Mars.

Processed, leveled, cropped MCZ_LEFT, FL: 110mm
Sol: 880, RMC: 43.0000, LMST: 12:07:17
Original: https://mars.nasa.gov/mars2020-raw-images/pub/ods/surface/sol/00880/ids/edr/browse/zcam/ZL0_0880_0745060589_769EBY_N0430000ZCAM08882_1100LMJ01.png
Credit: #NASA/JPL-Caltech/ASU/65dBnoise

#Perseverance #Mars2020 #Solarocks #Space #crackedRocks

"There's more than one way to skin a cat"

The first image is part of an Arizona State University panorama composed from images captured on #Mars2020 Sol 4, "approximately simulating the colors of the scene that we would see if we were there viewing it ourselves."
https://mastcamz.asu.edu/galleries/mastcam-zs-first-high-resolution-mosaic-sol-4/?back=%2Fmars-images%2Fpanoramas-mosaics%2F%3Fitem_type%3D360-panoramas

The second image is the same but filtered for people with insensitivity to green.

When it comes to color perception or other sensory experience, things don't necessarily follow our preconceptions 😀

#GIMP

Mastcam-Z's First High-Resolution 360° Mosaic! (Sol 4) - Mastcam-Z

[Note: The banner image here is a lower-resolution MP4 movie file, and the JPEG available at the red button link below is a 1/3 resolution version. For full-resolution versions of this Mastcam-Z mosaic, click on the TIFF or PNG button below, and for additional versions of this panorama at full resolution, including 3-D anaglyphs for […]

Mastcam-Z

@65dBnoise

Colour perception varies more than most people realise.

I guess the folk that set up some of the M20 cameras and their image pipelines appreciate the raw images on the mission server more than others.

#cantpleaseeveryone

@PaulHammond51
Indeed, those people definitely know better. And knowing better makes them show a number of different approaches to viewing, rather than sticking to one for all intents and purposes.
@65dBnoise @PaulHammond51 I agree that color perception can vary quite a lot between different people, however there is a pretty well established process for digital cameras here on earth to produce natural looking colors.
NASA doesn't apply any of those established processes to the Mastcam images.
And what they are doing instead is no substitute to this process, from my understanding it's plainly wrong to call the "natural color images" true to what the human eye would see.

@stim3on @PaulHammond51
My concern here is visual perception of Martian terrain and how a viewer can make the most out of it. So I take a "high altitude" view on the subject, caring most for the end result.

Anyone who has ever dived deeper than 10m (or has seen pictures/movies) knows that everything at that depth looks blue-green, despite fish and corals still being colorful. If one needs to understand what goes on at the bottom of the sea, presenting one ...

1/4

scientists (and everyone else) use are made to improve perception of the object/process being observed. The objective is always to augment human perception with details hard to discern otherwise.

I believe that NASA follows the above as close as possible. When the task is to preserve color fidelity, they do that using calibration targets for each instrument, and other procedures pertinent to the task.

It's inconceivable to me that they don't make use of those facilities.

4/4

@65dBnoise I agree that showing Mars in this overly red depiction doesn't help for exactly the reasons you said.
Because our color perception will adjust to the reddish light on mars it would not even appear as red as shown in these images. Here is an example of a similarly red lighting situation I've see on earth. The left one is how yellow it was relative to normal daylight and on the right how I actually perceived it:
https://fosstodon.org/@stim3on/110535700701027285
Simeon Schmauß (@[email protected])

Attached: 2 images @[email protected] yeah pretty crazy with all the wildfires! I'm curious though if you have seen the smoke yourself, did you notice your eyes adjusting to the overall reddish lighting? We had lots of Sahara dust blown over to Germany to while ago and it also tinted the sky very orange. However, after a while of being outside my eyes adjusted to it and it nearly looked like a "normal" overcast day. The left image is with daylight whitebalance and the right one roughly how I perceived it.

Fosstodon

@65dBnoise And yeah, most such attempts are basically just "winging" it and are not based on physical properties.

While the NASA images are technically based on physical properties of the cameras, they completely ignore the correct mapping of those values to a display. In that way they are not much more useful in creating an authentic view than the approximated hobbyist attempts.

@65dBnoise Even though the rovers have color calibration targets, I have not seen a single paper that uses these to calculate a correction for accurate colors. In principle they could be used for this, but they are far from optimal because there are too few targets with too little variation.

That said, they are actually used for calibration processes, but none that concern color accuracy. They are only used to calibrate radiometric data, i.e. how much light energy is entering the camera.

@65dBnoise NASA/ASU also produces "enhanced color" images which I think are more similar to the processing you are aiming for. These are not processed in a way that reflects how our eyes work, but for better color separation. This can certainly be useful for interpretations but won't produce an authentic colors.
@stim3on
Instead of enhanced color, I rather aim for familiar colors, and have the impression that such familiarity helps untrained or casual viewers see and understand better what goes on on Mars, the shape and texture of rocks, similarities with what one sees on Earth, clouds, frost, etc, by eliminating the reservation created by something that looks too alien. And when a dust storm hits, then the reddish haze caries a true (and very practical) meaning 😀