A method of embedding a gray-level digital watermark into an image is proposed in this paper. By stack filter's threshold decomposition technique, a gray-level digital watermark is decomposed into a series of binary digital images for implementing multiple watermarking. Experimental results show that the proposed techniques are successfully tolerant to reasonable image processing operations and the lossy compression techniques such as Joint Photographic Experts Group (JPEG) compression techniques.

本文提出了一种具有几何变换撸棒性的动态图像水印技术。一个沿时间轴上的模板嵌入到动态图像序列中的每个水印最小段（Watermark Minimum Segment）内。利用预先嵌入的时间轴模板，可以恢复受几何仿射（affine）变换攻击后的含水印动态图像帧，仿真试验结果表明本文提出的动态图像水印技术，经仿射（affine）变换攻击后仍是撸棒的。

本文提出一种将彩色数字水印镶嵌到原始图像中的方法。利用静态图像的压缩编码技术，将彩色数字水印编码为一系列二值ID 数字，以实现水印的镶嵌。由于水印的嵌入过程是基于原始图像的数字余玄变换（DCT）系数之间的关系，所以水印的提取不需要原始图像。实验结果表明本文提出的数字水印技术，经一些图像处理操作和有损压缩后仍是健壮的。

Digital watermarking has been presented in recent literatures as a technique to protect the copyright of multimedia data. But most of these literatures focus on the algorithms of embedding one-dimensional watermarks or two-dimensional binary digital watermarks. In this paper, a method of embedding a gray-level digital watermark into an image is proposed. By stack filter's threshold decomposition technique, a gray-level digital watermark is decompounded into a series of binary digital images for implementing multiple watermarking. The experimental results show that the proposed techniques are successfully tolerant to reasonable image processing operations and the lossy compression techniques such as Joint Photographic Experts Group (JPEG).

A video watermarking technique based on discrete fractional Fourier transform (DFRFT) is proposed. Each frame of original video is first decomposed into two-dimensional (2-D) multiresolution representations by 2-D discrete wavelet transforms (DWT) along the spatial axis. Then the wavelet coefficient frames in each group of pictures (GOP, each is 16 frames) are transformed into DFRFT coefficient frames by one-dimensional (1-D) DFRFT along the temporal axis. The watermark is embedded into each DFRFT coefficient frame in the GOP, and the angular parameter of the DFRFT can be changed to adapt itself to the original video. Experimental results show that the proposed technique is robust enough against the attacks of frame dropping, averaging and lossy compression.