contrast by detail v wavelets


(Syv) #1

RT 5.4

I don’t understand the difference between the contrast by detail levels and the wavelets. They seem to do the same thing (to my eyes).

Is there some write-up that somebody can point me to?

Thanks

Syv


(Desmis) #2

You’re right CBDL and wavelet have points in common.

In the basic principle they both use a form of wavelet decomposition, but there are some dfferences

  • CBDL use a simplified wavelet decomposition on only 6 levels, if you tried to increase these number, that leads to artifacts

  • Wavalet use up to 10 levels, and use “Debauchies wavelet decomposition”

  • CBDL is limited to luminance channel

  • Wavelet use also, chroma channel and residual image, etc.


#3

So @jdc why wouldn’t merge these two into one powerful tool? It would make the theme more clear. The more similar albeit slightly different tools, the more confusing it is.


(Desmis) #4

@kazah7

Sometimes ago, we decided to create a special “tab” with complex tools (but what is complex tools ?)

  • Retinex
  • Ciecam
  • Wavelet

Why not others ? it’s a choice !
In this case “cbdl” / “wavelet”, the first is simple, intuitive ; the second is complex

jacques


(Glenn Butcher) #5

The tools reach the same objective, in different ways. The combination would probably be “contrast”, and there’d be checkboxes for CBDL and wavelets, you choose which. The only gain is the ready association of the two approaches to the objective.

This goes more to fundamental design philosophy of these toolsets we call “raw processors”. Digital imaging is a rather complex technology, and creative photographers tend to not revel in stuff like “full well saturation” and “non-local means”, so there’s a need for a lot of abstraction in the tools. As I read about and regard others’ use of Lightroom, I have come to appreciate what the Adobe programmers do to make good processing available to creative individuals. Thing is, they still need to respect the differences to their clientele, and they do so with what I call “roll-up” tools that actually stitch together a lot of different operations to do the fundamental thing in a pleasing way.

With the likes of Raw Therapee and darktable, however, you don’t get a lot of roll-up, the toolbox is chock-full of individual tools for you to figure out. I personally prefer that approach, but I’m also lamenting having to recently purchase a vehicle that doesn’t have manual transmission… :smiley:

While it takes a bit more work to learn such, I firmly believe the benefit of that is to learn a little more about how things work in the realm of imaging. And that learning is what allows you to more confidently use any tools to an intended effect.

Sorry for the discourse, it’s Saturday morning here and I’m in a contemplative mood…