[X] My Assistant

[aldo12xu]

I generated a few stereo images of the etched terrain from Viking to Victoria craters. I'm not 100 percent confident in my renditions, simply because the landscape looks pretty bizarre: undulating terrain with parallel east-west trending ridges that even affect the ejecta around Victoria and Erebus.

Here are my source images. Thanks to Alan for pointing them out to me:

Left: http://www.msss.com/moc_gallery/r10_r15/im...5/R1500822.html
Right: http://moc.rlproject.com/end_vic_1m.jpg

Anaglyph:
733 Kb: http://www.marsgeo.com/Photos/Opportunity/Etched_LRa_s.jpg
2.0 Mb: http://www.marsgeo.com/Photos/Opportunity/Etched_LRa.jpg

Parallel method:
267 Kb: http://www.marsgeo.com/Photos/Opportunity/Etched_LR_s.jpg
1.6 Mb: http://www.marsgeo.com/Photos/Opportunity/Etched_LR.jpg

Crosseyed method:
265 Kb: http://www.marsgeo.com/Photos/Opportunity/Etched_LRx_s.jpg
1.6 Mb: http://www.marsgeo.com/Photos/Opportunity/Etched_LRx.jpg

[edstrick]

Regarding the topographic relief artifacts in the stereopair of the etched terrain: I've seen extended abstracts from either Lunar and Planetary Science Meetings, Mars Workshops <mostly linked to from the LPI Lunar and Planetary Institute> or International Mars Conference a couple years ago on this.

The MOC Camera on Mars Global Surveyor was designed to take vertical monoscopic black and white images with the highest resolution practical. It's geometric precision is perfectly adequate for that purpose but is far from ideal for stereo work, especially in very flat terrain. Also, the spacecraft is *NOT* a stable platform, wobbling slightly in attitude during the "push-broom" sweep of the field-of-view of the camera's line-scan CCD across the scene. These imperfections put various "corregations" in stereo pairs and there isn't enough precise info on attitude in the telemetry to precisely correct for it. The experts have had a hard tiem trying to get artifact-free stereopairs from the MOC images, despite access to camera calibration files and the spacecraft engineering telemetry.

Basically, we're trying to do something the camera wasn't designed to do.

[jdub]

While it is true that the MGS is a "wobbly'" platform and can often result in wavy stereo images like this, it's certainly not true all the time. The MOC is in fact perfectly capable of superb stereo pairs for anaglyphs or for free viewing. The experts should only have trouble trying to use these images for digital terrain models. A bigger problem for stereo image creation arises from the fact that there are months or years between images of the same terrain. Any differences in the images such as mismatched sun angles (different season, different time of day), surface patterns that are present in one image but not the other (such as dust devil tracks or new slope streaks) or differing amounts of dust in the atmosphere can all play havoc with stereo pairs. Image quality also varies widely.

Even with all of this there are still literally hundreds of great stereo pairs available. Here is an example of some Terra Meridiani craters not too far from Opportunity:



Here's an Aram Chaos anaglyph:



Lots more here:MarsUnearthed.com

You'll need your red/CYAN glasses.