README
======

The wavelet denoise plugin for The GIMP is an algorithm copied and slightly
altered from the UFRaw program (which inherited the algorithm from dcraw).
Instead of denoising all RGB channels at once the plugin implementation allows
to denoise the RGB channels individually and - even (a lot) more useful - to
denoise the YCbCr channels individually. The YCbCr conversion is nearly
lossless as the internal calculations are done in floating point numbers and
rounding errors are avoided.

LICENCE
-------

Copyright (C) 2008 by Marco Rossini. Distributed under the General Public
License. See the file COPYING which contains the license.

INSTALLATION
------------

See the file INSTALL for instructions how to install the plugin.

USAGE
-----

Once the plugin is installed successfully, the plugin can be found in The GIMP
using the menu "Filters->Enhance->Wavelet denoise". It works for both Grayscale
and RGB (full colour) images, including alpha channels. The plugin dialog
allows to adjust several parameters.

1. First, the choice has to be made over what colour model is to be used. There
   are two possibilities (maybe there will be more in the future):

     a) RGB     (red-green-blue)
     b) YCbCr   (luminance-bluechroma-redchroma)

   The YCbCr allows separate reduction of luminance and chroma (colour) noise.

2. The preview channel can be selected. Either all can be selected or
   individual ones which are then displayed in grayscale.

3. The sliders adjust the amount of denoising done for an individual channel.
   Only the channels selected for preview are ajustable, therefore you need to
   change the preview channel in order to adjust another denoise threshold.

For camera pictures I advise to use YCbCr mode (which is nearly lossless) and
to at least denoise the Cb and Cr channels to reduce the chroma (colour) noise.
If desired, the luminance noise can be reduced. This channel usually contains
most of the fine structures in the image and should mostly be left alone.
