The key problem of visible watermarking is how to balance the watermark visibility, the security and the quality of marked image. In this paper, an adaptive visible watermarking scheme in document images using two-stage Mamdani fuzzy inference system (FIS) is presented. Firstly, four attribute parameters of document images including the neighborhood gray-scale value (G), skewness (Sk), entropy value (En) and standard deviation (Std) are defined as visible watermark embedding criteria. Secondly, the FIS1 and FIS2 are designed with different input and output parameters to get the adaptive intensity factors. In order to avoid the visible watermark being removed by the binary removal attack, the gray-scale uniform distribution method is used to remove the peak of the probability logarithmic histogram after the FIS1 stage. Finally, according to the results of FIS2 stage, the change of histogram is not obvious. To evaluate and analyze the performance of this scheme, the proposed scheme is compared with other previous visible watermarking schemes, and experiment results show that the presented one has better visual effect and less distortion.

中文翻译：

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基于两阶段模糊推理系统的文档图像可见水印

可见水印的关键问题是如何平衡水印的可见性、安全性和标记图像的质量。在本文中，提出了一种使用两阶段 Mamdani 模糊推理系统（FIS）的文档图像中的自适应可见水印方案。首先，定义文档图像的邻域灰度值（G）、偏度（Sk）、熵值（En）和标准差（Std）四个属性参数作为可见水印嵌入标准。其次，FIS1和FIS2设计了不同的输入和输出参数，以获得自适应强度因子。为了避免可见水印被二值去除攻击去除，采用灰度均匀分布方法去除FIS1阶段后概率对数直方图的峰值。最后，根据FIS2阶段的结果，直方图的变化并不明显。为了评估和分析该方案的性能，将所提出的方案与以往的其他可见水印方案进行了比较，实验结果表明所提出的方案具有更好的视觉效果和更少的失真。