Images of the surface of Mars with a never before obtained resolution have been created by UK researchers using a novel stacking technique.
The team from University College London created images of the landing site of the lost British Beagle 2 lander with a five times greater resolution than previously achieved. The images, obtained by stacking multiple satellite pictures of the same spot, match the quality of those obtained by Martian rovers despite being taken from a considerable distance.
"We now have the equivalent of drone-eye vision anywhere on the surface of Mars where there are enough clear repeat pictures,” said Professor Jan-Peter Muller from the UCL Mullard Space Science Laboratory, one of the authors of a paper describing the new technique. “It allows us to see objects in much sharper focus from orbit than ever before and the picture quality is comparable to that obtained from landers.”
Most images obtained by orbiting telescopes only provide images with a resolution of 25cm at best. However, by stacking multiple pictures of the same spot taken from different angles, the UCL team managed to increase this resolution to 5cm. That means that while in a single shot no objects smaller than 25 cm could be seen, once the multiple images are stacked, objects as small as 5cm suddenly become visible.
The technique, called super-resolution restoration, could be used to search for other artefacts from past failed landings, as well as to identify safe landing locations for future rover missions. The view from orbit has an advantage over surface-based exploration as it covers a much wider area.
"As more pictures are collected, we will see increasing evidence of the kind we have only seen from the three successful rover missions to date,” Muller said. “This will be a game changer and the start of a new era in planetary exploration."
For Mars, where the surface usually takes decades to millions of years to change, the images can be captured over a period of ten years and still achieve a high resolution. For planets with a dynamically changing atmosphere such as Earth, the images for each stack would have to be obtained only seconds apart.
For the Martian images, the team used pictures provided by Nasa’s HiRISE camera - the same instrument that enabled the discovery of the failed Beagle 2 rover last year.
"This technique has huge potential to improve our knowledge of a planet's surface from multiple remotely sensed images,” said Yu Tao, research associate at UCL and lead author of the paper. “In the future, we will be able to recreate rover-scale images anywhere on the surface of Mars and other planets from repeat image stacks".