{"id":620651,"date":"2026-09-10T19:00:14","date_gmt":"2026-09-10T19:00:14","guid":{"rendered":"https:\/\/www.newsbeep.com\/ie\/620651\/"},"modified":"2026-09-10T19:00:14","modified_gmt":"2026-09-10T19:00:14","slug":"this-nasa-color-trick-was-meant-for-mars-now-its-unveiling-rock-art-on-earth","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/ie\/620651\/","title":{"rendered":"This NASA Color Trick Was Meant for Mars. Now It’s Unveiling Rock Art on Earth"},"content":{"rendered":"

In 2005, archaeologist Jon Harman was attending a conference on rock art when he came across an unexpected source of inspiration: images of Mars. One showed the planet\u2019s familiar rusty-red surface; another, created using a method developed at NASA, transformed the Martian landscape into a striking mosaic of red, green, and yellow, revealing remarkable detail. Harman immediately saw how the technique could help researchers study some of the world\u2019s oldest paintings.<\/p>\n

\"DstretchThe image of the Martian surface, with and without the decorrelation stretch technique applied. Credit: NASA <\/p>\n

The technique, known as decorrelation stretch, is used to enhance contrasts in digital imagery. It was first developed by researchers at NASA\u2019s Jet Propulsion Laboratory (JPL) in 1978 to improve the interpretation of high-correlation remote sensing and satellite imagery.<\/p>\n

\u201cI Googled it and found a NASA paper that explained how to do the algorithm,\u201d Harman said in a statement<\/a>. The archeologist first applied it to photos he had taken of rock art in Baja California, Mexico, revealing a new yellow figure in one image that seemed to appear out of nowhere. \u201cThat convinced me of the usefulness,\u201d he said.<\/p>\n

\"DstretchThe yellow figure appeared in this image from the Cave of San Borjitas in Baja California, Mexico. Credit: Harman <\/p>\n

Since then, Harman has used a software plug-in to enhance hundreds of images of ancient rock art.<\/p>\n

Space technology on Earth <\/p>\n

Rather than simply raising the contrast between colors, decorrelation stretch maps the original colors to a different, expanded range of colors. The technique is based on the Karhunen\u2013Lo\u00e8ve Transform, a theorem used in statistical analysis to maximize energy compaction (i.e., concentrating most of a signal\u2019s information into fewer components).<\/p>\n

In 1978, a supervisor of a digital image processing group at JPL, Jim Soha, proposed applying the Karhunen\u2013Lo\u00e8ve Transform to digital imagery for color enhancement.<\/p>\n

Later in 1996, Ronald Alley, who was a member of Soha\u2019s group at JPL, refined the process to make it faster and more accurate. It was Alley\u2019s paper<\/a> that Harman stumbled upon when he first began his own journey in adopting the technique to study rock art. \u201cSomeone had to write up a description of this thing so users would know what we were talking about,\u201d Alley said in a statement.<\/p>\n

Harman, who is now retired in Pacifica, California, has experience in medical imaging, in addition to a PhD in math from Berkeley, which gave him confidence he could figure it out. Using Alley\u2019s paper, Harman created the Dstretch software plug-in to enhance digital imagery.<\/p>\n

Uncovering the past <\/p>\n

The archeologist was able to tailor the decorrelation stretch method to rock art. \u201cI started playing around and found that by changing the color space I was working in, I could get good results in different images,\u201d he said.<\/p>\n

A color space is a range of numerically represented colors, such as the RGB color space (red-green-blue) commonly used on screen devices. The Dstretch plug-in includes custom color spaces that have proven useful with Harman\u2019s images of rock art.<\/p>\n

\"StoneSingaporean archaeologist Noel Hidalgo Tan used the Dstretch plug-in to discover more than 200 faded paintings around the Angkor Wat temple complex in Cambodia. Credit: Noel Hidalgo Tan <\/p>\n

Archaeologists have used Dstretch to discover images of bats and pigs in the ancient Egyptian cemetery of Beni Hassan, revealing animals rarely depicted in ancient Egyptian art. In Alberta, Canada\u2019s Writing-on-Stone Provincial Park, Dstretch revealed what could be considered an early form of graffiti tagging: a pictograph of a horse and rider that is believed to serve as a calling card from a Crow warrior, taunting his Blackfoot enemies.<\/p>\n

The plug-in software also uncovered about 15 previously undocumented figures and revealed new details in 28 others at the \u00c5rsand 1 site in western Norway. \u201cNo one really knows why people made the rock art they made, at least in many cases,\u201d Harman said of his fascination with the ancient paintings. \u201cAnd the symbols are quite strange.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"In 2005, archaeologist Jon Harman was attending a conference on rock art when he came across an unexpected…\n","protected":false},"author":2,"featured_media":620652,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23],"tags":[61,60,91,11830,82,247],"class_list":["post-620651","post","type-post","status-publish","format-standard","has-post-thumbnail","category-space","tag-ie","tag-ireland","tag-nasa","tag-satellites","tag-science","tag-space"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/620651","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/comments?post=620651"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/620651\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media\/620652"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media?parent=620651"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/categories?post=620651"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/tags?post=620651"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}