提出一种利用图像边缘和Directionlet变换构造水印同步信息的新水印算法。将图像一条显著边缘的方向作为Directionlet的变换方向，与之成特定角度的方向作为队列方向，据此生成整数栅格的采样矩阵；水印在每个陪集的中低频子带内自适应嵌入；以图像显著边缘为一坐标轴建立坐标系，在该坐标系内检测水印，可以排除几何攻击对水印位置的影响。实验结果表明,较之基于Wavelet和Contourlet的水印算法，本文方法对抗几何攻击的优势非常突出，尤其对旋转攻击，效果更明显。

A novel watermarking method to construct watermark synchronism by using image specific edge and Directionlet transform was proposed. The direction of the image specific edge is selected as the transform direction of Directionlet, the alignment direction of Directionlet is achieved by forming an invariable angle with the transform direction. The generator matrix of the lattice is given by the two direction vectors.Several copies of watermark are adaptively inserted into coefficients of the selected middle and low frequency subband of all the cost of the lattice. In order to eliminate the effect of geometric attacks，the watermark is detected in the reference frame established by utilizing the direction of the image specific edge as direction of its an coordinate axis. Experimental results show the proposed watermarking algorithm outperforms the Wavelet and Contourlet-based in terms of transparency as well as robustness,especially at the geometric attacks such as rotation.