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Posted by: Ant103 Sep 21 2009, 09:04 AM

Hi,

I want to show a special production I've made, a retake on the Sol 83 panorama showing the first frost at Vastitas Borealis Phoenix's landing site.

Create from PDS img files (conversion with the helpfull PDS Reader for ImageJ), colorisation in Gimp, stitching with Hugin, some adjustments in Gimp and creation of a synthetic sky from sky colors.
http://www.db-prods.net/blog/2009/09/18/vastitas-borealis-une-image-de-phoenix/

Hope you will like it .

Posted by: Zvezdichko Sep 21 2009, 10:13 AM

I liked it, thanks!

I think you should be very careful when you use the colorify function in GIMP. The image appears too reddish somehow, even unnatural (Look at the solar panels).

Keep up the good work!

Posted by: mps Sep 21 2009, 05:31 PM

I do know next to nothing about image processing, but I do know something about sunsets/rises (on Earth, of course) and that makes me thinking that maybe the solar panels ARE so reddish when the sun is so low in the sky.

Posted by: Paolo Sep 21 2009, 05:37 PM

Wow!! Looks like painted in some places!

Posted by: Stu Sep 21 2009, 05:50 PM

Personally I don't care if it's not 1000% accurate in terms of colour; that is a beautiful, beautiful image.

Posted by: ngunn Sep 21 2009, 07:45 PM

The problem with that is that whereas scattering in Earth's air subtracts blue light, giving red sunsets, on Mars the situation is reversed - Rayleigh scattering is negligible compared with the effect of the suspended dust. The dust filters out red light, giving blue sunsets. Check out that already famous sunset over Gusev image, or more recent ones.

http://www.nasa.gov/images/content/117988main_image_feature_347_ys_4.jpg

Posted by: Ant103 Sep 22 2009, 03:00 PM

Thanks for the comments . Especialy Stu

Zvezdichko : I am not using a colorification function in Gimp. It's made from 3 different filters (one neutral,-put in red mode- one green and one blue). The solar pannel look red because of dust accumulation on it accentuated by low sun (not a scattering but a dusty effect) and some frost. Anyway, the colors are not perfect. and after, it's not my target to have the true perfect exact colors (for me it's an affair of interpretation).

In the attachment you will find a highly reduced version created with a white pointing with the level tool (white pointing made on a place on the solar pannel). I find this version too greenish in some place.

Posted by: djellison Sep 22 2009, 03:14 PM

I'm seing differences in colour between pointings. Does the ImageJ PDS reader use the offset and scaling like img2png ?

Posted by: Ant103 Sep 23 2009, 07:27 AM

I don't know exactly. He read the IMG file in 16 bits format. But the PNG exportation is made in 8 bits. But there is various format of exportation like tiff, jpeg, fits, bmp, etc.
Tiff is the only one to be in 16 bits, but it's lead to have a very dark picture. I think there is some settings to make to have a brighter pic.