[Gimp-developer] McCann Retinex plugin with python

[John Fremlin]

"David Gowers" <00ai99 at gmail.com> writes:
[...]
> plug_in_decompose decomposes the image into a layer per channel.

Thanks

>> Searching the archives today I notice that Pedro Paf was suggesting
>> implementing it as a Summer of Code project - as the algorithm is very
>> simple (a day to make even starting no numpy or Gimp python
>> knowledge), what enhancements where being contemplated?
>
> I find this odd -- your whole email odd, in fact, because -- there is
> already a retinex plugin (found at Colours->Retinex;
> plug-ins/common/retinex.c in the GIMP source tree.).  If you want to
> add some enhancements, perhaps you could check that out first.

The retinex plugin is not documented. (As far as I can see?) What do the
different parameters to it mean? Even after looking at the paper it is
supposedly based on (multsclrtx.ps) I don't understand the
parameters. There are many different retinex algorithms based on
widely different principles; it is true that this one and the McCann
one are similar in some respects.

Obviously, I experimented with it a few times, but I couldn't get it
to work before I gave up.

The objective of my implementation of is to brighten dark areas of the
image while preserving detail, and it has a very noticeable effect.

Compare the outputs. Probably the best way to use my code is to select
the non-flatten option and adjust the opacity of the retinex layer
afterwards.