ICMP is a program for comparing images and printing statistics of the difference between the images. It is handy for comparing original and decompressed images to evaluate lossy compression performance. PSNR, RMSE, max difference and mean absolute error are all computed and printed. The format in which the statistics are printed is configurable on the command line. ICMP can also be given the name of a compressed data file and print its size in bytes and in bits per pixel.

ICMP supports image files in RAW (raster scan with no header or encoding) or PGM format. Color images are supported in RAW or PPM format.

All documentation is built into the executable. Use the -h option.

ICMP should compile with just about any C compiler. I have compiled it with gcc-2.7.2, gcc-2.95.2, egcs-1.1.2 and cc on HPUX, Solaris and SunOS. If your C compiler will not compile ICMP, please e-mail me the error messages it generates.

ICMP is free software licensed under the GNU General Public License, version 2.0, available here GNU GPL, and here COPYING.

Download the source: icmp.c