Hi,
Shlomi Fish <shlomif@xxxxxxxxxxxxxxxxxxx> writes:
> Does RLE in "RLE Guassian Blur" stands for Run-Length Encoding? Also,
> does IIR in "IIR G. B." stands for Infinite Impluse Responce?
>
> I'm preparing a lecture about the GIMP so I'd like to know what the
> initials mean. There's nothing in the code or documentation to explain it.
Nothing? From plug-ins/common/gauss_rle.c (around line 632):
/* Determine a run-length encoded version of the row */
run_length_encode (sp + b, buf, bytes, height);
Looks to me as if RLE could indeed mean Run-Lenght Encoding.
"Grokking The GIMP" goes into more detail:
Gaussian Blur (IIR) and Gaussian Blur (RLE) produce exactly the same
results. However, Gaussian Blur (RLE) runs faster on images that have
broad constant-valued pixel regions because it exploits a compression
technique known as run length encoding. For photographs of real world
scenes, Gaussian Blur (RLE) provides no advantage and might even run
slower than Gaussian Blur (IIR).
Finding out what IIR actually means proved to be more difficult. I'd say
however your guess was right and it's actually an "Infinite Impulse
Response" filter.
Salut, Sven
