image to 3d printable heightmap/lithophane by Amanda Ghassaei May 2013 detailed documentation at http://www.instructables.com/id/3D-Printed-Photograph/ This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.
aqover/Lithograph3DPrint
converts an image to a 3d printable heightmap or lithophane (http://en.wikipedia.org/wiki/Lithophane)
Processing