ppm3d - convert two PPM images into a red/blue 3d glasses PPM
ppm3d leftppmfile rightppmfile [horizontal_offset]
This program is part of Netpbm(1).
ppm3d reads two PPM images as input and produces a PPM as output, with the images overlapping by horizontal_offset pixels in blue/red format. The idea is that if you look at the image with 3-D glasses (glasses that admit only red through one eye and only green through the other), you see an image with depth. This is called a stereogram.
horizontal_offset defaults to 30 pixels. The input PPMs must be the same dimensions.
To make a different kind of stereogram, use pamstereogram. That makes a steregram that you view without special glasses, just by letting your eyes unfocus so that each eye sees different parts of the image.
Copyright (C) 1993 by David K. Drum.