pbmnoise
Generate white noise. tldr-pages
On several platforms
Several platforms
Generate a PGM image containing white noise
pbmnoise width height >path/to/output.pbmIdentifySpecify the seed for the pseudo-random number generator
pbmnoise width height -randomseed value >path/to/output.pbmIdentifySpecify the desired rate of white to black pixels
pbmnoise width height -ratio 1/3 >path/to/output.pbmIdentify