pnmpsnr

Compute the difference between two images. More information: https://netpbm.sourceforge.net/doc/pnmpsnr.html.

Compute the difference, i.e. the peak signal-to-noise ratio (PSNR) between two images:

pnmpsnr path/to/file1.pnm path/to/file2.pnm

Compare the color components rather than the luminance and chrominance components of the images:

pnmpsnr path/to/file1.pnm path/to/file2.pnm -rgb

Run in comparison mode, i.e. only output nomatch or match depending on whether the computing PSNR exceeds n or not:

pnmpsnr path/to/file1.pnm path/to/file2.pnm -target n

Run in comparison mode and compare the individual image components, i.e. Y, Cb, and Cr, to the corresponding thresholds:

pnmpsnr path/to/file1.pnm path/to/file2.pnm -target1 threshold_Y -target2 threshold_Cb -target3 threshold_Cr

Run in comparison mode and compare the individual image components, i.e. red, green, and blue to the corresponding thresholds:

pnmpsnr path/to/file1.pnm path/to/file2.pnm -rgb -target1 threshold_red -target2 threshold_green -target3 threshold_blue

pnmpsnr path/to/file1.pnm path/to/file2.pnm -machine