Technique for Manipulating Satellite Photos Now Reveals Ancient Images (2025)

False colour composites were something I was introduced to in high school GIS and did a lot of in undergrad remote sensing. It was one of those Eureka! moments for me in terms of developing a better understanding of signals and signal processing, as well as sensors and data collection. Ie. absorbing the reality that the way in which my eyes (or any optical sensor) see the world is not canonical. Vegetation is red, not green!

It was also just the COOLEST THING EVER to swap infrared bands in LANDSAT ETM+ imagery and watch vegetation immediately pop out at you. It's what turned this sort of dull (at least for a teenager) geoscience into a kind of puzzle where you have to figure out how to bring the signal up out of the data.

You can do something similar in GIMP:

1) Colors > Components > Decompose > LAB

2) For the layers of the A/B (chroma) channels, Colors > Levels > "Auto Input Levels" (maximize the contrast), and move the mid point to the median.

3) Colors > Components > Compose > LAB

My first thought reading this headline was "Really? Nobody thought of this until now?" But reading further, the Dstretch plugin has been around since 2005 or so. And presumably people have been using contrast enhancement, color manipulation, multispectral imaging, etc. to uncover hidden images long before that.

So not exactly "news" at this point. But still a pretty cool success story.

It almost feels like a feature that should be built into the default camera app. For anyone wanting to conduct their own forensic analysis to determine how thoroughly their hotel room has been cleaned, for example (although personally I'd probably rather not know).

>But it’s also due to the chance intersection of one man’s hobby with his unrelated professional and educational background.

I wonder how many great inventions can be traced to this type of circumstances. I suspect more than we realize.

I'm surprised this is getting so much coverage; This is well known from medical imagining and whatnot, that you take a black&white/limited gamut space and spread it to the full perceivable gamut.

I tried to look for hidden rock art at Ankgor Wat by imaging with multiple bandpass filters and amplifying cross-spectral differences. I didn't succeed, but maybe I was in the wrong place. The shit guards there also didn't like me using a tripod while I changed filters, so it was also hasty.

“No one really knows why people made the rock art they made, at least in many cases,” Harman said

Well, it's obvious they really wanted to though. This isn't like marking on a wall with a Sharpie. They had to work at it to make it happen. The commitment alone is impressive even if it was just a "Grogg was here!"

Is there an imagemagick implementation that I can just throw into the pipeline?

DStretch is also really great at revealing painted ghost signs on old buildings.

Very Cool! I have a lot of 40MPx RAW pictures from the almost unreadable historic written walls in Delphi, Greece.

Let me test this with them.

See also: Eulerian Video Magnification (EVM) to amplify subtle motions and colour changes:

https://youtu.be/ONZcjs1Pjmk https://youtu.be/_qtzWNZApsw

Amazing. This will change how I take photos

any repo or link where other people can try?

This is based off a NASA article, which has an expanded version with more details here:

https://spinoff.nasa.gov/Manipulating_Satellite_Photos_Now_R...

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