Pro Tip: How to Create a Mars Pano with 36 NASA Images 3

by Dan Smigrod • Tips and Tricks, TourWrist News • Tags: ,

[Editor's Note: Professional Photographer Steve Perry describes how he stitched and published images shot by NASA Mars Rover, Curiosity.]

by Steve Perry

So at the end of a cross-country trip, have you ever taken a moment to use your cell phone camera to snap an arm’s-length picture of yourself in front of whatever local landmark there may be?  Well, after a long 8½ month, 55,000,000 km flight, that’s exactly what NASA’s Mars Science Laboratory (MSL) Rover, Curiosity, did recently.

On Sunday, August 5th, after successfully surviving a 7-minute entry, descent and landing phase, Curiosity settled into its landing spot in Gale Crater on Mars to begin a 2-year mission to search for signs that at one time, there may have been conditions suitable to foster life on the Red Planet.

But before anything else could be done, Curiosity needed to snap that picture of itself and call home.

Mars 360 Pano Stitched From 36 Images

That “picture” actually amounted to over 2,000 frames from its various Navcam, Mastcam and hazard avoidance cameras, documenting the landing and its new neighborhood from various angles.  Included in that assortment of shots was a 36-frame panorama automatically captured from its right Navcam (a separate, but less ideal set was also shot with the left Navcam).  I used these 36 images to create Curiosity’s Self Portrait on TourWrist.  These – and all of the other – original RAW (jpg) images taken by Curiosity can be downloaded from the NASA MSL Website, and are public domain.

The Navcam pair are two black & white cameras mounted side by side on the Curiosity instrument mast and will be used primarily for generating 3D perspectives of the local terrain for navigation; however on day 2 of the mission, they were used to capture this first complete panorama.  These two cameras each have a focal length of 14.67mm, but have a 35mm camera equivalent of about a 40mm focal length. This gives the camera about a 45-degree field of view, yielding frames 1,200 pixels square, according to NASA-provided Curiosity specs.

When building a panorama with NASA images, the first order of business is patience.  Even though my working frames were shot during Sol 2 (Martian mission day two), all 36 full resolution frames were not transmitted by the rover until over a week later.  (This is thanks to the whopping Mars-Earth data bandwidth constraints of 128 kbps!  Separate thumbnails do make it down sooner, so you do know what you can eventually count on.)

So once I had the full batch of 36 images, I immediately dropped them into PTGui Pro software and began the usual stitching process: loading the images, aligning them (after figuring out the correct lens settings), and optimizing.  However for whatever reason, my alignment was pretty far off.  One issue was the relatively poor definition of details in the distance due to the jpg RAW files yielding so many compression artifacts that the software had difficulty aligning control points.  That, and the fact that the rover came to rest at about a 5-degree angle, making alignment of the horizon a challenge. (Pro tip: even if your tripod cost $2.5 billion, make sure that it’s level. It will save you time in post production.)

Curiosity Right Navcam [Image Courtesy of: NASA/Jet Propulsion Laboratory (JPL)-California Institute of Technology (Caltech)/Cornell/Arizona State University

So after spending some time setting and correcting manual control points between all of the frames, the second big challenge was to mask rover details to either hide or force details into alignment.  By my count, there were about 39 masks.

The next step was to export the stitched panorama to a tif file for use in Adobe Photoshop software.  After a little noise and artifact reduction with Topaz Labs DeNoise and DeJpeg software, I then blended and clone stamped the remaining horizon flaws that I couldn’t correct in PTGui Pro.  Because this first pano had almost no sky, I then used Topaz Labs ReMask software to eliminate what little sky there was, as well as create an artificial horizon in places where there was none.  So with the terrain separated from the sky, I then went in search of another sky.

The day after this first black & white pano was shot, NASA used their 34mm color MastCam camera to do a very limited pano (far less coverage than the Navcam material).  These images however did have color samplings of the sky and ground, which I used to create an artificial sky, as well as a reference color to shade the ground.

From Photoshop, I then imported the flattened tif into Garden Gnome Pano2VR software, and then proceeded to clean up certain parts of the pano, including the zenith (sky) and the nadir (ground).  If you look at this Mars Panorama Editor view on TourWrist, you can see that there was a pretty considerable void in frame 28 which luckily I was able to clone over with ground and a piece of the wheel.  As any panographer will know, reducing the footprint in the nadir is essential for a successful pano, however I don’t believe NASA was too worried about that when it designed their instrument mast (I won’t even get into the parallax issue that the forward and side mounting of the camera on the mast causes).

So even though this first attempt at using NASA supplied content to build a pano took quite a few hours to build, the word that I’m hearing from NASA is that future pano sets will improve as they begin using the color Mastcam; making the stitching turnaround a bit less arduous.

So as Curiosity begins its trek through the hills and valleys of Gale Crater on its way to Aeolis Mons (aka Mount Sharp), I’m optimistic that we will be treated to some truly breathtaking vistas — the likes of which we have never seen before.

About the Author: Steve Perry is a Southern California based professional photographer, video editor and production design consultant, with over 30 years working in the broadcast and cable TV businesses.  In 2012, Steve began exploring the potential of panoramic photography, and now incorporates this medium in his production portfolio on TourWrist.  

More Mars Panos

360 ‘PanoCam’ Pano: Curiosity’s Self Portrait on Mars. Images Courtesy of: NASA/Jet Propulsion Laboratory (JPL)-California Institute of Technology (Caltech)/Cornell/Arizona State University/Post Production: Steve Perry

360 ‘PanoCam’ Pano (“Before”): This 360 pano is a screenshot from the PTGui Pro Panorama Editor screen. Coverage of the horizon (such as it is) is fairly straightforward, except for alignment issues because the rover is sitting on about a 5-degree angle. However it’s the rover’s distorted and parallax prone coverage which was the biggest challenge in the control point, masking and forcing process. Screen grab courtesy of Steve Perry. Images Courtesy of: NASA/Jet Propulsion Laboratory (JPL)-California Institute of Technology (Caltech)/Cornell/Arizona State University.