8.6. Mars Exploration Rovers

The Mars Exploration Rovers (MER) have several cameras onboard that acquire stereo pairs. The images come with CAHVOR camera models, that have local positions and orientations.

ASP can create point clouds and textured meshes from these cameras. DEMs cannot be created right away, unlike for MSL, which has geolocation information (Section 8.12.5), but an SfM solution is likely to work as in Section 9.3.

8.6.1. PANCAM, NAVCAM, HAZCAM

These are cameras on the rover and are all processed the same way. It is preferred to use NAVCAM images, as those have less distortion than the HAZCAM.

../_images/mer_mesh.png

Fig. 8.4 Left input image and produced textured mesh.

8.6.1.1. Recipe

Download the data from the the PDS Image Atlas.

wget https://planetarydata.jpl.nasa.gov/img/data/mer/mer2no_0xxx/data/sol0766/edr/2n194370551effap00p0675l0m1.img
wget https://planetarydata.jpl.nasa.gov/img/data/mer/mer2no_0xxx/data/sol0766/edr/2n194370551effap00p0675r0m1.img

Create the CAHVOR cameras:

mer2camera 2n194370551effap00p0675l0m1.img
mer2camera 2n194370551effap00p0675r0m1.img

Run stereo (Section 16.51) and create a mesh with point2mesh (Section 16.58):

parallel_stereo                       \
   2n194370551effap00p0675l0m1.img    \
   2n194370551effap00p0675r0m1.img    \
   2n194370551effap00p0675l0m1.cahvor \
   2n194370551effap00p0675r0m1.cahvor \
   run/run

 point2mesh -s 2 --texture-step-size 2 \
   run/run-PC.tif run/run-L.tif

See Section 6 for a discussion about various speed-vs-quality choices.

It is suggested to filter out points that are not triangulated well because they are too far using the parallel_stereo option --min-triangulation-angle (Section 17).

For finer-grained control, can use:

--universe-center camera --near-universe-radius 0.7 \
   --far-universe-radius 80.0

These may be suggested as well:

--alignment-method epipolar --force-use-entire-range