基于B样条多分辨率表示的一种数字水印方法

本文根据B样条多分辨率表示的特点提出了一种盲数字水印方法，把原图像做二次小波分解，在低频子图像上用Harris特征点检测算法选取特征点，在以特征点为圆心的同心圆上选点的灰度值作为控制顶点建立B样条曲线，对B样条曲线做多分辨率分解，在低分辨率系数中嵌入水印。由于小波分解后选特征点以及Harris特征点具有几何变换不变性，试验表明该方法对JPEG压缩、缩放、旋转、平移、剪切、滤波等具有较强的抵抗力。

A Watermarking Scheme Based On B-spline Multiresolution Representation

A blind digital image watermarking scheme is presented according to the characteristics of B-spline muhiresolution representation in this paper.A discrete wavelet transform is made to an image,and feature points are detected in the low-resolution sub-image with Harris detector,then a group of uniform B-spline curvesare defined with gray values of the points on the homocentric circles centered at each selected feature points as control points,finally these B-spline curves are decomposed and the bits of watermark signal are embedded in the low-resolution coefficients.Because of detecting feature points after wavelet transform and the invariant property against geometric transformation of Harris feature points,experimental results show that our scheme is robust in withstanding common attacks such as JPEG compression,scaling,rotation,translating,cropping and so on.