Perceptual Image Diff is an image comparison utility that makes use of a computational model of the human visual system to compare two images.
It's useful for running automated regression testing on images that are perceptually identical but have minor pixel noise from different random number generators or small changes to algorithms.
This project makes use of the Cross Platform Make Utility and the libtiff library. You will also need Subversion to obtain the source.
1. Edit CMakeLists.txt as necessary to point to libtiff
2. Type cmake .
3. Type make .
4. pdiff should be compiled for your target system
pdiff image1.tif image2.tif [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 oberserver 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 perceptably 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.
What's New in This Release:
· FreeImage IO code was patched in along with a -luminanceonly flag.
· PNG, TIFF, and JPG are now supported for input and output along with all other formats supported by FreeImage.