Mask fuzz artifacts in Color

[Mike in Rancho]

Sometimes, but off the top of my head not always, I see random artifacts when using mask fuzz. I believe it is only in the color module. The artifacts appear to bear no relation to the actual mask edges, and can just sort of appear anywhere, or scattered everywhere. Though in this screenshot I believe they are all within the green pixels. I would have to test more to see if that's always the case - it might be. The mask in this case (I screenshot that too) is sort of an amorphous blob surrounding the Cocoon, with a few internal stars deselected.

When this occurs, it precludes the technique of say, different balance or saturation amounts between star field and target, or target and surrounding background, etc., at least if you want to use fuzz to smooth possible blending. I don't usually do that except in rare needed cases, so I always forget about this bug.

Here's a screenshot I took of it happening last night. This is 1.8.511a, but this goes well back into at least 1.7. As said, I always just kind of forget about it until I need color mask fuzz, say oh yeah that's a bummer guess I can't do that...and then I forget about it again.

Mask Fuzz issue.jpg (397.76 KiB) Viewed 3502 times

[admin]

Hmmm...

When this happens, do the artifacts get "burned" into the image, or are they just displayed only (and don't affect the image). Thank you!

[Mike in Rancho]

Well, I thought they were burned in, because if you hit keep they are still there (in which case I would undo).

But after some playing around tonight I don't think they are permanent, perhaps just annoying?

I used the trusty ST M42 tutorial again like with the wild pixels. Same workflow to start, except now right to color after final AutoDev. After star sampling mask I inverted it, as if I planned to saturate the stars differently. Then, even just one click of fuzz, and color artifacts appear. Possibly all over -- changes to the channel bias sliders and saturation sliders make all sorts of funny things happen. If you keep, they remain. Same if you go into color again (inverted) to then color the stars.

However, denoise completely removes them, as do some other modules such as SS dimsmall, filter, shrink (although you really can't use the before/after toggle to see the "real" before and after). HDR, interestingly, just modifies the artifacts but doesn't erase them, again preventing you from seeing what's happening. Not that I normally go backwards to HDR after color anyway, but was just experimenting. But even in that case, the final denoise again makes them go away.

So..interesting. A pesky ghost that gets in the way but in the end not really there.

[admin]

Thank you! I have found the issue and it will be fixed in the next release.