Subject: gscan2pdf: Ability to binarize image (convert to 1-bit black/white) Package: gscan2pdf Version: 0.9.29 Severity: wishlist
When scanning text documents, many scanners produce better results when, if instead of scanning in lineart mode (1-bit black/white), documents are first scanned in grayscale (256-bit or higher) and then converted to black/white. There are many different algorithms for applying "dynamic binarization," the simplest being applying a theshold cutoff to each image pixel independent of neighboring pixels. The resulting black/white image should then be saved as a simple pbm instead of a multi-bit pam to save space (especially when emailing a pdf or archiving a scan) My suggestion would be to add a 'binarization' option to the Tools menu which would apply a default simple binarization rule. Color images would first need to be converted to grayscale, then converted to black/white after applying a per pixel theshold cutoff. Then the image should be saved as pbm instead of pam. According to its manual, PerlMagick supplies several key/value options: $image->Quantize(colors => '2', colorspace => 'Gray'); $image->Set(depth=>'1',monochrome=>'True',type=>'Bilevel',magick=>'pbm'); $image->Set( type => 'Bilevel' ); Unfortunately, these haven't worked for me, so its possible I misunderstand the PerlMagick library. I'm running Gentoo with media-gfx/imagemagick-6.5.7.0 and dev-lang/perl-5.10.1 -- To UNSUBSCRIBE, email to [email protected] with a subject of "unsubscribe". Trouble? Contact [email protected]
