共查询到20条相似文献,搜索用时 62 毫秒
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目前QR二维码采用隐形印刷等材料防伪加密比较复杂,只能在证件上使用,现有的数字水印加密技术在用于二维码加密时,没有很好的结合QR二维码自身的编码规则,负载的加密信息较见根据QR二维码的信息存放位置特点和QR二维码图像特征,将水印位置和链码相结合,设计了一种新的二维码水印加密和其解密算法。另外可以结合人体的多重生物特征对QR二维码进行加密,水印位置有限时采用模拟退火算法解决各项特征之间的位置竞争问题。理论和实验表明,该算法具有速度快,准确率高,加密不影响二维码基本信息的识别,加密后的二维码图片能够被主流的QR码识别工具识别。 相似文献
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为了确保上传到“云”端环境下的数字产品的隐蔽性和安全性,在逐渐向“云”端转移的快速响应(Quick Response, QR)码的理论基础上研究并提出了一种QR码双重加密复合数字水印算法,防止QR码“云”端丢失的可能性。对“云”水印图像进行QR码编码生成QR码水印图像,确保水印信息的安全性,再对QR码水印信息实施加密置乱;对“云”上载体Lena图像进行非下采样轮廓波变换(Non-subsampled Contourlet Transform, NSCT),选择储存信息更多的低频部分进行离散小波变换(Discrete Wavelet Transform, DWT),对图像抵抗力较强的低频图像进行奇异值分解(Singular Value Decomposition, SVD),在分解的奇异值中加权加密的QR码水印。通过对算法进行实验验证,该算法在视觉效果较好的前提下,考虑实用性,将复合算法和加密相结合,提高了算法的抵抗力,尤其是旋转攻击和JPEG压缩攻击。 相似文献
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随着数字化时代的到来,防止数据和信息的泄露问题是现如今持久关注的问题。在视觉密码加密过程中,人们侧重于原始秘密信息的保护,而忽视了对共享份保护以及信息传输过程中发送者与参与者的验证。因此,本文在(k,n)像素不扩展的视觉密码方案下,基于QR码的纠错容错功能,对现存的隐藏方法进行改进,提出了一种保护秘密共享份的安全分享方案。针对QR码在重要信息的传输时,易被窃取者任意读取篡改这一现实问题,利用RSA非对称加密算法对QR码的发送传输进行验证保护。实验结果表明,本文方案减少了共享份在加密和发送过程中受到的攻击性,实现了对发送者和参与者的验证,保证了QR码编码内容的真实性和传播过程中的可靠性。 相似文献
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随着移动终端和移动互联网的发展,快速响应(QR)码被广泛运用于移动信息交互。但是,标准的 QR 码是由均匀分布的黑色与白色模块组成,外观类似噪声信号,缺乏视觉美感,限制了QR码的应用。针对此问题,该文提出一种提高QR码视觉效果的美化方法。该方法将给定的彩色图像进行显著性检测和半色调处理,得到相应的显著性矩阵和半色调图像,然后根据半色调图像上的网点分布,对QR码的模块分布进行优化。为了提高优化效率,该文提出一种显著性加权随机优化算法,将优化后的QR码和半色调图像进行融合,得到与半色调图像最相似的半色调QR码。在图像渲染阶段,该文提出一种基于二分搜索的色彩调整算法,得到具有色彩信息和视觉美感的彩色QR码。实验分析表明,该方法生成的QR码不仅保留了与标准QR码一样的抗遮挡、快速解码等特性,还有效地提升了视觉效果,具有很好的视觉吸引力。 相似文献
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The article describes a model representation of radar probing data in form of a mixture of background and target samples, which is the sum of two random variables with very different parameters. For model development we research the behavior of the central moments of the distribution mix without assuming the distribution law form. An example it is described the detection of the signal at the output of compression system of chirp ionosonde. 相似文献
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解决IP网QoS问题是目前通信领域的研究热点之一.虽然研究已经取得了一定的进展,但人们对于IP 网QoS本身的含义及相关的问题还有着不同的理解.本文将从IP网QoS的定义入手讨论相关的一些问题以及解决IP网QoS问题所做的各种努力. 相似文献
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《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1968,56(6):1024-1032
Assuming that visual responses are due to the action of particles on the membrane of the visual cells, the stochastic variability of the response should be a function of the number of particles producing it. Quantitative predictions can be made with the aid of a model proposed in previous articles. It is found that responses produced in visual cells of Limulus by absorption of a single photon have the stochastic properties which would be expected if the response to one photon were brought about by 25 particles. It is concluded from this that the processes leading to visual responses produce multiplication of particles. The effects of temperature and of metabolic poisons suggest that these processes are of chemical nature. 相似文献
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By means of exact conformal mapping method we have defined character of dependence of squares amounts of angular part of film
element on angled part dimension. We propose relations, approximating obtained dependence. Calculation results and experimental
researches of large-scale models are represented. 相似文献
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Moshrefzadeh R.S. Radcliffe M.D. Lee T.C. Mohapatra S.K. 《Lightwave Technology, Journal of》1992,10(4):420-425
The temperature dependence of refractive index of polymer films was determined for a number of slab waveguides by a grating coupling method. This dependence was examined as a function of parameters such as molecular weight and glass transition temperature of the polymer. Temperature-induced changes in N TE-N TM , N being the effective index, were studied systematically for different slab waveguide compositions. It is shown that with proper device design and choice of polymeric materials, thermal effects can be reduced 相似文献
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A. M. Emel’yanov 《Semiconductors》2010,44(9):1134-1139
A method for analyzing the luminescence spectra of semiconductors is suggested. The method is based on differentiation of
the spectra. The potentialities of the method are demonstrated for luminescence in the region of the fundamental absorption
edge of Si and SiGe alloy single crystals. The method is superior in accuracy to previously known luminescence methods of
determining the band gap of indirect-gap semiconductors and practically insensitive to different conditions of outputting
radiation from the sample. 相似文献
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“计算机组成原理”设计性实践教学模式研究 总被引:1,自引:0,他引:1
本文阐述了"计算机组成原理"设计性实验教学的重要性,对设计性实验教学的目的和基本特征进行了归纳,对"计算机组成原理"设计性实验教学的现状进行了调查,对存在的问题进行了较深入的分析;在此基础上.对组成原理设计性实验的教学模式进行了研究,对设计性实验的体系进行了初步设计,并对"计算机组成原理"设计性实验的实施方法进行了探讨. 相似文献