公开(公告)号：US20050041051A1

公开(公告)日：2005-02-24

申请号：US10644472

申请日：2003-08-20

申请人： Ricardo de Queiroz ,  Robert Loce ,  Karen Braun ,  Raja Bala

发明人： Ricardo de Queiroz ,  Robert Loce ,  Karen Braun ,  Raja Bala

IPC分类号： H04N1/32 ,  B41J2/205

CPC分类号： B41J2/205 ,  H04N1/32144 ,  H04N1/32251 ,  H04N1/32267 ,  H04N1/32309

摘要： What is disclosed is a method for digital watermarking in a calibrated printing path and comprises: first receiving a pixel possessing color values from an input image; receiving a plurality of information bits to be encoded at a corresponding pixel in an output image. Then, one of at least two different GCR functions are selected where the selection is based on the state of the received information bits. The number of GCR functions to be selected from is dependent on the number of possible states of the information bits intended to be encoded at each image pixel and preferably equals the number of states of the information bits intended to be encoded at each image pixel such that the GCR spatially varies across the output image. Further, at least two GCR functions are optimized to carry information and information bits intended to be encoded within the output image are represented with a tag. CMYK values are then generated using the selected GCR function and the color values. These CMYK values are assigned to a corresponding pixel in the output image. The information bits to be encoded at a given pixel indicate the type of object to which that pixel belongs, such as: graphics, picture, text, line art, etc. The output image, when printed, exhibits the property that substantially similar colors occurring at different spatial locations in the input image are produced with substantially different CMYK combinations in the print. Preferably, a parameterized function is used for the GCR function and the encoded state sets the parameter of the function. Information bits should be redundantly encoded throughout the output image. Regions that cannot be encoded by GCR information have to be compensated for. A reference mark is applied on the output image to indicate the starting point and order of the information sequence.

摘要翻译： 所公开的是在校准打印路径中进行数字水印的方法，包括：首先从输入图像接收具有颜色值的像素; 在输出图像中的相应像素处接收要编码的多个信息比特。 然后，选择至少两个不同的GCR功能中的一个，其中选择基于所接收的信息比特的状态。 要选择的GCR功能的数量取决于要在每个图像像素处被编码的信息比特的可能状态的数量，并且优选地等于要在每个图像像素处编码的信息比特的状态数，使得 GCR在输出图像之间空间变化。 此外，至少两个GCR功能被优化以携带信息，并且用标签表示旨在在输出图像内编码的信息位。 然后使用所选的GCR功能和颜色值生成CMYK值。 这些CMYK值被分配给输出图像中的相应像素。 在给定像素处要编码的信息位指示像素所属于的对象的类型，例如：图形，图片，文本，线条等。输出图像在打印时表现出基本相似的颜色出现的属性 在输入图像中的不同空间位置处，在打印中以基本不同的CMYK组合产生。 优选地，GCR函数使用参数化函数，编码状态设置函数的参数。 信息位应在整个输出图像中进行冗余编码。 不能由GCR信息编码的区域必须得到补偿。 在输出图像上应用参考标记来指示信息序列的起点和顺序。