Technique for Manipulating Satellite Photos Now Reveals Ancient Images (2025)
summary
A NASA image-processing technique called decorrelation stretch is now being used by archaeologists to uncover faded ancient rock art and other historical artifacts. By expanding the range of colors in digital images, the algorithm makes subtle differences in contrast visible that are otherwise invisible to the human eye. This transition from planetary science to archaeology was driven by a hobbyist with a mathematical background who translated the complex NASA paper into accessible software. The resulting tools allow researchers to identify previously unknown paintings and structures across the globe.
key points
- The decorrelation stretch algorithm maps original colors to a wider, expanded range rather than simply increasing contrast, which reveals hidden details in faded imagery.
- The Dstretch software was developed by Jon Harman, who combined his PhD in mathematics and medical imaging experience to turn a JPL research paper into a practical plug-in and mobile app.
- Beyond rock art, the technology has been successfully applied to identifying buried building foundations in Greece, uncovering tattoos on mummies, and tracking volcanic plumes via infrared imagery.
who should read it
History enthusiasts and technology fans who are interested in how scientific tools from one field are adapted for use in other disciplines.
discussion warm
consensus
Commenters generally agree that while the technique of decorrelation stretching is not new to specialists in remote sensing and GIS, it is a powerful tool for uncovering hidden visual data in rock art and other surfaces. There is a shared appreciation for the role of mentorship and specialized education in sparking lifelong passions for these technical fields. The sentiment is largely positive, blending technical curiosity with nostalgia for the impact of supportive teachers.
top insight
The discussion reveals that the utility of decorrelation stretching extends far beyond archaeology, with practical applications in astrophotography, detecting ghost signs on old buildings, and analyzing faded graffiti. One user explains how to replicate similar contrast-enhancement effects in GIMP using the LAB colorspace to isolate and amplify color information without affecting luminance. This demonstrates that the underlying principle of signal processing can be applied using common consumer software.
Generated by an LLM from the article and thread. Check the sources before relying on it.