Super-resolution challenge, Help requested by the science team |
Super-resolution challenge, Help requested by the science team |
Nov 1 2008, 12:16 AM
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#1
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Member Group: Members Posts: 696 Joined: 3-December 04 From: Boulder, Colorado, USA Member No.: 117 |
Greetings:
Here's another chance to maybe help out the New Horizons science team! We are planning the Pluto imaging sequence, and are considering the best strategy for squeezing the maximum resolution out of our images, including "super resolution" techniques, particularly for the side of Pluto that faces away from us at close approach, which we will see with a disk diameter of only about 120 pixels in our high-resolution camera LORRI. As some members of this forum have done impressive work with super-resolution processing of MER images, maybe you can try your hand with some synthetic "Pluto" images to see what the potential is? This may be more challenging than for MER, because our PSF is relatively broad, about 2 pixels wide. We want to know how many images to take of a given face of Pluto to get maximum benefit from super resolution techniques, if indeed they are useful at all. I plan to generate a bunch of synthetic images with slightly different pixel positioning and smear, and with realistic noise levels, and then make them available for experiments to see how well they can be combined and sharpened to improve the resolution. If you are interested in giving this a shot, let me know. Also let me know if you can work with 12-bit or 16-bit images, and if so what format is most convenient. I can easily make 16-bit FITS files, for instance. It may be that 8-bit PNGs will be adequate, too. Thanks, John. |
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Nov 13 2008, 09:54 AM
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#2
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Member Group: Members Posts: 293 Joined: 22-September 08 From: Spain Member No.: 4350 |
I had to try.
2x I used 5 images plus one to reduce noise. Mostly was about scaling up without interpolation, aligning the images, do some blending and several steps of gaussian blur and unsharp mask before scaling down --all very empirical. A real pro should be able to do better. |
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Nov 13 2008, 01:07 PM
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#3
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Interplanetary Dumpster Diver Group: Admin Posts: 4404 Joined: 17-February 04 From: Powell, TN Member No.: 33 |
Here is my take. I have versions with 4 frames, 6 frames, and 12. First, I deconvoluted the images to combat the broad PSF. I then blew the images up to 5x and sharpened them based on the new artificial point spread the enlargement created. I selectively stacked them, weighting them based on quality (I could probably do a bit better, but I was trying to hurry). After merging the image, I applied a light round of deconvolution based on a 4 pixel PSF and then reduced the images to 1.9x. A slight bit of sharpening was applied at this point.
4 Frames 6 Frames 12 Frames -------------------- |
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Nov 14 2008, 05:00 AM
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Interplanetary Dumpster Diver Group: Admin Posts: 4404 Joined: 17-February 04 From: Powell, TN Member No.: 33 |
Here is a view of Triton when it was 120 pixels across (shown here at about 2.5x). The inset shows two apparent plumes visible near the bottom of the terminator.
Now that I have worked on the Ganymede stack, might I ask if the image used is the NH frame from the same angle or generated from something else? The reason I ask is that the detail cutoff seems a bit odd compared to the Triton set and other real sets I have worked on. Namely, the technique does much better with high contrast details than low contrast details for obvious reasons. With the Ganymede images, the cutoff seems even. If it is from the lone NH frame, the reason is simple - I am smacking into the resolution limit of the image. -------------------- |
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