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

The tools to reveal hidden historical details are now accessible for $20.

A technique developed by NASA's Jet Propulsion Laboratory, called decorrelation stretch, is being used to reveal ancient, faded images on artifacts and in archaeological sites. Originally designed to enhance satellite imagery, the method sharpens contrasts in digital photos, making subtle details visible. Jon Harman, inspired by its application to Mars rover images, created the Dstretch plug-in for image analysis software and later mobile apps. This tool has enabled the discovery of hundreds of previously unseen paintings at Angkor Wat, the uncovering of hidden figures in Norwegian rock art, and the identification of animals in Egyptian mummies. It has also been applied to aerial imagery to locate potential archaeological sites in Greece and to enhance images of tattoos on mummified remains. The technique, rooted in mathematical principles and building upon earlier work by JPL scientists, has found diverse applications beyond its initial remote sensing purpose.

The widespread adoption of NASA's decorrelation stretch technique, through tools like Dstretch, signifies a new era in accessible archaeological discovery. This method's ability to bring faded images to light democratizes the process of uncovering historical information, previously requiring specialized equipment or expert interpretation. It suggests a growing trend of leveraging advanced digital image processing, initially developed for space exploration, for terrestrial historical research and preservation.

This development will affect how historical sites and artifacts are studied and understood, potentially leading to a significant increase in documented discoveries. Researchers and enthusiasts alike can now contribute to historical understanding with readily available software. The continued evolution of such techniques hints at future possibilities for non-invasive historical analysis, bridging the gap between scientific innovation and our comprehension of the past.