I’ve been sick all last week. That hasn’t stopped me from trying to process World View imagery in bulk on NASA’s Pleiades supercomputer. Right now I’m just trying to characterize how big of a challenge it is to process this large satellite data on a limited memory system for an upcoming proposal. I’m not pulling out all the tricks we have to insure that all parts of the image correlate. Still that hasn’t stopped ASP from producing this interesting elevation model of a section of Antarctica’s coastline, just off of Ross Island. Supposedly Marble Point Heliport is in this picture (QGIS told me it was the blue dot at the bottom of the coastline).
I’m using homography alignment, auto search range, parabola subpixel, and no hole filling. The output DEMs were rasterized at 5 meters per pixel. The crosses or fiducials in the image are posted 5 km apart. This represents a composite of 10 pairs of WV01 stereo imagery from 2009 to 2011 and no bundle adjustment or registration has been applied. The image itself is just a render in QGIS where the colorized DEM has had a hillshade render of the same DEM overlayed at 75% transparency.
I haven’t investigated why more of the mountains didn’t come out. When it looks like a whole elevation contour has been dropped, that’s likely because auto search range didn’t guess correctly. When it looks like a side of the mountain didn’t resolve, that’s likely because there was shadow or highlight saturation in the image. Possibly it could also be that ASP couldn’t correlate correctly on such a steep slope.
Ross Beyer, my co-worker at NASA, performed a Google Tech Talk early this month. It is now available online and you can watch it above. I don’t want to give any spoilers, but a certain stereo something is mentioned in this talk.
The Google community silently released a few new features for their Mars mode in Google Earth. MER-B, Opportunity, now has an updated traverse path thanks to a fellow at the Unmanned Spaceflight forum along with a new base map that Ross created. However I’m really excited about a new CTX Global Map that is available. Below is a screen shot:
From this high view you can see that that CTX hasn’t imaged all of Mars. This is expected. CTX isn’t trying to image all of Mars, it is simply the context imager for HiRISE. Meaning that CTX tends to roll tape only when HiRISE is. Never the less, the imagery is still beautiful and, in my opinion, shows more detail that the default base layer from an HRSC composite.
This mosaic was created by simply downloading all CTX data from NASA’s PDS servers and then calibrating and map projected the imagery with USGS’s ISIS software. The composite was then made with in house software from our team at NASA Ames Research Center. This is a Vision Workbench combination plus our Plate Filesystem. It is the same software we used to do a global MOC-NA and HiRISE mosaic for Microsoft’s World Wide Telescope. Unfortunately, I believe those servers have bit the dust. Regardless, if you have free time, I encourage you to check out the CTX Mosaic and Opportunity traverse in Google Earth. Click the planet, select “Mars”, and then in the bottom left select “CTX Mosaic” under “Global Maps”.