/usr/share/radiance/picdiff.cal is in radiance-materials 4R1+20120125-1.
This file is owned by root:root, with mode 0o644.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 | { RCSid $Id: picdiff.cal,v 1.2 2011/11/30 21:26:39 greg Exp $ }
{
Compute difference between luminance of two images.
Display towards red where first image is brighter,
and towards blue where second image is brighter.
29 August 1991
}
l1=li(1); l2=li(2);
pos(x):if(x,x,0);
avg=(l1+l2)/2;
dif=(l1-l2)/2;
ro=avg+dif;
go=pos(avg-dif*dif/2);
bo=avg-dif;
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