Photoprocessing - Brightness and Unsharp Mask

Wilhelm Sanke sanke at hrz.uni-kassel.de
Thu Jun 1 16:14:32 EDT 2006


Just found out where to place the "Bias" or "Shift" factor - an 
additional color value needed especially for relief-type filters - in 
Chipp's *no-external* script.

Unfortunately, adding this factor in the script that uses the DLL is not 
possible (it will will produce deviating results) as the factor has to 
be processed *inside* the equation for producing the new color values, 
meaning the bias factor cannot be added  to the imagedata *after* the 
DLL has been  used.

Execution time for the new no-external script (in my modified version of 
Chipp's  paradigmatic original - that takes care of the yellow-color 
shift and substitutes the use of arrays by direct addressing of 
imagedata, which in this case leads to a considerable speed gain) is 
about 10 seconds on a WindowsXP computer with 2 GHz.  This is of course 
very much slower than with a DLL or equivalent external for MacOS, but 
at any rate it may serve as an interim solution for the use of matrix 
filters with a size of 3 X 3 inside Metacard/Revolution.

The results of the use of 3 X 3-matrix filters with the new script in 
Revolution are absolutely identical to the use of equivalent filters in 
Photoshop and PaintPaint Pro. I tested this with a number of filters in 
all three applications.

Probably next week I will upload an new version of my "ImageFilterDemo" 
stack containing the new script and a number of additional useful filters.-

I repeat my requests - meanwhile supported by Richard Gaskin and 
probably others - for a DLL (and equivalent external on MacOS) for the 
use of 7 X 7-matrix filters - which of course include smaller settings 
like 3 X 3 filters - inside Revolution and the extra option for the use 
of Photoshop-compatible filters of the "8FB" type.

Regards,

Wilhelm Sanke
<http://www.sanke.org/MetaMedia>








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