IEEE Trans Image Process. 2012 Jan;21(1):405-11. doi: 10.1109/TIP.2011.2155078. Epub 2011 May 19.
Halftone dot orientation modulation has recently been proposed as a method for data hiding in printed images. Extraction of data embedded with halftone orientation modulation is accomplished by computing, from the scanned hardcopy image, detection statistics that uniquely identify the embedded orientation. From a communications perspective, this data hiding setup forms an interesting class of channels with dot orientation as input and a vector of statistics as the output. This paper derives capacity expressions for these channels that allow for numerical evaluation of the capacity. Results provide significant insight for orientation modulation based print-scan resilient data hiding: the capacity varies significantly as a function of the image graylevel and experimentally observed error free data rates closely mirror the variation in capacity.
半调网点方向调制最近被提议作为一种在打印图像中嵌入数据的方法。通过从扫描的硬拷贝图像中计算唯一标识嵌入方向的检测统计信息，来提取嵌入的半调网点方向调制数据。从通信的角度来看，这种数据隐藏设置形成了一类有趣的通道，其中网点方向作为输入，统计向量作为输出。本文推导了这些通道的容量表达式，以便对容量进行数值评估。研究结果为基于方向调制的打印-扫描稳健数据隐藏提供了重要的见解：容量随图像灰度级显著变化，并且实验观察到的无差错数据速率与容量的变化非常吻合。
