Juno at Jupiter, mission events as they unfold |
Juno at Jupiter, mission events as they unfold |
Jul 5 2016, 07:53 PM
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Merciless Robot Group: Admin Posts: 8785 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
This topic will consist of discussion of Juno operations post-JOI until end of mission, currently anticipated in Feb 2018.
-------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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Jul 25 2016, 08:39 PM
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#2
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Senior Member Group: Members Posts: 2346 Joined: 7-December 12 Member No.: 6780 |
@Brian Burns: Thanks! I hope so, too.
I'm simulating the behaviour of the camera as good as I can, and calc back from an output pixel position to pixel positions in the EDRs to obtain color information for the output pixel. For the sequence I've moved the green channel of Jupiter's centroid to the center of the respective image to obtain alignment along the sequence. @Floyd: Thank you! My camera simulation is not yet quite perfect; I needed to make a decision between investing more time to narrow down the parameters, or releasing images with imperfect RGB alignment. So I get some RGB misalignment. The apparent exchanged alignment error is essentialy the same misalignment; the difference between the two is dark shadow on bright background vs. bright object on dark background; this causes the observed effect. My schedule was completing an RMS minimization for the parameters somewhere between end of July and end of August, with end of October as deadline, when the regular science mission begins. But I thought releasing processed images of imperfect quality is better than releasing no processed images. With a delay of several months I may be able to pin down the camera parameters to the best possible within a given family of camera models. |
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Jul 25 2016, 09:25 PM
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Senior Member Group: Members Posts: 2542 Joined: 13-September 05 Member No.: 497 |
I'm simulating the behaviour of the camera as good as I can, and calc back from an output pixel position to pixel positions in the EDRs to obtain color information for the output pixel. Despite the color misalignment, considering the method it's quite impressive and indicative of the amount of work you've done that this product is as well-aligned as it is. I made the decision with my movie processing to not try to model the camera at all, which actually works better in most cases while completely choking on images where the planet landed on framelet boundaries -- those had to be fixed by hand. Are you using the C kernel data or coming up with some independent estimate of s/c orientation based only on camera images? BTW, there is a large high-latitude shadow of Ganymede in frame 1196-1199 or so. -------------------- Disclaimer: This post is based on public information only. Any opinions are my own.
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Jul 31 2016, 12:39 AM
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Senior Member Group: Members Posts: 2346 Joined: 7-December 12 Member No.: 6780 |
Despite the color misalignment... this product is as well-aligned as it is. I made the decision with my movie processing to not try to model the camera at all, which actually works better in most cases... A still rudimentary analysis of the color misalignment helped already to improve the alignment considerably. Thus far I've just rendered a few hundred images with the refined parameters. Despite not yet being the best possible parameters in the sense of an overall optimization, the results already look good. Here an arbitrarily chosen cropped example, previous vs. refined version: Respective parameters of the previous and the refined version: JNCE_2016178_00C1310_V01_proc007.BMP.LBL ( 1.21K ) Number of downloads: 253 JNCE_2016178_00C1310_V01_proc012.BMP.LBL ( 1.21K ) Number of downloads: 254 I've used image 196 to find a good x/z pinhole scale together with an according y-position of the optical axis, and image 200 to re-adjust Juno's rotation (angular velocity) in terms of interframe delay. For image 196, I got a residual mismatch of the blue channel relative to red and green of about 1/8 raw pixel, while red and green matched rather accurate in the 1/100 raw pixel range. - I've defined mismatches via centroid displacements between color channels. For image 200, I've refined the angular velocity parameter just visually. |
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