Methods

Appendix 4 - Methods

Guidelines for visual search for life on Mars

To search candidates for past or current life in Mars rover images, the following guidelines can be given as a summary:

Look close. The scale of Martian life is small. Check images where rover cameras are directed downwards and close.
Look at shadow places and undersides of rock cliffs. Those are places where ultraviolet light of the Sun does not reach, and also the rock above partly provides protection from cosmic radiation.
Check distorted soil by rover wheels and sand piles resulting from drilling. The fresh underground soil can provide surprises.
All Curiosity MAHLI and ChemCam images, and Opportunity Microscopic Imager images, are good to check. They are directed to interesting targets.
Time series: If there is images taken of same area during several days, look for changes.
Colors: Check objects which color differs from overall background. After Gimp auto white balancing candidate fossils have had specific gray color. And current candidate extant life has had deep blue, green, white and yellow colors.
Check repeating patterns, textures and fractal type textures.
Symmetry: Living things often have symmetry planes, by which the two sides can be mirrored.

Finding one interesting looking object is a good beginning. But finding second or more similar objects allows classification and confirmation that the object class may really be something interesting.

Think about possible Earth analogs for discoveries: If life on Mars and Earth base to same DNA and evolution has followed same kind of tracks, then the discoveries may have similarities with past or current Earth life.

Image processing

Here I tell details how i process Curiosity and Opportunity images to get the natural colors. Dr. Lyall Winston Small, who is a real master in this area, told me how to do these.

Curiosity images

The Gimp image processing software is free: https://www.gimp.org/

The major improvement to Curiosity images comes from this:In Gimp "Color" tab select "Automatic" -> White balance. This very simple action returns natural colors. The same blue sky colors that NASA has used in some press release images. And this operation gives more details.

Note also in image above that in the MRO HiRISE image, targeted on Curiosity, the colors match the upper row.<

Opportunity and Spirit images

For Opportunity and Spirit images the free software "ImageJ" is excellent: http://imagej.net/

You can produce natural color images from the black and white archive images taken with blue, green and red filters. The file names of the originals have L2, L5, L7 or R2, R5, R7 included. 2 is red filter, 5 is green filter and 7 is blue. In imageJ: First Open one by one the 3 images. In "Image" tab select "Color" and then "Merge channels". Then opens a tab where you select the red, green and blue original files. Then "OK" and you get final color result. Then "File"-> save as jpeg. For the final fine tuning I use Microsoft office picture manager. And if there is some dark areas in image and only those should be made brighter, then Windows live photo gallery has very good tone balancing for it.

Some more mind bending images from Mars

In images below is some more interesting objects which i have not handled in main article. Sol 2, the Bunny case.

MOC 2012 image: interesting square, size 2x2 kilometers ( http://ida.wr.usgs.gov/fullres/divided/e10004/e1000462a.jpg ). About the square: It is nice to speculate how far life proceeded on Mars. Did it reach intelligence? This issue I have on purpose avoided in this article, but i handle it somehow in Appendix D: Fermi paradox.

Sol 305: Note the blue color of the stones and note how the soil close to these stones has same color. The Opportunity Sol 4382 microscopic imager image of revealed underground soil has several interesting objects.

Sol 1065: Fresh meteor impact? On Opportunity 2005-10-18 image there is similar. Spirit Sol 822 (image by Dr.L.W.Small): White fungi?

Sol 901 object has 2 similar objects, A - large one, and B - similar smaller one. Sol 640: Nice green surface and holes in a probable iron meteor.

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