Hologravure as a computer-generated and laser engraved scratch hologram

We presented “hologravure” as the generalization of a scratch hologram, generated by computer from a three-dimensional (3D) model by using an appropriate software, and laser-drawing with a conventional engraver-laser system. For making this type of computer-generated hologram, neither diffractive optics, nor mask pattern or photo-reduction of a transparency onto a high resolution film plate is needed. The shape of a 3D virtual object is encoded in a two-dimensional (2D) multiple circular-scratch drawing. A computer program was created for generating the holograms. Hologravures representing several 3D models are engraved on different materials, and the quality of the lines traced by the CO2 laser is considered. Sheets of acrylic, polycarbonate, glass and thermo-resistant pieces of acetate were tested. Reconstructed images of all this computer-generated and laser engraved holograms and also of computer assisted and hand-drawn scratch holograms, synthesized by means of the same software are shown.