latexdiff is a Perl script, which compares two latex files and marks up significant differences between them (i.e. a diff for latex files). Various options are available for visual markup using standard latex packages such as "color.sty". Changes not directly affecting visible text, for example in formatting commands, are still marked in the latex source.
PerceptualDiff is an image comparison utility that makes use of a computational model of the human visual system to compare two images.
This software is released under the GNU General Public License.
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