共查询到19条相似文献，搜索用时 140 毫秒
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一种基于二维离散小波变换的视频水印嵌入和盲提取算法 总被引：1，自引：0，他引：1
视频数字水印技术是当前水印研究中的一个热点。本文提出一种视频数字水印新算法,算法首先使用混沌序列对待嵌入水印信号进行混沌调制,然后对视频数据流中每帧图像进行2D-DWT后的低频小波系数进行操作,根据奇偶量化的特性,将水印信息嵌入到小波变换后的视频流中。所提出的水印算法简单、有效,实现了水印的盲提取,与嵌入水印前的原视频图像相比,嵌入水印后的视频图像信噪比损失很小。 相似文献
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针对传统三维数字图像嵌入水印算法保留的水印特征信息过多,易被攻击的弊端,提出了一种考虑水印特征隐藏的三维数字图像保护方法,对于待加入水印的三维数字图像,引入分块DCT算法对原始图像进行水印特征隐藏处理并得到水印特征隐藏图元矩阵,再将水印图像通过BCH编码进行特征隐藏降噪压缩。根据设定的特征隐藏系数随机分配图元位置并插入原始图像中,得到包含特征隐藏水印的数据图像。仿真结果表明,该方法嵌入的特征隐藏水印不仅可抵抗多种不同类型攻击,比传统算法抗噪声攻击性提高了约25%,抗剪切攻击性提高了15%左右。 相似文献
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在本文中,结合Amold变换,提出了一种基于图像置乱变换和DCT中频的数字水印算法。首先对被隐藏图像进行Amold置乱,再利用算法把待隐藏信息嵌入到载体图像的中频系数。算法研究结果表明水印具有较好的不可见性及健壮性。对嵌入水印后的图像进行了攻击实验,实验表明该算法对于JPEG压缩具有较好的鲁棒性。 相似文献
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本文简要介绍了视频水印技术和DCT的概念,以MatLab为平台,结合视频水印技术,提出了一种新的面向MPEG-4未压缩域的DCT变换域水印算法。实验证明该算法具有良好的鲁棒性、不可见性,且水印嵌入量较大。 相似文献
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水印技术是保障图像安全的一项重要技术,为了克服当前图像水印算法存在水印信息嵌入量小、抗攻击鲁棒性差的缺陷,设计了基于压缩感知理论的图像水印算法。首先采用小波变换对原始图像进行预处理,分解为不同频率的子图像,并采用压缩感知算法对高频子图像进行压缩处理,提高图像传输效率;然后采用混沌系统对水印信息进行处理,产生水印序列,并将水印序列嵌入到低频子图像中,最后采用小波变换对嵌入水印的低频子图像和压缩后的高频子图像进行融合,得到嵌放水印的载体图像,并可以采用压缩感知理论的重构算法提取水印信息。与数字图像水印算法进行了对比测试,结果明,本文算法大幅度改善了水印信息的嵌入量,嵌入水印合的载体具有良好的透明性,而且对各种攻击具有较好的鲁棒性,具有十分显著的优势。 相似文献
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Anubha Gupta Shiv Dutt Joshi Pushpendra Singh 《Journal of The Franklin Institute》2018,355(17):8989-9016
This paper establishes connection between discrete cosine transform (DCT) and the discrete-time fractional Brownian motion process (dfBm). It is proved that the eigenvectors of the auto-covariance matrix of a dfBm can be approximated by DCT basis vectors in the asymptotic sense. This shows that DCT basis acts as discrete Karhunen–Loève transform (DKLT) for these processes in the approximate sense. Analytic perturbation theory of linear operators is used to prove this result. This result will be of great practical significance in applications where one is looking for an appropriate basis to work with signals that can perhaps be modeled as belonging to fBm processes. The utility of the proposed work has been illustrated with two real-life data (a) on compressive sampling based reconstruction of financial time-series and (b) in denoising gravitational wave event GW150914 data obtained from a binary black hole merger. 相似文献
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Samir Abd Elghafar Salaheldin M. Diab Bassiouny M. Sallam Emad S. Hassan Mona Shokair Waleed Al-Nauimy Moawad I. Dessouky El-Sayed M. El-Rabaie Saleh Alshebeili Fathi E. Abd El-Samie 《Journal of The Franklin Institute》2014
This paper presents a new implementation of discrete multi-tone (DMT) systems based on different discrete transforms that include the discrete sine transform (DST), discrete cosine transform (DCT), and discrete wavelet transform (DWT). The implementation also considers time-domain equalization to mitigate channel distortion. Compared to the fast Fourier transform discrete multi-tone (FFT-DMT) system, the proposed implementations have an advantage in that their energy-compaction property helps in reducing the channel effects. The performance of the DST-DMT, DCT-DMT, DWT-DMT, and FFT-DMT systems, employing a time-domain equalizer (TEQ), is investigated in the paper. It has been demonstrated by computer simulations that the proposed implementations outperform the FFT-DMT system and that the utilization of the TEQ can lead to higher bit rates 相似文献
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This paper presents a novel dynamic stochastic resonance (DSR)-based technique for robust extraction of a grayscale logo from a tampered watermarked image. The watermark embedding is done on the singular values (SV) of the discrete cosine transform (DCT) coefficients of the cover image. DSR is then strategically applied during the logo extraction process where the SV of DCT coefficients are tuned following a double-well potential model by utilizing the noise introduced during attacks. The resilience of this technique has been tested in the presence of various noises, geometrical distortions, enhancement, compression, filtering and watermarking attacks. The proposed DSR-based technique for logo extraction gives noteworthy robustness without any significant trade-off in perceptual transparency of the watermarked image. A maximization approach has been adopted for the selection of bistable double-well parameters to establish noise-enhanced resonance. When compared with existing watermark extraction techniques based in SVD, DCT, SVD-DCT domains, as well as with their combination with DSR, the results suggest that remarkable improvement of robustness is achieved by using DSR on singular values of DCT. 相似文献
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离散余弦变换(DCT)是一种映射变换方法,通过把图像中的各个像素从一种空间变换到另一种空间,达到图像压缩的目的。本文对基于DCT变换的图像压缩方法进行了研究,给出了基于DCT变换的图像压缩的基本原理及其实现步骤,并最终给出了图像压缩结果。 相似文献
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This paper proposes an online video-based approach to handwritten Arabic alphabet recognition. Various temporal and spatial feature extraction techniques are introduced. The motion information of the hand movement is projected onto two static accumulated difference images according to the motion directionality. The temporal analysis is followed by two-dimensional discrete cosine transform and Zonal coding or Radon transformation and low pass filtering. The resulting feature vectors are time-independent thus can be classified by a simple classification technique such as K Nearest Neighbor (KNN). The solution is further enhanced by introducing the notion of superclasses where similar classes are grouped together for the purpose of multiresolutional classification. Experimental results indicate an impressive 99% recognition rate on user-dependant mode. To validate the proposed technique, we have conducted a series of experiments using Hidden Markov models (HMM), which is the classical way of classifying data with temporal dependencies. Experimental results revealed that the proposed feature extraction scheme combined with simple KNN yields superior results to those obtained by the classical HMM-based scheme. 相似文献
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In this paper, an algorithm is developed to apply Hann, Hamming, Blackman and related windows directly in the transform domain for the discrete cosine transform and discrete sine transform. These algorithms are useful in applications where windowing is required in order to minimize edge effects caused by implicit symmetries in the transform domain that are not replicated in the real-world data. Examples of such applications include data communication, adaptive system identification and filtering, real-time analysis of financial market data, etc. Software implementations in C language are also given. 相似文献
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Rui-Bing Li Ben Niu Zhi-Guang Feng Jun-Qing Li Pei-Yong Duan Dong Yang 《Journal of The Franklin Institute》2019,356(16):9545-9564
This paper dedicates to dealing with the adaptive neural design problem for uncertain stochastic nonlinear systems with non-lower triangular pure-feedback form and input constraint. On the basis of the mean-value theorem, the pure-feedback structure is first transformed into the desired affine structure, and then the well-known backstepping technology is applied to construct the actual input signal of the controller. Although the considered system has a fairly complex structure, a new adaptive neural tracking controller design frame is established via the flexible application of radial basis function (RBF) neural networks’ (NNs’) structural characteristics. The proposed design frame guarantees the control objective of this paper can be achieved. Finally, a simulation example is given to further illustrate the availability of the proposed control scheme. 相似文献