25 January 2011 UV fluorescence encoded image using two halftoning strategies
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A method is provided for embedding a UV fluorescent watermark in a color halftone image printed on paper. The described method implements two different strategies to halftone a watermark region and a background region. One strategy uses dot-on-dot halftoning to maximize the usage of black ink and minimize ink dispersion, while the other strategy uses successive-filling halftoning to maximize ink dispersion. An accurate color look-up-table (LUT) is built to directly transform the colorant values for one halftoning strategy to the colorant values for the other strategy. With the color transformation applied on one region, the binary outputs in both watermark and background regions halftoned with different strategies exhibit similar color appearance under normal lighting condition. However, under UV illumination, due to the fluorescent effect caused by different paper coverages in two regions, the embedded watermark becomes clearly visible.
© (2011) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Yonghui Zhao, Yonghui Zhao, Shen-Ge Wang, Shen-Ge Wang, } "UV fluorescence encoded image using two halftoning strategies", Proc. SPIE 7866, Color Imaging XVI: Displaying, Processing, Hardcopy, and Applications, 78661D (25 January 2011); doi: 10.1117/12.872758; https://doi.org/10.1117/12.872758


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