Wavelet Processing Example (GIMP)

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While I like to produce images that replicate a scene exactly, I am also fond of going to extremes in various ways.

One tool for such a way is called Wavelet Decomposition which allows the processing of parts of an image based only on their size of detail in the image. Meaning it is for example possible to adjust clouds without affecting twigs - or vice-versa. On the other hand it is possible to adjust skin details in portraits without messing with cheek tones or colors. In the GIMP, one can separately adjust up to eight detail sizes/"levels": 1,2,4,8,16,32,64px plus what's left over from those. Some apps e.g. RawTherapee can go up to much larger detail sizes than that (1024?)

As to clouds, here's a shot where I upped the contrast of level 64 to "bring out the clouds"

pole1-FSV-wavelets.jpg

For that same image opened in 7+residual levels, here's the residual level only i.e. all other levels turned off (no 'eye'):

pole1-FSV-wavelets-res-only.jpg

Out of interest, I turned off that residual and turned back on levels 1 to 7 ... voila:

pole1-FSV-wavelets-no-res.jpg

Quite interesting, I think.

I've read that going the other way (upping the small detail levels and lowering or turning off the larger details) can created pictures akin to drawings or etchings ...

Relevant link: Pat David: Wavelet Decompose (Again)

Wavelet cognoscenti here can suggest other combinations, I'm sure!
 
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