[SOLVED] real name of "parabola" window function is "Welch"

Post any defects you find in the released or beta versions of the ImageMagick software here. Include the ImageMagick version, OS, and any command-line required to reproduce the problem. Got a patch for a bug? Post it here.
Post Reply
NicolasRobidoux
Posts: 1944
Joined: 2010-08-28T11:16:00-07:00
Authentication code: 8675308
Location: Montreal, Canada

[SOLVED] real name of "parabola" window function is "Welch"

Post by NicolasRobidoux »

It's "Welch", not "Welsh".
http://www.cg.tuwien.ac.at/~theussl/DA/node34.html
http://www.cis.rit.edu/resources/softwa ... ndows.html
http://paulbourke.net/miscellaneous/windows/
http://mathworld.wolfram.com/WelchApodi ... ction.html
And, based on the tests of my student Adam Turcotte, it is one of the very best window functions, based on its "reconstructor" power for subcritical ("very slightly blurry") images. (Cosine is really good, too; so are Sinc (Lanczos) and Hamming (this last one, only when using many lobes).) (Warning: reconstruction tests do not measure visual quality, only something best described as "accuracy".)
Last edited by NicolasRobidoux on 2012-08-21T05:10:21-07:00, edited 7 times in total.
NicolasRobidoux
Posts: 1944
Joined: 2010-08-28T11:16:00-07:00
Authentication code: 8675308
Location: Montreal, Canada

Re: Real name of the "parabola" window function is "Welch"

Post by NicolasRobidoux »

In the same vein, you guys are aware that the real name of the "Hanning" window function is "Hann", yes?
"Hanning" is a common misspelling, probably arising from the fact that the Hann window is quite similar to the Hamming window.
User avatar
anthony
Posts: 8883
Joined: 2004-05-31T19:27:03-07:00
Authentication code: 8675308
Location: Brisbane, Australia

Re: The real name of the "parabola" window function is "Welc

Post by anthony »

I added the correct spellings as 'alternative' names in IMv6 (unable to do a complete fix for library backward compatibilty)

And a complete correction with 'alternate miss-spellings' in IMv7 (with defines for programming compatibility)

I think I have everything -- it certainly compiled fine.

As such
convert -list filter
or for IMv7...
magick -list filter
now lists
Hann and Welch
rather than
Hanning and Welsh
But the later miss-spells will continue to work, even though it is not listed in the option list.
Anthony Thyssen -- Webmaster for ImageMagick Example Pages
https://imagemagick.org/Usage/
NicolasRobidoux
Posts: 1944
Joined: 2010-08-28T11:16:00-07:00
Authentication code: 8675308
Location: Montreal, Canada

Re: [SOLVED] real name of "parabola" window function is "Wel

Post by NicolasRobidoux »

Thank you Anthony.
User avatar
anthony
Posts: 8883
Joined: 2004-05-31T19:27:03-07:00
Authentication code: 8675308
Location: Brisbane, Australia

Re: [SOLVED] real name of "parabola" window function is "Wel

Post by anthony »

The graphs on resize examples have also now been updated. Give the official site a bit of time though.
Anthony Thyssen -- Webmaster for ImageMagick Example Pages
https://imagemagick.org/Usage/
Post Reply