发明名称 |
Low visibility watermark using time decay fluorescence |
摘要 |
Media is embedded with an out-of-phase digital watermark. A first component of the digital watermark is printed using a first ultraviolet (UV) ink. The first UV ink includes a first fluorescence decay time. The second digital watermark component is inverted with respect to the first component and is printed using a second UV ink. The second ink includes a second fluorescence decay time, which is longer than the first decay time. The embedded media is illuminated with a UV pulse. The watermark is detected after the first emission decay time, but before the second emission decay time. The watermark is fragile under steady-state UV illumination since the inverted watermark component cancels the non-inverted component.
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申请公布号 |
US2002090112(A1) |
申请公布日期 |
2002.07.11 |
申请号 |
US20010945243 |
申请日期 |
2001.08.31 |
申请人 |
REED ALASTAIR M.;BERKLEY LOU H. |
发明人 |
REED ALASTAIR M.;BERKLEY LOU H. |
分类号 |
B42D15/10;G06F17/30;G06K9/20;G06K17/00;G06K19/06;G06K19/14;G06K19/18;G06T1/00;G07C9/00;G07D7/00;G07D7/12;G07F7/08;G07F7/10;G07F17/16;G10L19/00;G11B20/00;H04N1/00;H04N1/32;H04N7/26;H04Q7/38;(IPC1-7):G06K9/00 |
主分类号 |
B42D15/10 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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