perceptualdiff(1) on Linux
The text fd2bdbfac114, as Debian 11 (Bullseye), Debian 10 (Buster), Debian 9 (Stretch), Debian 8 (Jessie), Debian 7 (Wheezy) shipped it.
compare images using a perceptually based image metric
Flags it lists
-
-fov -
-gamma -
-luminance -
-output -
-threshold -
-verbose