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On Processing JunoCam images, methods and tips
GBAE001
post Mar 1 2019, 09:39 PM
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Hey all, I wanted to share with everyone my current newbie technique for processing JunoCam images. Iíve added one of your fantastic images that I wanted to emulate and wish for your advice to help improve my own skills and anyone else who reads this.

Note, I hosted my images on IMGR and embedding my images results in the error: "You are not allowed to use that image extension on this board. A valid format is: http://www.domain.com/picture.gif, an invalid format is: http://www.domain.com/picture.one.gif" I've tried looking this up and have no clue what it means.

In terms of knowledge, Iíll be using basic processing terms.

Choosing A Raw Image

I started processing from raws posted by the JunoCam team . However, some major improvements I noticed with other processed images was that they were much higher quality and had smooth planetary edges, where the JunoCam raw images from the size have very rough, pixelated edges.

Through some digging I found that most image wizards either make their own 3-D renders from the 2-D raws or get a raw image of someone elseís render. They leave the ďrawsĒ out for other people to use. Here on UMSF they can be found generally under each perijove (a pass of Jupiter by the spacecraft which produces more pretty pictures). Remember to credit the person who rendered your image, too!

I specifically took this projected raw by Brian Swift below. Iíll compare it on the right with a wonderfully processed version by Kevin Gill, which I will try and emulate.

https://imgur.com/S2EmVfF, https://imgur.com/83K0DPw

Processing

For reference, I am using GIMP 2.10, but this should work with Photoshop or other image processors.

Now, I smoothed the image, removed any image artifacts like hot pixels and sharpened it a bit to bring out the details. Also you might add a few adjustments to the colour and levels here and there, but itís a more subtle approach for this attempt.

https://imgur.com/3kHUyn3

Now, the first thing you might think is to increase the contrast to really bring out those clouds. But the issue is that it will remove your darker regions and blow out the top, like so:

https://imgur.com/jl3hFVb

So, the alternative is to use a mask layer and blending modes. Essentially, I want to stick a duplicate of Jupiter on top and blend it with the one below, but have it blend with different intensity to account for the brightness of the subject. This is to avoid losing some parts and blowing out others: I want it all exposed in the image, if I can. Iíll need to use a mask on the top layer for that. I made a mask by duplicating my image, converting it to grey-scale and applying a gaussian blur before inverting it. This will correlate pretty accurately with the areas I want to have the most intensity of blending and the least. Here's the masking layer I used:

https://imgur.com/5Jssi96

Now, for the actual layer to blend! I duplicated my image of Jupiter and applied the mask. I then played around with blending modes. Hard Light and Multiply seemed the best. I then adjusted levels of my blending layers. For this example, I used Hard Light and then duplicated the mask three times to increase the intensity of the effect.

https://imgur.com/lfLIcDN

Obviously, the effect is still nowhere near as vibrant and from my experimenting I wanted to ask the image wizards here how I might improve or completely ditch my process to produce something like the fantastic images I see around the net!

Best regards, Gabe.
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nprev
post Mar 2 2019, 12:52 AM
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Moved to Image Processing Techniques, edited title.


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