Beginner level projection Options

[adamg]

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

[Bill Dudney]

This is very cool. Beautiful work!

Thanks!

It has been so much fun building this stuff

Is this you on twitter @TheSeaning? If so I love your work. It's a big part of what got me motivated to come back to this in my free time.

[Brian Swift]

Finally got to the point that I have something cool to show.

Definitely cool.
What is the development environment/toolset?

[Bill Dudney]

Definitely cool.
What is the development environment/toolset?

Swift/Xcode/metal, runs on iOS, macOS and tvOS.

[Bill Dudney]

Hi All,

Finally got to the point that I have something cool to show. Still plenty more to do but I'm stoked at where I am. It's interactive, projected onto a sphere, and will display any image from any data set from the PDS archive. The rainbow in the back is the normal to help me be sure I'm putting the data in roughly the correct spot.

Couldn't have done it without your help. Thanks again!

I finally had time to come back to this and get further along. Thought I'd share the latest UI. This is JNCE_2019202_21C00010_V01 from data set 12. Plenty more to do but good progress.