[Digikam-users] A modern auto-fix?

Sat May 17 13:57:52 BST 2014

"Local contrast" is adjust and optimize contrast inside local zones of a 
picture in order to approach human eyes perception. That's exactly what 
the local contrast tool in DK does. 

The tone mapping process consists in matching repartition of colors from 
a 32 bits picture in a 8 bits one (for instance). That's totally different, even 
if some tone mapping algorythms have deep influence of local contrast. 

Best regards

Paulux

It's Windows, Carl, and the processor is a P.O.S. dual core that was meant 
for a laptop, but it's in my desktop.  My comment on speed was relative to 
the Canon program, and even the Windows Phone one.  But it's fine, it is 
what it is, I'm just grateful for the discovery.

On the topic, and further internet research, that the use of "Local 
Contrast" in dK might be a bit of a misnomer.  As mentioned, in PS, the 
plug-in does work with local contrast, not overall tones.  In fact, I'm seeing 
"Tone mapping" being used for what dK calls "Local Contrast."  Seems to 
be more accurate, grammatically.

Paul Verizzo 

On 5/17/2014 8:22 AM, Carl McGrath wrote:

PaulI scanned quickly for what OS you are running but did not find it; I run 
openSUSE 13.1dK 4.0.0 arrived a few days ago, with all the fixes Gilles 
reported that enable multicore.

Local Contrast and Sharpness tools now blazing fast(by comparison)

On 05/17/2014 07:58 AM, Paul Verizzo wrote:

Wow, that's it!  

I finally had time to locate some of the lousy original photos I had 
successfully improved with a couple of other programs, including, oddly, 
that Nokia (Windows Phone) Fix.  

Putzed with dK Local Contrast, works beautifully.  Just what I was after.  

I tried to find information and help in the dK PDF, but could not.  Searching 
online, "local contrast" brings up a lot of Photoslop entries, but they 
necessitate using layers and unsharp mask.  So much for the expensive 
program.  If I add "digikam" to the search, I just keep getting repeats from 
a blog posting.

I'd like to learn how to manually control adjustments for best results.

Any further help to be found?

Oh, yes.  Kind of slow, but if I factor in the need to open another program, 
rename, shuffle files, Local Contrast is another dK winner!

Thanks, Giles (and all others!)

Paul 

On 5/10/2014 12:11 PM, Gilles Caulier wrote:

digiKam has LocalContrast tool which make the same correction to
image. In fact it emulate pseudo HDR rendering.

Gilles Caulier

2014-05-10 18:07 GMT+02:00 Paul Verizzo <paulv at paulv.net>[1]: 
Background:  I've been in digital photography since 2000, decades of film
before and since.  I'm certainly familiar with the use of curves to correct
bad photos.  But so tedious, and if the photos are snapshots, hard to
justify the time.  It appears to me, although I can't prove it, that digital
cameras, discrete or within phones, seem to be doing a much better job
automatically adjusting curves than my old Minolta A2, for instance.

I recently became aware of a new free Canon program, My Image Garden, 
that
has a much improved Auto-fix than its forerunner.  As an example, a backlit
photo processed in MIG will bring up only the shadows while leaving the
normal and highlights alone.  It allegedly uses a zone by zone analysis.  It
is a terrible program in every other regard, clunky interface, bloated, etc.
But I used it for some recent pics to advantage.

Some of those pictures were originally on my Windows Phone 8, which I had
copied to the HD.  Before I deleted them from the phone, I poked around 
with
the options at that point.  I found an auto-fix, pushed the "button," and my
jaw dropped.  Literally.  A very dark, underexposed shot made perfect!  This
feature is within the Nokia programs!  It is so good, I can see myself
transferring photos from other sources into the phone for correction!  And
it's fast, even so.

I went back through the digiKam manual and looked on screen, and I see 
the
old standbys there, but nothing like what I've experienced with the above.
Oh, upon lots of research, I found a 2007 $40 program called Photoright 
that
upon test, seems to be doing similar zone adjustments.

Bottom lines:  Are my observations valid?  Do you think DK might get
something like this?  Oh, yes, all Windows although MIG is available for
Mac.

Thanks, Paul Verizzo

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