| 摘要 |
This invention relates generally to document protection methods and product. More specifically, the present invention relates to a method for hiding information in a document by means of a latent image or message, which is practically invisible to the naked eye and may only be revealed through use of a matching viewing device. The present invention further relates to a method for creating original documents containing latent messages, which are revealed when the document is read by a viewing device. In one embodiment, print elements such as lines, dots, spots, swirls, or images are used to form covert information. The covert information print elements are disposed at an angle to print elements of a background, thus creating a covert document. In another embodiment, print elements of the covert information are used with a solid background. |
