A program that compares two images using a perceptually based image metric
Copyright (C) 2006 Yangli Hector Yee
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details in the file gpl.txt.
- Download cross platform make from http://www.cmake.org
- Download freeimage from https://sourceforge.net/projects/freeimage (mac:
brew install freeimage, ubuntu:
apt-get install libfreeimage-dev)
- To specify the install directory, use
make install DESTDIR="/home/me/mydist"
perceptualdiff image1.(tif | png) image2.(tif | png) [options] -verbose : Turns on verbose mode -fov deg : Field of view, deg, in degrees. Usually between 10.0 to 85.0. This controls how much of the screen the observer is seeing. Front row of a theatre has a field of view of around 25 degrees. Back row has a field of view of around 60 degrees. -threshold p : Sets the number of pixels, p, to reject. For example if p is 100, then the test fails if 100 or more pixels are perceptibly different. -gamma g : The gamma to use to convert to RGB linear space. Default is 2.2 -luminance l : The luminance of the display the observer is seeing. Default is 100 candela per meter squared -colorfactor : How much of color to use, 0.0 to 1.0, 0.0 = ignore color. -downsample : How many powers of two to down sample the image. -sum-errors : Print a sum of the luminance and color differences. -output foo.ppm : Saves the difference image to foo.ppm
Check that perceptualdiff is built with OpenMP support:
$ ./perceptualdiff | grep -i openmp OpenMP status: enabled
- Hector Yee, project administrator and originator - hectorgon.blogspot.com
- Scott Corley, for png file IO code
- Tobias Sauerwein, for make install, package_source Cmake configuration
- Cairo Team for bugfixes
- Jim Tilander, Rewrote the IO to use FreeImage.
- 1.0 - Initial distribution
- 1.0.1 - Fixed off by one convolution error and libpng interface to 1.2.8
- 1.0.2 - [jt] Converted the loading and saving routines to use FreeImage
- 1.1 - Added colorfactor and downsample options. Also always output difference file if requested. Always print out differing pixels even if the test passes.
- 1.1.1 - Turn off color test in low lighting conditions.
- 1.1.2 - Add OpenMP parallel processing support and fix bugs.