[ANN] Image Filter Demo
Wilhelm Sanke
sanke at hrz.uni-kassel.de
Fri Jun 23 17:24:54 EDT 2006
While I am still trying to bring my Image Filter Tool into a presentable
format - I think I will need another two or three weeks before going
public - I offer a preview gallery that I have just uploaded to
<http://www.sanke.org/MetaMedia>: Scroll down at the left until link
"Image Filter Gallery" or go directly to
<http://www.sanke.org/MetaMedia/ImageFilterGallery.htm>.
Some of the applied filters are adapted from 3X3 to 9X9 matrix formats,
others had to be scripted from scratch (like the Kuwahara filter) for
Revolution, a number of created filters were transferred from my
Colorpattern Toolkit and adapted to the handling of imagedata.
Filters greater than 3X3 or such filters that use additional factors
(like the "bias" or "offset" values needed for instance to create
reliefs) cannot be used with Derek Bump's or Chipp's Windows DLL, but
all filters - including the 3X3 format - can also be used without any
external, meaning that they can be used on any platform with a number of
"no-external" routines. I have now streamlined the no-external scripts
for applying the filters down to 7 seconds (2 GHz Windows computer) on
the average. Many of the filters that do not apply matrices at all can
be much faster, up to less than 1 second.
To reduce execution time from the original 90 seconds of the
no-external script I started with, one of the steps was to abandon the
intermediate use of arrays, another to take a number of computations out
of loops.
The latest gain in speed occurred when I substituted
" # put binaryEncode("CCCC",255,tRed,tGreen,tBlue) after tconvData"
by
"put numtochar(tRed) into char (ti + (tj+2)) of tconvdata
put numtochar(tGreen) into char (ti + (tj+3)) of tconvdata
put numtochar(tBlue) into char (ti + (tj+4) )of tconvdata".
This caused a speed gain of two seconds alone.
I may also be mentioned that many filters are slower - by 20 to 33 % -
in the Revolution IDE compared to the Metacard IDE. Standalones show the
same difference of speed.
There are also many filters not shown in the gallery that make
extensive use of mirroring, enlarging, decreasing, stretching,
duplicating parts of images and many forms of color change.
I has been an interesting and educating exercise for me to gain some
insights about filters mostly by intensive web searches.
I repeat my query for more and improved externals for faster filter
handling. I very much doubt I could familiarize myself with the art of
producing DLLs in the near future, so I hope for support from other list
members or even from the Revolution crew.
Best regards,
Wilhelm Sanke
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