| Optically Variable Device (OVD) is widely used in anti-counterfeiting with its beautiful color, abundantly variable optical effects and encryptions. Differing from conventional interferential photography, digital OVD is composed of tiny gratings exposed dot by dot in holographic materials with laser beam or e beam. It is more variable and useful with the applications of intelligent control and digital image processing. The thesis introduces techniques of fabricating Digital OVD and its application. Some designs are provided.The thesis advances a new way of making OVD with least square curve fitting. Large quantities of sophisticated guilloches can be produced without distortion. Corresponding procedure has programmed to design new patterns of OVD.
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