【作者】 杨玲；

【导师】 邹建成； 李国富；

【作者基本信息】 北方工业大学 ， 应用数学， 2009， 硕士

【摘要】 目前,数字水印和信息隐藏技术已经形成了一定的理论基础,众多学者提出了大量的数字水印算法,于此同时,数字水印的容量问题成为一个令人关注的课题。水印的嵌入量、不可见性以及鲁棒性互相影响和制约。如何在达到一定嵌入容量的情况下,提高算法的鲁棒性,使水印能在各种攻击下,保持较高的检出率而又不影响原始图像的质量,是数字水印技术研究中遇到的主要问题。本文着力于研究信息隐藏及数字水印的容量问题,并将容量与数字水印算法结合起来。本文的主要结果有以下三个方面:1.提出了一种基于JPEG量化的容量自适应数字图像水印算法,从JPEG量化出发,对可嵌入水印的位置进行选择。在此基础上,结合人眼视觉模型和图像的纹理特性,得出水印最大可嵌强度,并给出相应的容量估计。实验结果表明,该算法能够同时满足压缩和水印嵌入的要求,不仅具有较好的不可见性和鲁棒性,而且在保证这些性能的基础上实现了自适应容量,较好地协调了水印三要素间的关系。2.提出了一种彩色图像多通道多水印算法,根据彩色图像的RGB三个通道,嵌入不同强度的三个水印,该算法可以抵抗裁剪,加噪,模糊,压缩等攻击。在保证水印不可见性的同时,多种水印相互配合,使得每个水印针对一些特定的处理方法有比较好的检测性能,从而实现了算法的全面鲁棒性。该算法容量大,鲁棒性强,相比单一水印算法具有较好的版权保护优势。3.提出了一种彩色图像盲水印算法,在亮度空间中嵌入水印,并结合图像的纹理特征,对纹理复杂度不同的分块选取不同的隐藏位置以嵌入不同强度的水印,同时把图像相关纹理特征信息记录下来作为提取密钥。该算法鲁棒性强,并可对图像的隐藏容量进行估计。更多还原

【Abstract】 At present, the digital watermarking and information hiding techniques have formed a theoretical basis, at the same time, a large number of digital watermarking algorithms had been proposed. The capacity of digital watermarking has become a major concern. The capacity, the invisibility, as well as the robustness of watermarking interact with one another. On condition of a certain capacity, it is the main point that how to improve the robustness of the watermarking, and maintain a higher detection rate without affecting the quality of the original image.This paper focuses on the capacity of information hiding and digital watermarking. There are three contributions in this thesis as follows:1. An algorithm of capacity adaptive digital image watermarking based on JPEG quantity was put forward. First, from the principle of JPEG quantity, the embedding positions could be selected. Then, the maximum watermark amplitude and watermark capacity were obtained by using the human vision system and image feature. At last, a simple amending polarity method was used to embed and extract the watermark. The simulation results show that this algorithm not only show good performance for embedding and compression requirements, but also have good invisibility and robustness. And this algorithm has realized the adaptive capacity. Thus, the relationship among the invisibility, robustness and capacity has been well balanced.2. Based on RGB color, a multi-channel image watermarking algorithm was proposed. The image could embed in three different watermarks, which were resilient to cropping, noising, bluring, compression and other attacks. Each watermark can afford specific attacks, so this algorithm has a more overall robustness. Compared to a single watermarking algorithm, this algorithm has larger capacity and robustness for copyright protection.3. A blind watermarking algorithm for color images was put forward, which used the brightness of the image to embed information. Combine with the texture characteristics of different images to select each sub-block’s hiding positions. Then put down the image texture features as a key for extraction. With good invisibility and robustness, this algorithm has realized the adaptive capacity.更多还原