsimg.jpl.nasa.gov/data/vl1_vl2-m-.../vl_0001/calib/

and especially here
http://pdsimg.jpl.nasa.gov/data/vl1_vl2-m-...lib/calinfo.htm

I'm sure the information to generate radiometrically calibrated data is there - I think Bjorn may just need to re-do a bit of IMG2PNG to do it. If he can do that - I'll happily generate every RGB set I can find.

I think MPF's IMP needs the same attention in Img2Png'ing


Doug
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tedstryk
post May 24 2005, 03:08 PM
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QUOTE (djellison @ May 24 2005, 02:18 PM)
Well - I'll certainly go thru and start making all the RGB combos I can find for V1 and V2  - but the only problem I have is the same problem I have with Pathfinder .img's

They're not exactly RAD's are they ohmy.gif  Some will come out looking about right but many are obviously not properly calibrated as one would find with an MER RAD with img2png -r

I think this might be an investigation for super-bjorn smile.gif

If you wish to grab a burnable-to-CD .img of each Viking archive..

http://pdsimg.jpl.nasa.gov/data/vl1_vl2-m-lcs-2-edr-v1.0/

The folders of the same names are simply the full content of the .img (which is a sort of .iso)

Looking here - http://pdsimg.jpl.nasa.gov/data/vl1_vl2-m-.../vl_0001/calib/

and especially here
http://pdsimg.jpl.nasa.gov/data/vl1_vl2-m-...lib/calinfo.htm

I'm sure the information to generate radiometrically calibrated data is there - I think Bjorn may just need to re-do a bit of IMG2PNG to do it.  If he can do that - I'll happily generate every RGB set I can find.

I think MPF's IMP needs the same attention in Img2Png'ing


Doug
*



I have also had trouble in that the slow scanning of the Viking cameras can lead to subtle differences between frames.


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Chmee
post May 24 2005, 03:37 PM
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So does this picture symbolize something? Like giving the middle-finger to the Soviets: "Hey we landed (successfully) here first, so there!"

biggrin.gif
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djellison
post May 24 2005, 03:54 PM
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QUOTE (tedstryk @ May 24 2005, 03:08 PM)
I have also had trouble in that the slow scanning of the Viking cameras can lead to subtle differences between frames.
*


iirc - R, G and B were actually scanned at the same time, together. This is how I read the operation of the cameras anyway. The scanning of three channels at the same time ( R,G,B or IR1,IR2,IR3 ) would generate data at the same rate as the high resolution sensors in monochrome ( i.e. 3 channels of .12 degrees = 1 channel of .04 degrees )

i.e.

http://pdsimg.jpl.nasa.gov/data/vl1_vl2-m-...xx/12a006bu.htm

http://pdsimg.jpl.nasa.gov/data/vl1_vl2-m-...xx/12a006gn.htm

http://pdsimg.jpl.nasa.gov/data/vl1_vl2-m-...xx/12a006rd.htm

are all part of the same sequence and all started and finished at the same times.

Doug
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Phil Stooke
post May 24 2005, 04:41 PM
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Chmee: "So does this picture symbolize something? Like giving the middle-finger to the Soviets: "Hey we landed (successfully) here first, so there!" "

No, it doesn't!

But seriously... a nice image. Lots of these Viking images are rarely seen and certainly deserve a wider audience. A composite of this color merged with the high res frame of the area would be very impressive too. I know Tim Parker has been doing some super-resolution stuff with these Viking images, too. There was an LPSC abstract a few years ago on it.

Phil


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tedstryk
post May 25 2005, 11:33 AM
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The frames I was working with when I had this problem were the few rare high resolution color images (which never turned out very well anyhow). It never occured to me that the lower resolution scans would be faster rolleyes.gif
QUOTE (djellison @ May 24 2005, 03:54 PM)
QUOTE (tedstryk @ May 24 2005, 03:08 PM)

I have also had trouble in that the slow scanning of the Viking cameras can lead to subtle differences between frames.
*


iirc - R, G and B were actually scanned at the same time, together. This is how I read the operation of the cameras anyway. The scanning of three channels at the same time ( R,G,B or IR1,IR2,IR3 ) would generate data at the same rate as the high resolution sensors in monochrome ( i.e. 3 channels of .12 degrees = 1 channel of .04 degrees )

i.e.

http://pdsimg.jpl.nasa.gov/data/vl1_vl2-m-...xx/12a006bu.htm

http://pdsimg.jpl.nasa.gov/data/vl1_vl2-m-...xx/12a006gn.htm

http://pdsimg.jpl.nasa.gov/data/vl1_vl2-m-...xx/12a006rd.htm

are all part of the same sequence and all started and finished at the same times.

Doug
*



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djellison
post May 25 2005, 11:50 AM
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I must admit - I did occasionally think "well, why not just to colour scans much slower?" when wondering about high res colour smile.gif

Doug
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edstrick
post May 25 2005, 11:56 AM
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The Viking Lander cameras had, as I recall, 12 Photo-diodes per camera. R,G,B,IR1,IR2, IR3 for multispectral imagery, 1 broadband diode for low-rez monochrome imaging, 1 un-amplified diode for direct sun imaging, and 4 hi-rez diodes at fixed focus steps to provide in-focus images at different ranges.

The diodes were mounted in two side-by-side lines, The RGB diodes were in one line, the IR diodes in the other. RGB and IR1-2-3 images are nearly perfectly registered (There is about 1 1/10 pixel error, which is enough to make nasty color fringing if you attempt to enhance IR color data), but there is mis-alignment in the forground between the 2 sets of diodes.

Imaging sequences were normally 1.) broadband low rez, 2.) Color low rez, 3.) broadband High-rez (using a selected high rez diode) and 4.) sun imaging. Color (and IR color) images were taken by scanning the same vertical scan line 3 times, then stepping the camera 1 field of view 0.12 deg over, and scanning the next line 3 times, using the 3 color or 3 infrared diodes in sequence. Low-rez diode images were 60 deg high centered at 5 or 10 deg elevation intervals (can't remember). High-rez diode images were 20 deg high. Image widths were variable, in increments of 64 (I think) scans. (64/3 for color)

The cameras also had a few "odd" imaging modes. They could take high-rez mode pics using color diodes, over-sampling the low-rez diodes with 0.04 deg sample spacing. HOWEVER, they could only take one color at a time, taking them in sequence, or at the same time of day on subsequent days. Usually, high-rez mode color images have annoying color fringes from sun movement from one image to the next in the sequence. The cameras also had a "motion detection" mode where the camera just continually image one vertical scan line up to a few hundred times or so. Didn't show much other than shadows moving, except for imaging sequences when Phobos's shadow passed over the landing site or nearby and they could see the sky <and foreground, if it was directly across the sun> darken by 10% or so and get the time of mid-eclipse EXACTLY.

The cameras returned (unfortunately) 6-bit data, which significantly degraded the IR color data, as there was very very low "color" contrast in IR images. For an imaging sequence, the camera's amplifier "Gain" (sensativity) could be set, as could an "offset" (zero-level) value. If gain was set too high, large parts of the images would be <and sometims were> saturated at a "Digital number" DN level of 63. Offset was generally set to near zero, so true black in the images is usually, THOUGH NOT ALWAYS, near zero in the EDR (experiment data record) data.

The simplest way to make quasi-true color images from Viking data is to select an image together with an image of a sunlit calibration test chart taken at a similar time of day at about the same time in the mission. The charts were tilted and didn't get really dusty (they did get some). Adjust gain in the RGB channels till the sunlit gray-steps on the chart are neutral shades of gray.

The red patch on the chart will look red, the green patch will look green, but the blue patch will look PURPLE. The Viking lander camera channels had a BIG gap between the response of the green and red channels where they overlap strongly in human vision (yellow and orange wavelengths), and the red channel had significant near IR response, where the blue paint chip had a strong increase in reflectivity in the near IR. Without quantitative remapping of the camera's output into channels matching the color response of the human eye, you cannot get true color data from the lander cameras.
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djellison
post May 25 2005, 12:11 PM
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The eclipse imagery I features in my talk on Saturday ( "It was a smash!" - The front bumper of Chris's Elise" )

http://www.unmannedspaceflight.com/doug_im.../v1_eclipse.jpg

The images used were....
http://pdsimg.jpl.nasa.gov/data/vl1_vl2-m-...xx/12f136bu.htm and the two following.

What I know about the Viking imaging system stems from about 4 hours of mad panic research last week smile.gif

I think I may have to learn how to do this 'programning' lark - I'm slowly becoming more and more of a 'confused artist' when trying to do some of the things I'd like to do smile.gif

Doug
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tedstryk
post May 25 2005, 04:22 PM
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Here is my latest attempt at a Viking 2 pan. For some reason, it is nearly impossible to get realistic-looking color saturation with Viking - the images either get to red or too green. One place looks right, and then another place gets out of wack. Ugghhh.



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tedstryk
post May 25 2005, 04:45 PM
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QUOTE (tedstryk @ May 25 2005, 04:22 PM)
Here is my latest attempt at a Viking 2 pan.  For some reason, it is nearly impossible to get realistic-looking color saturation with Viking - the images either get to red or too green.  One place looks right, and then another place gets out of wack. Ugghhh.


*


Edit: Actually, for images without saturated areas, I have found a solution. Enlarge the image, resample it, and shrink it back (it can be done without enlarging, but it degrades resolution further). Then overlay the color product over a mix of the three original images. Due to the resampling, the colors are not as harsh. Here is an example:



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