admin wrote: ↑Fri Feb 02, 2024 2:33 am
- Wavelet sharpening is about isolating and manipulating specific frequencies (like a graphic equalizer).
Hi Ivo!
Well, I had a graphic equalizer once. Once.
And while I did toy around with electronics a little bit in my youth, I was never the type to have, ya know, an oscilloscope. Also, historically, my soldering has always been functional but not pretty. At all.
So even from a 1D or audio stream standpoint, there's a lot of Greek there for me.
decay wrote: ↑Fri Feb 02, 2024 12:32 pm
(What is UM?)
Unsharp Mask. Sorry for the acronym.
decay wrote: ↑Fri Feb 02, 2024 12:32 pm
We should think about what we want to know ... and what to do first ... I'm confused
I will check your app out. I think what we want is a good sample image, or set of sample images. Yes synthetic or even terrestrial images may be useful as a tutorial sample, but maybe also we can find an astro image with some features that would be good for showing things (and also have stars so we can run SVD on it)?
Last night I tried to do more reading on wavelets, and mostly some detailed write-ups on how R6 is probably functioning. Then I played with some finished images and ran Gimp default settings UM on it, then opened in PI to run the 3D graph generator on a ROI of the Flame for before and after. Indeed it just seemed to raise the mountains and ridges and perhaps deepen the canyons of the 3D graph.
Now...I think that is expected behavior but adds another wrinkle to my thinking. In addition to steepening the transitions, the data also seemed to be expanding its range on the Z axis.
jlh wrote: ↑Fri Feb 02, 2024 1:40 pm
That is, it is essentially a correction using the intrinsic data available and not just more or less an enhancement of the image.
Maye not quite, yes I accept Sharpen is in the intrinsic category, but also enhancing, along with Contrast and HDR, and my initial query was trying to divvy those up even more, thinking Sharpen to be further into enhancing and away from data fidelity than those other two. Which Dietmar answered early on as maybe they really should all be considered about the same.
Which is fine, and rehabilitates sharpening a little bit in my mind. At least for wavelets and ST sharpen, but I'm still not very confident in UM.
Last night I fiddled with Sharpen some, and I believe I found one of my perceptual problems with it. Default is large structure, but also has all wavelet sliders maxed out at 100%. Well, #5 and sure #4 are pretty large scale, and that (leaving things default) is why I have mostly seen what looks mostly like a simple brightening of bright stuff. And in a lot of cases I didn't find terribly useful, or like anything I would see in R6 doing planets.
Of course R6 starts with everything at zero.
Well, duh! I'm an idiot.
It seems to me that, especially with large selected in screen 1, for a lot of our datasets it's almost mandatory to zero out the #5 and #4 scale sliders, and maybe even #3 as well. And with scaling more appropriate to the portions of the target that are of interest, the strength can be jacked up as well.
I'm such a bonehead.