pnmpsnr

Compute the difference between two images.

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]

Produce machine-readable output

$ pnmpsnr [path/to/file1.pnm] [path/to/file2.pnm] -machine