Optical watermarking technique robust to geometrical distortion in image
Optical watermarking technique robust to geometrical distortion in image
复制标题
对图像几何失真具有鲁棒性的光学水印技术
DOI：
10.1109/isspit.2010.5711727
复制
发表时间：
2010
期刊：
影响因子：
--
通讯作者：
K. Yanaka
中科院分区：
文献类型：
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作者：
Y. Ishikawa;K. Uehira;K. Yanaka
本文提出了一种利用空间调制照明的光学水印技术，它对图像中的几何失真具有鲁棒性。它可以保护“模拟”对象，如艺术家画的画，使其在博物馆中不被非法拍照。在实际情况下，非法捕获的图像可能包含各种失真，并且嵌入的水印可能被错误地检测。由拍摄物体的拍摄角度引起的几何失真是一个特别主要的问题。我们进行了实验，以评估的鲁棒性的水印图像的几何失真，其中失真是故意通过移动的投影仪和数码相机的位置，从前面的对象。当使用离散余弦变换（DCT）和沃尔什-哈达玛变换（WHT）作为嵌入水印的方法时，即使投影仪和数码相机之间的拍摄角度倾斜约20度，提取的水印数据的准确度也几乎为100%。我们引入了矩形网格拟合和基于四个最近点的“双线性插值”技术来校正失真。
This paper presents an optical watermarking technique that is robust against geometrical distortion in images by using spatially modulated illumination. It can protect “analog” objects like pictures painted by artists from having photographs taken of them illegally in museums. Illegally captured images in practical situations may contain various distortions, and embedded watermarks may be incorrectly detected. Geometrical distortion caused by the shooting angle that the objects are captured at is a particularly major problem. We carried out experiments to evaluate the robustness of watermarking images that were geometrically distorted, in which distortions were intentionally created by moving the position of the projector and the digital camera from right in front of the object. The accuracy of the extracted watermarking data was almost 100%, even if the shooting angle was inclined by about 20 degrees between the projector and digital camera, in both cases when a Discrete Cosine Transform (DCT) and a Walsh-Hadamard Transform (WHT) were used as the methods of embedding watermarks. We introduced rectangular mesh fitting and a technique of “bi-linear interpolation” based on the four nearest points to correct the distortions.