公开(公告)号：US20050041832A1

公开(公告)日：2005-02-24

申请号：US10644342

申请日：2003-08-20

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

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

IPC分类号： G06T1/00 ,  G06K9/00 ,  G06K9/34 ,  H04N1/32 ,  H04N1/387 ,  H04N1/40 ,  H04N1/46 ,  H04N1/60

CPC分类号： G06K9/36 ,  H04N1/32309 ,  H04N1/32352

摘要： What is disclosed is a decoding method for retrieving information bits encoded in a printed image comprising the steps of first receiving an input electronic image as a scanned version of the printed image. A region of interest in the image is then extracted and, for that region, an amount of K colorant present, denoted KH; is obtained. Further, a color value is generated therefrom and the GCR used for encoding that region is determined using KH and the obtained color value. Encoded information bits are retrieved therefrom based on the determined GCR. The estimated KH is preferably evaluated conditional to a capacity signal KL and a luminance signal L. From the obtained data, values of KH, KL, and L, are derived wherein KH is estimated from a high resolution scan, and KL and L are estimated from a down-scaled image, respectively. The capacity signal KL and the luminance signal L are derived from the obtained color value. Further, the capacity signal, KL is derived by first applying a suitable operator S to reduce the image from scanner resolution to the watermark resolution and then converting the obtained color values to CMY estimates such that KL=min(C,M,Y) Alternatively, K-capacity is derived from the amount, KL, y, comprises first converting the obtained color values to CMY estimates and applying a suitable operator S to reduce the image from scanner resolution to the watermark resolution such that KL=min(S(C),S(M),S(Y)); wherein L is described by a linear combination of scan signals RGB, such that L=k1S(R)+k2S(G)+k3S(B). The value of KH is determined by first converting the obtained color values to CMY estimates. The estimates determine K-colorant amount at each pixel such that: K=min(C,M,Y). A suitable operator S is applied to reduce the image from scanner resolution to the watermark resolution.

摘要翻译： 所公开的是一种用于检索印刷图像中编码的信息位的解码方法，包括以下步骤：首先接收作为打印图像的扫描版本的输入电子图像。 然后提取图像中的感兴趣区域，并且对于该区域，表示为KH的存在的K个着色剂的量; 获得。 此外，由此生成颜色值，并且使用KH确定用于编码该区域的GCR和所获得的颜色值。 基于确定的GCR从其中检索编码信息比特。 优选地，估计的KH被评估为对容量信号KL和亮度信号L的条件。从所获得的数据导出KH，KL和L的值，其中从高分辨率扫描估计KH，并且估计KL和L 分别从缩小图像。 从获得的颜色值导出容量信号KL和亮度信号L. 此外，通过首先应用合适的运算符S将图像从扫描仪分辨率减小到水印分辨率，然后将所获得的颜色值转换为CMY估计，使得KL = min（C，M，Y），得到容量信号KL K的容量是从数量导出的，KL，y包括首先将获得的颜色值转换为CMY估计，并应用合适的算子S将图像从扫描仪分辨率减小到水印分辨率，使得KL = min（S（C ），S（M），S（Y））; 其中L由扫描信号RGB的线性组合描述，使得L = k1S（R）+ k2S（G）+ k3S（B）。 首先将获得的颜色值转换为CMY估计值来确定KH的值。 估计确定每个像素处的K-着色剂量，使得：K = min（C，M，Y）。 应用合适的算子S将图像从扫描仪分辨率减小到水印分辨率。