共查询到19条相似文献，搜索用时 203 毫秒
1.
基于特征函数和质量因子的JPEG图像隐写分析 总被引：1，自引：0，他引：1
提出了一种新的JPEG通用隐写分析方法.通过分析JPEG图像DCT域和小波域的量化噪声模型和隐写模型,发现了量化噪声和嵌入噪声对图像的作用原理,并用直方图特征函数来区分2种噪声对图像的影响. 基于JPEG质量因子对图像进行分类,为每个图像分类单独训练支持向量机分类器.实验显示,本文方法相比已有的一些常用JPEG通用隐写分析方法具有更好的检测性能. 相似文献
2.
在利用失真测度来描述隐写引起的音频失真时,发现对同一原始音频进行多次直接 序列扩频隐写过程中,第一次隐写引起的失真最为剧烈．从直接扩频隐写的原理出发,提出了 从待检测音频提取相应失真测度作为特征向量,并利用支持向量机进行分类的隐写分析方法． 该方法不需要对原始音频进行估计．实验证明,本方法具有令人满意的性能,对不同嵌入强度 也同样有效,同时对嵌入容量的干扰提出２种改善策略． 相似文献
3.
基于信号和噪声的不同特征,提出一种阈值自适应选取的小波包降噪方法。该方法首先对信号进行小波包变换,利用噪声剩余率确定分解层数,采用对数能量熵选择最优基,然后采用阈值自适应选取的方法对高频系数进行分析。利用该方法进行降噪,不仅能够提高系统的信噪比,而且能够降低系统的重构误差。 相似文献
4.
5.
《黑龙江科技信息》2016,(24)
根据图像内容的最小化嵌入失真原则,在空域通用小波相对失真方法(Spatial-UNIversal WAvelet Relative Distortion,S-UNIWARD)的基础上,提出一种结合小波边缘检测和校验格编码(Syndrome Trellis Code,STC)的图像自适应空域隐写术。首先利用小波变换检测图像边缘区域,然后根据S-UNIWARD定义图像像素的嵌入失真,并通过设置失真阈值选择图像的纹理区域,最后使用STC在边缘区域和纹理区域对秘密信息进行嵌入。实验表明本算法提高了S-UNIWARD在图像边缘区域和纹理区域的嵌入精度,且能提高算法安全性。 相似文献
6.
7.
8.
文章采用了一种基于离散小波(DWT)多分辨率分解的数字水印技术,研究了水印算法,将图像进行三级小波分解,产生三个高频带系列子图和一个低频带子图。由于人眼对高频信息的敏感度低于对低频信息的敏感度,因此,采用了把水印嵌入到小波图像中的高频系数中。通过MATLAB仿真实验实现了将水印信息嵌入到原始图像中的技术,再对含水印图像加椒盐噪声、高斯低通滤波和缩小50%再放大200%进行攻击以及JPEG压缩实验仿真,结果表明所提算法具有很好的视觉效果和鲁棒性。 相似文献
9.
本文提出的弱小目标检测算法,首先利用小波包对图像进行多尺度分解,保证得到更适合于弱小目标信号的时频相平面。然后为了更好的消除噪声的干扰,给出了高斯判别准则,利用该准则对小波包树上的节点,自下而上地进行高斯性检验,并将相邻四个全高斯性小波包系数进行合并,得到图像的最优划分。 相似文献
10.
基于视觉感知模型的大容量视频隐写算法 总被引：2，自引：0，他引：2
为了获取较大隐写容量和较好不可感知性,结合人眼视觉感知特性,提出一种视觉感知指导数据嵌入的大容量视频隐写算法.该算法综合了多参数空间对比灵敏度函数、基于DCT(discrete cosine transform)块分类的纹理掩蔽效应及运动注意机制,以确定各DCT系数的失真掩蔽测度,进而控制隐写容量.实验结果表明,该隐写算法具有较大隐写容量,同时较好地保持了含密视频的不可感知性. 相似文献
11.
Xing He 《Journal of The Franklin Institute》2006,343(7):738-755
The perception of acoustic information by humans is based on the detailed temporal and spectral analysis provided by the auditory processing of the received signal. The incorporation of this process in psychoacoustical computational models has contributed significantly both in the development of highly efficient audio compression schemes as well as in effective audio watermarking methods. In this paper, we present an approach based on the discrete wavelet packet transform, which closely mimics the multi-resolution properties of the human ear and also includes simultaneous and temporal auditory masking. Experimental results show that the proposed technique offers better masking capabilities and it reduces the signal-to-masking ratio when compared to related approaches, without introducing audible distortion. Those results have implications that are important both for audio compression by permitting further bit rate reduction, and for watermarking by providing greater signal space for information hiding. 相似文献
12.
《Information processing & management》2022,59(2):102867
This paper proposes an algorithm that uses wavelet level adaptive decision-making for detecting high-voltage direct current (HVDC) discharge in wavelet transform cognitively. The identification and detection of HVDC discharge is an essential area of investigation, which contributes to ensuring pipeline safety and the optimal operation of an electrical power system. The proposed algorithm overcomes the wavelet packet transform’s disadvantage of needing to determine the level in advance. The decomposition level of wavelet packet transform is controlled by calculating relative wavelet energy change to decide its wavelet level. Our proposal extracts richer features of HVDC discharge by comparing other feature extraction algorithms. To select the best-suited mother wavelet function, we also design a selection method based on quantitative and qualitative approaches. An additional objective of this study is to detect the phenomenon of HVDC discharge using CP time-series data to assess the corrosion of energy pipelines. Moreover, a third primary discovery is that a wavelet-based application framework is designed to detect the HVDC discharge and further protect the energy pipeline. These discoveries can be valuably applied to the protection of power systems. They also provide brighter perspectives on future opportunities to expand on studies-to-date on the detection and classification of time-series data. 相似文献
13.
14.
通过Shannon熵算法采用自下向上的搜索方法选取最优小波包基,分别对原始图像和水印图像进行小波包分解,把水印数据嵌入选定的原始图像小波包基中。经攻击实验表明,应用本算法所实现的水印不可见,较好地保持了图像的质量,同时显示了较强的鲁棒性。 相似文献
15.
针对基于四象限压力传感器阵列的迎角测量方法中传感器信号受到干扰的问题,讨论了在其预处理中应用小波包变换进行信号分离提取的方法。根据小波包分解理论,对信号进行小波包分解,信号中频率不同的部分落在不同的尺度上,剔除反映干扰的变换尺度,提取出有用信息。结果表明,该方法可很好地提取信号的主要特征信息,也有效地去除了确定性干扰和随机噪声,与传统的信号滤波方法相比较具有明显的优点,同时为后续的信号处理奠定了基础。 相似文献
16.
This paper proves a general structural property of the wavelet tree for a given seminorm in the context of the wavelet packet transform method. This structural property can be used in denoising algorithms of different applications to guarantee the optimality of novel search strategies. The property holds for any input signals using any orthogonal analysing wavelet families. The property holds for any norms, which results to be a convex function through the wavelet tree. Using a defined norms, seminorms or pseudonorms, this property can be used to detect incoherent parts of an input signal by using the minimal depth of the tree. In this sense the proposed denoising procedure works without thresholds for the localisation of different kinds of noise, as well as for a stop criterium for an optimal representation of the incoherency. The proof of this property is performed by mathematical induction and the demonstration is based on orthonormality with the help of the multiresolution framework aspects of the wavelets packet tree. The Theorem is independent of the definition of the adopted norm and of the incoherent part of an input signal. In this sense, the discovered property is a general one, which is related to any norm and any nature of the signal incoherence. It can be used in different applications, in which a minimum of a norm is required to be calculated through the wavelet tree. 相似文献
17.
针对虹膜图像的纹理特征表示主要集中在中高频能量部分,对图像进行小波包分解,并提取出特征向量,运用变维方式对奇异值特征向量做进一步处理,进而将获得的特征向量做为虹膜图像的识别特征向量,依据欧氏距离分类器对他们做识别分类。最后的试验结果证明了这种算法的有效性与合理性。 相似文献
18.
重载的铁路货车滚动轴承极易出现损伤类故障,因故障的突发性使得振动信号具有非线性、非平稳的特性,且振动信号极易受非检测部位振动的干扰,而使得有效信号不易被提取,传统的基于傅里叶变换的检测方法无法有效将非平稳的振动信号中的干扰去除,造成最终的检测准确率不高的问题。为了提高检测准确率,提出基于小波包的检测方法,首先针对振动信号的非平稳特性采用小波滤波有效去除其中的干扰,然后通过最小二乘支持向量机提取出非平稳振动信号中的故障特征信号并完成故障检测。实验表明,这种方法能够有效去除振动信号中的干扰,并准确检测重载铁路货车上的滚动轴承损伤故障。 相似文献
19.
The bi-directionally coupled Lorenz systems are linked to the modeling of a coupled double loop thermosyphon system where the mass momentum and heat exchange are both considered. As the key parameters of the system, known as Rayleigh numbers, increase, the system of differential equations predicts typical flow dynamics in a thermosyphon from heat conduction to time-dependent chaos. In many applications including the thermosyphon systems, there are uncertainties associated with mathematical models such as unmodeled dynamics and parameter variations. Also, under the high heat environment for a thermosyphon, there exist external disturbances quantitatively linked to the Rayleigh numbers. All these sources constitute uncertainties to the dynamical system. Our objective is to design adaptive controllers to stabilize the chaotic flow in each thermosyphon loop with unknown system parameters and existence of uncertainties. The controllers consist of a proportional controller with an adaptive gain and a wavelet network that reconstructs the unknown functions representing the uncertainties. Explicit stability bounds and adaptive laws for the control parameters are obtained so that the coupled Lorenz systems are globally stabilized. 相似文献