This image was taken by Curiosity’s Front Hazcam: Left B on Sol 387. Image Credit: NASA/JPL-Caltech

Onboard focus merge of targeted surface feature on Mars. Image Credit: NASA/JPL-Caltech/MSSS

NASA’s Curiosity Mars rover continues its wheeling southwestward toward Mount Sharp, in the middle of Gale Crater.

Just released imagery shows the robot in action, including the use of an onboard focusing procedure.

The process involves the Mars Hand Lens Imager (MAHLI) aboard Curiosity. Images are created by merging two to eight images previously taken by the MAHLI, located on the turret at the end of the rover’s robotic arm.

Curiosity performed the merge on September 8, 2013, Sol 387 of the Mars Science Laboratory Mission, at 01:29:42 UTC.

The onboard focus merge is sometimes performed on images acquired the same sol as the merge, and sometimes uses pictures obtained on an earlier sol.

Features into focus

Focus merging is a method to make a composite of images of the same target acquired at different focus positions to bring all (or, as many as possible) features into focus in a single image.

Because the MAHLI focus merge is performed on Mars, it also serves as a means to reduce the number of images sent back to Earth. Each focus merge produces two images: a color, best-focus product and a black-and-white image that scientists can use to estimate focus position for each element of the best focus product.

Up to eight images can be merged, reducing the number of images returned to Earth to two.

Major science objective

After landing inside Gale Crater in August 2012, Curiosity drove eastward to the Glenelg area.

Once there, the robot accomplished the mission’s major science objective of finding evidence for an ancient wet environment that had conditions favorable for microbial life.

At Mount Sharp, scientists anticipate finding evidence about how the ancient Martian environment changed and evolved.

By Leonard David