| 摘要 |
<p>A security document and its method of preparation are provided wherein a security image area on the face of the document is designated. The security image area comprises a two-dimensional array of security image blocks. Security image elements and the complementary security image elements in respective security image blocks are arranged such that the security image element and the complementary security image element portions occupy respective first and second percentages of each of the security image blocks to define respective characteristic relative occupation values (CROVs) for each security image block.</p> |
