Juno PDS data |
Juno PDS data |
Jan 8 2016, 10:15 PM
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#1
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Administrator Group: Admin Posts: 5172 Joined: 4-August 05 From: Pasadena, CA, USA, Earth Member No.: 454 |
There is now PDS-format JunoCam cruise and Earth flyby data available; it's been submitted to the PDS, but MSSS has gone ahead and posted it on their website. I've created an index page to it here. Unlike my usual index pages, there aren't any thumbnails because of the odd nature of JunoCam images, with their long skinny shapes and interleaved framelets. I haven't played much with these data because it's a bit beyond my skill -- I look forward to seeing what any of you can do with it.
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Jun 28 2016, 12:14 PM
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#2
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Senior Member Group: Members Posts: 2346 Joined: 7-December 12 Member No.: 6780 |
This is a 16-fold brightness-stretched and 2-fold enlarged crop of 2013107_00C048:
It shows one copy of a pattern which repeats each 3x128=384 pixel rows in the raw swath. Those repetitive patterns are mostly caused by hot pixels. But there exist some repetitive spots of different type, too. The 3x128 pixels are resulting from exposures made of three color bands times 128 pixels framelet height. This is a 16-fold enlarged crop: It shows a vertical line of 4 bright pixels. This line is the result of one hot pixel on the CCD copied 4-times by the TDI mechanism. It indicates, that 4 TDI steps have been applied for this image. - TDI 4 is hard for finding many stars. TDI 64 and TDI 80 are much better-suited for this purpose. The 16x16 noisy block indicates, that the image has been compressed lossily on macroblocks (tiles) of 16x16 pixels. When looking for real objects, first mark all repetitive patterns, or clean the image from these patterns. Then decompose the swath into framelets of height 128 pixels, grouped into exposures of 3 framelets. Insert a gap of 27 pixels between neighbouring framelets within one exposure. Assign a color channel to each framelet within each exposure. Shift the exposures vertically, until you get a match of corresponding features (about 114 pixels, give or take a few). Use the valid color channel of each exposure to obtain full rgb coverage. The result will be a first draft of an RGB image. I'd recommend to use 2013282_000C91 (aka EFB01), showing Earth's moon, as a first exercise. The first 22 slides of the pdf I've provided a few weeks ago should apply to moon and star RGB images, as well. Spacecraft trajectory and rotation of the target objects can be neglected for distant targets. You may use weights for the colors in order to adjust the raw colors, if you use EDRs; the weights for the colors are likely to undergo refined calibration. |
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