Decorrelation Stretch

Decorrelation Stretch, a NASA Imaging Trick, Uncovers Hidden Angkor Wat Paintings

A NASA-developed image-processing method called decorrelation stretch, originally created to pull extra detail from satellite and Mars rover photos, has been repurposed to reveal ancient artwork invisible to the naked eye. Using this technique, a Singaporean archaeologist uncovered roughly 200 faded paintings at Angkor Wat between 2010 and 2012, including scenes of horseback riders and musicians. The method reached archaeology through Jon Harman, a medical imaging professional and rock-art hobbyist who adapted NASA's published algorithm into the widely used Dstretch software.

spinoff.nasa.gov · 2026-09-10

NASA's Mars imaging technique reveals hidden rock art on Earth

Scientists have applied a decorrelation stretch method originally developed by NASA to enhance Mars imagery, using it instead to uncover faded rock art on Earth. The technique works by remapping the original colors of an image into an expanded range rather than just boosting contrast, making subtle pigment differences visible to the human eye.

gizmodo.com · 2026-09-10