I was taking a look at some of the raw Mars 2020 images and downloaded a few of them. For some of the photos from the down-look camera, if you zoom into them, there's a stippling/grid pattern in the pixels over the entire image. What's the cause of this? It seems like all of the images that have this are in black and white, could it be something related to the different color channels?

section of the heat shield in a picture taken from the rover down-look camera


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See my recent answer for a somewhat in-depth discussion on how digital cameras see color. This is indeed an example of the characteristic stippling of a raw digital image that is taken by a camera that uses a Bayer filter ("method 2" in my answer) and is not yet "demosaiced", which is to say, full color information interpolated for each pixel based on the values of neighboring pixels. Almost every consumer digital camera that exists also utilizes a Bayer filter.

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    $\begingroup$ +1 Since "mars is red" and one out of four squares is much brighter than the other three and one out of four pixels in a Bayer filter (or similar) is red, do you think it's safe to assume that these are related? $\endgroup$
    – uhoh
    Feb 26, 2021 at 0:13
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    $\begingroup$ So, @emma , might be "fun" , if you can, to lay a grid over that pattern and then sum each 2x2 box to see if you get a "clean" greyscale image. Then assign RGBG to the 2x2 pixels and see if you get the intended color image! $\endgroup$ Feb 26, 2021 at 14:03

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