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针对印刷品的特点,本文研究了一种基于数字水印技术的防伪认证方法.方法在载体图像的DCT域中嵌入条码水印,使水印具有一次印刷鲁棒,二次非法复制印刷脆弱的特性,并使用拍照的手段对印刷品进行快速采集检测.经实验测试,方法能够较准确的提取认证水印信息来判断印刷品的真伪. 相似文献
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QR Code二维条码在纸币防伪技术中应用 总被引:2,自引:0,他引:2
纸币的防伪是世界各国金融系统都面临的十分重要又棘手的问题,笔者在保留了纸币原有防伪功能的基础上,提出了一种将数字化的QR Code二维码与数字水印技术相结合的新型的数字化防伪技术。利用RSA加密算法对纸币代码进行加密,并生成二维码。最后利用DWT域水印算法嵌入和提取水印图像。仿真实验结果证明了该技术的有效性。 相似文献
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快速响应码图像的全方位识别 总被引:4,自引:1,他引:4
首先分析快速响应码位置探测图形的模式,提出一种基于一维特征模板匹配的快速定位方法,并实现图像方位归一化,然后对条码边界进行Hough变换得到边界直线和顶点位置,再利用条码的几何特征做控制点变换和双线性插值变换,进行几何失真校正和大小归一,形成只包含条码的图像,最后采用Sobel边缘检测以及傅里叶反模糊滤波方法识别条码模块,得到可以解码的比特流信息,实验表明这些算法有效消除了图像中无关信息干扰和几何失真对识别的影响,实现了条码图像的全方位快速识别。 相似文献
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本文主要讨论在小波域嵌入数字水印的研究。在低频区域嵌入水印,其稳定性好,但容易被人眼察觉;高频域嵌入水印不易被察觉,但稳定性差、易遭到恶意攻击。本文选择在低频和高频区分别嵌入水印,并选择不同的嵌入强度。水印图像选择具有特殊意义的二值图像‘吉林大学’水印,用Matlab7.6.0(R2008)仿真。实验表明,本算法对压缩、滤波、噪声攻击有很强的鲁棒。 相似文献
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针对当前日益严重的数字多媒体作品侵权问题,基于最新版权保护的数字水印技术,提出了一种基于图像特征的盲水印算法。首先利用原始图像的边缘特征确定了分块对应的水印强度因子;然后通过在分块Hadamard变换域中修改中频系数来嵌入水印。实验结果表明,盲水印算法对常用的图像处理(如JPEG压缩、加噪、剪切和滤波等)攻击具有较好的鲁棒性,在数字作品的版权保护领域具有一定的应用价值。 相似文献
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加密同轴全息数字水印 总被引:4,自引:0,他引:4
在研究数字全息技术的基础上,提出了一种新的加密的同轴全息数字水印方法。该方法包括加密和解密两个过程。加密过程首先将原始二值水印图像经过输入面和频谱面上分别放置随机相位模板进行调制加密,生成加密的复数图像,将其作为物光信息,再与参考光信息叠加生成同轴全息图像,然后将其作为水印嵌入到载体图像中;解密过程是加密过程的逆过程,水印重建不需要原始图像的参与,属盲检测过程。在理论分析部分证明了该水印技术的有效性,在仿真实验部分证明了该水印技术具有抗随机噪声干扰、剪切干扰、有损压缩和低通滤波等常见的干扰能力。文中还详细研究了全息数字水印的嵌入强度及对应恢复水印的效果。 相似文献
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《Measurement》2016
Many image tamper detection methods implement authentication and recovery in units of blocks; however, these methods do not consider the characteristics of blocks to distinguish watermark embedding and detection modes, thus resulting in poor hiding effects. We suggest that embedding an excessive number of bits within a region with only a slight change in an image to record recovery information is unnecessary. In addition, more recovery information is required in a region with major changes to improve recovery quality. Therefore, this study used smoothness to distinguish the types of image blocks, and employ different watermark embedding, tamper detection, and recovery strategies for different block types to enhance hiding efficiency, authentication, and recovery effects. The experimental results regarding the authentication error rate and image quality showed that the proposed scheme has satisfactory performance. 相似文献
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A robust digital watermarking scheme for video copyright protection in the wavelet domain 总被引:3,自引:0,他引:3
This paper proposes a novel digital watermarking method for video based on a multi-resolution wavelet decomposition. The watermark used is a binary image. This watermark is embedded in the wavelet coefficients of the LH, HL and HH sub-bands of the second wavelet decomposition level by quantization. Every bit of the watermark is spread over a number of wavelet coefficients with the use of a key. The resulting watermarking scheme can be used for public watermarking applications, where the original image is not available for watermark extraction. We have tested the resilience of the watermarking algorithm against a series nine different attacks for different videos and improved the decoding BER by redundant embedding of the same watermark in different frames and by using an error correction code. Experimental results show that the embedded watermark is invisible and robust to attacks. 相似文献
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This paper proposes a novel image authentication scheme in the wavelet domain. The scheme uses a semi-fragile watermark to detect and precisely locate malicious tampering in images. The wavelet coefficients selected for embedding are randomly permuted with a secret key, achieving high security. A bit of the watermark is embedded in a group of coefficients by means of quantization. The experimental results show, that our algorithm achieves high image quality and high tampering detection resolution at a low watermark payload, compared to block-based authentication schemes. Thanks to the random permutation, the watermark is protected against local attacks. We have also conducted experiments to demonstrate the robustness of the watermark against mild to moderate JPEG compression. 相似文献
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防止CAD作业拷贝方法的研究 总被引:1,自引:0,他引:1
为防止学生在计算机绘图实验中拷贝作业,借鉴水印嵌入方法,研究了AutoCAD图形文件拷贝的检测方法。把学生操作计算机的IP或MAC地址作为水印信息嵌入至学生作业文件中,检测时提取图形的水印信息,以检测作业是否拷贝而来。经教学实践检验,能较准确判断作业是否拷贝抄袭,显著提高了计算机绘图的教学效果。 相似文献