Assembling Voyager movies Options

[Brian Burns]

Hello,

I'm a bit new here - I recently started on a project which I thought would be fun, to assemble movies of all the Voyager flybys. Of course, with 70k+ images, it would have to be automated as much as possible, and the results would be fairly crude. But there's enough information to make some rough black and white and color movies with one segment per target, and eventually combine them all into one movie.

The main task is getting the images properly centered, since the cameras don't point right at the target - there are still some jitters at the moment, so it needs some more stabilization. But in any case, here are some slightly bumpy rides along with Voyager - these are from versions 0.3-0.34 -

Ariel (Uranus)
https://www.youtube.com/watch?v=HeGgH34v8R4

Uranus
https://www.youtube.com/watch?v=0RLGadmvc40

Neptune
https://www.youtube.com/watch?v=HlU2_NOgoew

Assembling a color movie is a matter of combining the images that seem to go together (since it's not explicit in the data) - this is a first attempt at that. There are frames that lack certain channels, so colors are pretty off at points - later it could borrow a nearby image when a channel is missing.

Neptune, colorized
https://www.youtube.com/watch?v=c8O2BKqM0Qc

The goal is to generate the movies with as little manual annotation as possible - there are parts that need it though, like handling images with multiple targets, slowing down the movie at certain points, and turning off the centering at closest approach.

Anyway, just wanted to share what I've got so far - hopefully one day it will be able to make a nice, stable movie of all the flybys, with some appropriate music. Once the code is a little more stable I'll post the project on GitHub - it's written in Python with OpenCV, SciPy, and IMG2PNG.

-Brian

[Brian Burns]

Just an update - I've been switching things over to use IMQ files instead of the newer IMG/LBL files, so I can use ISIS with them (so can colorize all the images).

Some issues I've run into with ISIS -

IMG/LBL files not handled
https://isis.astrogeology.usgs.gov/fixit/issues/4345

cam2map doesn't handle distant targets
https://isis.astrogeology.usgs.gov/fixit/issues/4376

Some IMQ files throw error unable to initialize camera model
https://isis.astrogeology.usgs.gov/fixit/issues/4352

Some IMQ files throw error invalid time string due to UNKNOWN image time
https://isis.astrogeology.usgs.gov/fixit/issues/4414

I'm still working on getting distant targets to work with ISIS - ie when a target doesn't take up the whole image frame, and the pointing is off as with Voyager, the different ISIS camera alignment programs won't work. At the moment I can shift the image so the target appears where the pointing kernel expects it to be and then run cam2map correctly, but this would end up losing information as the target fills more of the frame. So I'm trying to rotate the camera matrix with a new ISIS program so it will point correctly at the target, but so far haven't been able to get it to work - it winds up pointing way out of the image frame.

Another problem is the amount of time needed to run cam2map, which projects from an image to a cylindrical map, using attached SPICE data - for a 1600x800 map it takes about 40 seconds on my i3 laptop - if I were to run this on every image it would take 73000*40/60/60/24 = 34 days. I looked through the code and it seems to be written more for clarity than speed, which is fine - I do need a faster computer though. I'd initially tried doing the projections in Python with OpenCV using the remap function, and at least for the simple case of a distant spherical target it would project to a 1600x800 map in 15 seconds - which would take a total of 13 days. I think cam2map is also doing corrections for the Voyager camera distortions though.

So I was thinking of cheating a bit and using predefined cylindrical maps for the missing info - it wouldn't work with Jupiter or Neptune due to cloud movements etc, but maybe it would work for things like Io, Europa and Triton. For Jupiter maybe I could run cam2map - for Voyager 1 and 2 it would be on the order of 30k images - with a faster computer using all cores maybe it wouldn't be too bad.

Still have the issue ahead of correcting the camera pointing for closeup images, though as far as I understand it the ISIS program jigsaw should handle those cases. Then I'd be able to pull back the missing info from the map and colorize the images - fortunately map2cam runs quickly. Not sure how fast jigsaw runs though... I'm guessing it's slow - it uses iteration to solve for the camera matrix.

And also need to handle the different map scales - e.g. at the highest resolution the map of Jupiter would be enormous, so will need to just focus on the relevant regions.

Was also thinking of using the cylindrical maps to animate the flybys, e.g. simulating the view as if Voyager was taking pictures of each target the whole time - would slow things down so the terrain would go by slowly underneath. Might be good for making a short movie of all the flybys.

Edit:

Aaaand another error - some IMQ files seem to be corrupted?

voy2isis throws **USER ERROR** Unable to set PDS file.
https://isis.astrogeology.usgs.gov/fixit/issues/4421