公开(公告)号：US20070172094A1

公开(公告)日：2007-07-26

申请号：US10552075

申请日：2003-04-04

申请人： T. S. Ho ,  Jun Shen ,  K.K. Andrew Chow ,  W.M. Jeremiah Woon

发明人： T. S. Ho ,  Jun Shen ,  K.K. Andrew Chow ,  W.M. Jeremiah Woon

IPC分类号： G06K9/00

CPC分类号： G06T1/005 ,  G06T2201/0052 ,  G06T2201/0065 ,  G06T2201/0083

摘要： The invention provides a method and apparatus for watermarking a document, the method comprising: associating the document with an identification number; generating (70) a first set of numbers using a seed for the number generation comprising or derived from the identification number; applying a transform (62) to at least a portion of an image of the document to form a transform of the image; defining a second set of numbers comprising transform coefficients from the transform of the image; forming a modified second set of numbers based on the first set and the second set; substituting the modified second set for the second set in the transform of the image to form a modified transform (72); and applying an inverse (74) of the transform to the modified transform to thereby produce a modified image of the document; whereby the modified image of the document or an output of the modified image constitutes the watermarked document.

摘要翻译： 本发明提供了一种用于对文档进行水印的方法和装置，该方法包括：将文档与识别号码相关联; 使用包括所述识别号码或从所述识别号码导出的所述号码生成的种子来生成（70）第一组号码; 对文档的图像的至少一部分应用变换（62）以形成图像的变换; 从图像的变换定义包括变换系数的第二组数字; 基于第一组和第二组形成经修改的第二组编号; 在图像的变换中替换第二组的修改的第二组以形成修改的变换（72）; 以及将所述变换的逆（74）应用于所述修改的变换，从而产生所述文档的修改图像; 由此文件的修改图像或修改图像的输出构成加水印的文档。