Beginner level projection |
Beginner level projection |
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#1
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Junior Member ![]() ![]() Group: Members Posts: 31 Joined: 31-October 19 Member No.: 8699 ![]() |
Hi,
I'm trying to do the mapping just using SPICE for the Junocam images rather than going through ISIS. It might seem like I'm making life difficult for myself but I just wanted to make sure I'm doing the bare minimum amount of processing so it looks as close to a non-spinny-push-frame image as I can. I'm making all the beginner mistakes but I can't seem to figure out what they are so I was hoping someone might give me a hint? First I want to figure out how far Jupiter is because I want to have anything that didn't hit Jupiter get mapped to a sphere that hits Jupiter. This means any lens effects can get mapped in space near where they originated from which should hopefully make the edges of the planet seem less processed: [jupiterPos, jupiterLt] = spice.spkpos('JUPITER', et0, 'JUNO_SPACECRAFT', 'NONE', 'JUNO') jupiterDistance = np.linalg.norm(jupiterPos) Then I go through all the undistorted Junocam pixel vectors and figure Jupiter intercept points in the IAU_JUPITER frame so now I have a point cloud of all the planet mapped pixels: [point, trgepc, srfvec, found ] = spice.sincpt( 'Ellipsoid', 'JUPITER', et, 'IAU_JUPITER', 'LT+S', 'JUNO_SPACECRAFT', 'JUNO_JUNOCAM', v) If it didn't find an intersection then I figure out where that invisible sphere is going to be by extending out the pixel vector by the separation and move that to the IAU_JUPITER frame: direction = np.array(v) pos = direction*jupiterDistance/np.linalg.norm(direction) rotationMatrix = spice.pxform('JUNO_JUNOCAM','IAU_JUPITER',et-jupiterLt) pos = spice.mxv(rotationMatrix, pos) It works terribly! I seem to have a timing error in the frame offsets that seems suspiciously close to the light time between Jupiter and Juno and the sphere that catches all the sincpt misses is completely miles off. I've been staring at the code for a while and not figuring my mistake, I was hoping someone might point out where I've gone wrong. Many thanks Adam |
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#2
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![]() IMG to PNG GOD ![]() ![]() ![]() ![]() Group: Moderator Posts: 2251 Joined: 19-February 04 From: Near fire and ice Member No.: 38 ![]() |
I haven't looked at the code in any detail so I don't know if this is of relevance here but my single biggest lesson with SPICE is probably: Understand the SPICE reference frames and use them a lot (of course there are many more things you need to know). Knowing how to use them results in shorter, simpler code among other things (and almost certainly fewer bugs).
That said, I often find discussion like the posts above interesting. |
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#3
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Newbie ![]() Group: Members Posts: 15 Joined: 1-August 20 Member No.: 8847 ![]() |
I haven't looked at the code in any detail so I don't know if this is of relevance here but my single biggest lesson with SPICE is probably: Understand the SPICE reference frames and use them a lot (of course there are many more things you need to know). Knowing how to use them results in shorter, simpler code among other things (and almost certainly fewer bugs). That said, I often find discussion like the posts above interesting. Thanks Bjorn, I'm glad I could provide an interesting conversation ![]() I love it, it's so much fun to build things like this! And thanks for all you've done with the Juno data. It is one of the many inspirations of me wanting to keep going. TTFN, -bd |
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