Hi,

I processed those images, based on the gain settings on the Viking cameras and the color filter wavelenghts.

The MER images here: http://www.lyle.org/~markoff/ provide a good idea of the general brightness and color tone of Mars. They are, as best as I know, the only proper calibrated Martian images, because they were based on a large number of filters, that cover all the visible spectrum (MER images generated by using the 6 filters with gamma correction).

The important thing is that, after applying my processing protocol, all Viking images look consistent with the MER and Pathfinder results. Even sunsets and sunrises.

One thing that I couldn't correct was the camera gradient in the upper part if the image. So the sky still looks as if it darkens a lot above the horizon...

I believe there is some kind of obstruction that causes the darkening. Another problem with Viking color, which I am sure you have encountered, is that since the images were 8-bit selectively cut down to 6-bit for transmission, there are a lot of washed-out skies.

Yes, very nice processing and an interesting set of data. When I was playing with the Viking data, I think that there were few panoramas that showed the distribution of the frost around the site. One interesting thing would be to create some vertical projections of those and chart the evolution of the frost patches. I don't know if that was done at the time, but I think it would be an interesting project, provided that there are enough images.

Yes... that's apparent when I corrected the images for gain. See this one for example: http://www.astrosurf.com/nunes/explor/explor_vik.htm

I didn't try to change the original look of the data much, but in some cases I Just filled the sky with a uniform "general Mars Sky color".

That is what I was referring to...I have done the same. But my work has always been focused more on super-resolution...which is why I was thrilled when you draped your color data over some of my black and white images.

http://www.astrosurf.com/nunes/explor/viking/21i093_cal.jpg
Sorry, I wanted to include a direct link to this image.

When I worked with that image, I didn't even try to mosaic it wit that very overexposed set. In this version, I did some color cloning near the left side of the image to get rid of color noise caused by "salt and pepper" in the raw data.

The Viking Lander cameras had a clear-glass dust-shield that vignetted the extreme top of the field of view (I think 40 deg above the horizon) The vignetting was different for each color channel (not filter.. the cameras used physically separate photodiodes for each color band. 3 vis, 3 infrared channels, 1 broadband, 1 high opacity sun channel, and 4 focus-steps for high resolution imaging. The vignetting proved somewhat useful as it let Viking image closer to the sun in the sky for atmosphere scattering properties that would have been otherwise possible.

During the extended mission, they jettisoned one or two of the dust shields but saw little effect: not much accumulated dust.

Thanks all for the answers..

Snow or no snow.. White Mars is as MAGICAL as is Earth in with a white (snow/ice) cover

First results from the new smart software...
This is animation from 10 NavCam frames from Sol956, published only today:

(I flattened a little the frames in order to make clouds more visible in the bright/dark areas).
Clouds seems to generate near the center.

Gorgeous!

Now, about that colourised version...


Bob Shaw

That is absolutely cool!

Now we need animation from a dust devil too. Capturing a landslide (as long as the rover is not involved) would be neat also--but would the images be made fast enough under that circumstance?. What is the time lapse for these images?

About 30 sec/per image. See http://www.lpl.arizona.edu/~lemmon/mer_dd.html.

Here is the colourised version of the clouds animation.

Taken on Sol 956.

jvandriel

Some details on the sol 956 sequence in this press image description. It turns out it wasn't captured using the new software.