East side of Cape York, Sol 3040 - 3056 Options

[Tesheiner]

Well, my impression is that the trek south, crossing by the east side of Cape York, has started.
Here's a crude navcam mosaic taken on sol 3040. Don't you think this side of the planet is also beautiful?

[neorobo]

Forgive me if this has already been posted (I did a quick search but can't seem to track down the specific posts), but I have a question about the glare. Has there been any publications or information NASA has published about the effects of glare on the visual odometry for Opportunity or Spirit? Has this been much of an issue on Mars for MER visodom? I have an understanding why glare affects feature tracking, I'm more interested in how it has affected Oppy or Spirit specifically. I'm in the process of writing a research proposal and this information would be very valuable. Even if it's just something qualitative to get the wheels turning, no pun intended Thanks.

Rob

[RoverDriver]

I have never seen any VO image that was affected by glare from either rover. And tosol VO failure is not due to glare either. Typically we point the cameras down at about 30 deg below the horizon to
have a good view of the tracks. With such a low elevation angle it is difficult to have glare. Even Autonav pointing is pretty low as well. Here, as I was saying earlier, there were no features to track (remember the on-board processing uses 256x256 pixel images) and there were no track markings on the ground. Even if we had pointed teh NAVCAMs straight down it would have been likely that VO would have failed.

The glare in the post-drive NAVCAMs is mostly due to the dust deposition on the lens. Post drive NAVs are usually taken at -17 deg elevation and in early afternoon. Leave a digital camera for 8+ years in the desert, lens cap off, then try to take a picture late in the afternoon while pointing the camera at the horizon to the West. Assuming the shutter release still works after 8 years, that is.

One of the optical engineers (Reg Wilson) published a paper on the effects of dust deposits on the lens and CCD sensor. I don't have a reference, but if you look up Reg Wilson on the JPL web site very likely he has that paper listed.

Paolo

[neorobo]

I have never seen any VO image that was affected by glare from either rover. And tosol VO failure is not due to glare either. Typically we point the cameras down at about 30 deg below the horizon to
have a good view of the tracks. With such a low elevation angle it is difficult to have glare. Even Autonav pointing is pretty low as well. Here, as I was saying earlier, there were no features to track (remember the on-board processing uses 256x256 pixel images) and there were no track markings on the ground. Even if we had pointed teh NAVCAMs straight down it would have been likely that VO would have failed.

The glare in the post-drive NAVCAMs is mostly due to the dust deposition on the lens. Post drive NAVs are usually taken at -17 deg elevation and in early afternoon. Leave a digital camera for 8+ years in the desert, lens cap off, then try to take a picture late in the afternoon while pointing the camera at the horizon to the West. Assuming the shutter release still works after 8 years, that is.

One of the optical engineers (Reg Wilson) published a paper on the effects of dust deposits on the lens and CCD sensor. I don't have a reference, but if you look up Reg Wilson on the JPL web site very likely he has that paper listed.

Paolo

Thanks for the reply Paolo, very useful information. I wonder, when operating the rover are lighting conditions a constraint on the time period it may drive (I'd think at some point the images become too dark to operate visual odometry properly), or if other things restrict it before it comes to that, like power?

Very interesting to see that the rover is barely leaving any tracks! I love that 8+ years later Opportunity is still amazing us.

Rob

[RoverDriver]

Thanks for the reply Paolo, very useful information. I wonder, when operating the rover are lighting conditions a constraint on the time period it may drive (I'd think at some point the images become too dark to operate visual odometry properly), or if other things restrict it before it comes to that, like power?

Very interesting to see that the rover is barely leaving any tracks! I love that 8+ years later Opportunity is still amazing us.

Rob

Lighting conditions have never been an issue for driving as we typically try to drive "blind" (no VO or Autonav). Lighting conditions are usually always analyzed when using the MI as we try to avoid frames where part of the target is in direct sunlight and part is in shadow. If it is required, we sometimes change the IDD configuration to use a different wrist position and very rarely we have moved teh time when the IDD sequence begins to have more favorable Sun position. This is what happened so far but I guess that our current position it might not be a bad idea to think about lighting conditions for driving as well.

Paolo