HiRise Imagery of Opportunity's trek, ...or, a blast from the past |
HiRise Imagery of Opportunity's trek, ...or, a blast from the past |
Dec 3 2006, 07:06 AM
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Senior Member Group: Members Posts: 2228 Joined: 1-December 04 From: Marble Falls, Texas, USA Member No.: 116 |
Like a lot of people, the new HiRise imagery has had me scrambling to learn about JPEG2000 (jp2) files, and trying to find software and plugins for manipulating and editing them. A lot of that discussion has been taking place in the MRO 2005 topic. We now have two MRO passes providing amazing stereo over much of Opportunity's trek, and it sounds as if we will soon have some Spirit coverage. I can hardly wait for that.
Anyway, I'm starting this thread for anyone wanting to post new HiRise imagery of places Opportunity has explored in the past. I'll start it with an anaglyph. Even though Meridiani is pretty flat, the MRO images were so fine that I really wanted to see how much detail I could get from them. Spectacular Victoria has already been nicely done, so I had to look elsewhere. I thought Beagle Crater and the transition to Victoria's annulus would be of interest to some people. I'll post this as a jpg that fits the forum size limit, but should we sometimes use the better jp2 format even though all users may not be prepared to view them? -------------------- ...Tom
I'm not a Space Fan, I'm a Space Exploration Enthusiast. |
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Dec 5 2006, 06:32 AM
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Senior Member Group: Members Posts: 2228 Joined: 1-December 04 From: Marble Falls, Texas, USA Member No.: 116 |
Excellent! How did some of us miss the bounces? What else is hiding in it?
The HiRise people have been busy lately, haven't they? The most recently released images are rightly stealing the show, but the caption from the Victoria anaglyph released today contained some useful information for the vertical exaggeration in stereo discussion. I think they provided the viewing angles for the first two passes over Victoria, which allow us to more accurately calculate the baseline from MRO's viewpoint, using Doug's estimation of the average vertical height of the passes. The angular separation between the views appears to be closer to 12 degrees, according to http://hiroc.lpl.arizona.edu//images/PSP/victoria.html Using simple geometry with the new angles, I calculate about 61 km for the baseline. Using 20 degrees, I essentially get the same number Doug did. Using the formula from the site I linked to earlier and this new data, I calculate a vertical exaggeration for the Victoria stereo as about 1.44 for someone with eyes spaced 7 cm apart and viewing the anaglyph from 18 inches (roughly 45 cm) from their monitor. If that person moved his/her eyes to about 12 inches from the screen, the vertical exaggeration should be around 1:1. Viewing it from 24 inches from the screen should result in a 2:1 vertical exaggeration, etc... I've created an Excel spreadsheet that can be used to play "what if" games with the variables. I tried to make it somewhat friendly for people who might not be familiar with Excel spreadsheets, so others could experiment with the variables. It can be easily modified for use with other stereo pairs, if you are familiar with spreadsheets. I have tested it enough to convince myself that it seems to agree qualitatively with what I see when viewing this pair of images. If anyone detects errors in it, please make me aware of them. I have been known to screw up. Vertical_Exaggeration_from_aerial_imagery.xls ( 36K ) Number of downloads: 2282 -------------------- ...Tom
I'm not a Space Fan, I'm a Space Exploration Enthusiast. |
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