共查询到20条相似文献,搜索用时 0 毫秒
1.
基于心理声学模型和临界频带子波变换的数字声频水印 总被引:11,自引:0,他引:11
提出了一种基于临界频带子波变换的声频数字水印算法。首先根据心理声学模型,计算载体声频信号的掩蔽阈值,利用人耳听觉的临界频率与临界频带子波变换域的相似性,将掩蔽门限映射到临界频带子波域,然后将水印信号嵌入到中低频子波系数中,嵌入强度由掩蔽阂值自适应控制。实验结果表明:该算法隐藏水印具有很强的掩蔽性,对原始语音的影响基本上察觉不出来;叠加了水印的声频信号对数据压缩、加噪、重采样、低通滤波等常用声频信号处理技术具有很好的鲁棒性。 相似文献
2.
3.
A novel multiple color-image fusion and watermarking using optical interference and wavelet transform is proposed. In this method, each secret color image is encoded into three phase-only masks (POMs). One POM is constructed as user identity key and the other two POMs are generated as user identity key modulated by corresponding secret color image in gyrator transform domain without using any time-consuming iterative computations or post-processing of the POMs to remove inherent silhouette problem. The R, G, and B channels of different user identity keys POM are then individually multiplied to get three multiplex POMs, which are exploited as encrypted images. Similarly the R, G, and B channels of other two POMs are independently multiplied to obtain two sets of three multiplex POMs. The encrypted images are fused with gray-level cover image to produce the final encrypted image as watermarked image. The secret color images are shielded by encrypted images (which have no information about secret images) as well as cover image (which reveals no information about encrypted images). These two remarkable features of the proposed system drastically reduce the probability of the encrypted images to be searched and attacked. Each individual user has an identity key and two phase-only keys as three decryption keys besides transformation angles regarded as additional keys. Theoretical analysis and numerical simulation results validate the feasibility of the proposed method. 相似文献
4.
提升小波变换和混沌加密的数字声频水印 总被引:1,自引:1,他引:0
提出了一种提升小波变换和混沌加密的数字声频水印算法。先对声频信号进行提升小波变换,通过修改提升小波变换系数的统计平均值来实现同步码和水印信息的嵌入,利用听觉掩蔽阈值来自适应确定最佳嵌入强度,以保证嵌入隐藏信息对人耳的不可感知性;为了改善水印的安全性,采用改进logistic混沌映射产生密钥序列对隐藏信息进行加密。实验结果表明:与传统的傅里叶变换、余弦变换、小波变换的声频水印方案相比,本文方法具有更好的不可感知性和安全性,且能够更加有效地抵抗各种常见信号处理攻击。 相似文献
5.
6.
7.
一种基于小波变换的跨带矢量量化 总被引:1,自引:0,他引:1
由小波变换产生的子带之间存在着较强的相关性,然而目前的在基于小波变换的图像编码矢量量化中,码矢往往仅由带内系数组成,没有充分利用带间相关性。本文提出一种新的跨带矢量量化算法,码矢由在同级子带中的相应系数组成。在三次小波变换下,第一级子带的码矢维数为48D,第二级为12D,第三级为3D。这样形成的码矢既匹配了各级子带的重要性,又利用到了带内和带间相关性,在相同的比特率下,其重构图像的信噪比PSNR比码矢仅由带内系数组成的传统带内VQ高出1~2dB。 相似文献
8.
D. A. Andreev S. V. Bozhokin I. D. Venevtsev K. T. Zhunusov 《Technical Physics》2014,59(10):1428-1433
A model of a pulsed signal in the form of a superposition of elementary nonstationary signals is considered. The parameters of such a superposition are chosen so that signal amplitude A(t) strongly varies with time. For such a signal, the analytic expression for the Gabor transform (GT) and continuous wavelet transform (CWT) using the mother Morlet wavelet are analyzed. A criterion is proposed for the matched behaviors of GT and CWT with signal amplitude A(t). The advantages of the CWT adaptively selecting the window size over the GT whose explicit form depends on the window size are demonstrated. The proposed method can be used for analysis of many transient stages of time-dependent signals in various branches of physics. 相似文献
9.
为实现图像水印在数据认证、访问控制和版权保护等领域发挥作用,提出一种人眼视觉感知特性的小波变换数字图像水印算法。首先对二值图像水印进行Arnold变换,并采用行堆叠的方法,转换成一维序列,然后根据密钥生成的高斯序列中值的正负来确定水印信息嵌入时是采用那种调制方式,最后对原始图像进行3级DWT分解,在小波图像的第二层中频子带中,结合人眼视觉特性将水印正向或负向调制叠加在宿主图像大于JND 值的小波系数上。实验结果表明:该算法能抵抗JPEG压缩、加噪、剪切等多种攻击,具有良好的透明性,鲁棒性和安全性。 相似文献
10.
Blind image watermarking based on discrete fractional random transform and subsampling 总被引:1,自引:0,他引:1
This paper proposes a blind watermarking scheme based on discrete fractional random transform. The watermark information can be a binary sequence, a gray level image or a set of decimal fractions sampled from a given source signal. The host image is subsampled into four subimages, and the high correlations among their discrete fractional random transform coefficients are exploited for watermark embedding. Based on this self-reference strategy, the watermark can be extracted without the aid of the host image. As a fragile watermarking technique, our scheme can be used in tamper detection. Besides, it can be used in self-embedding for a large payload is provided. Meanwhile, security of the watermark is preserved due to the randomness of the discrete fractional random transform. Experimental results demonstrate the effectiveness of our scheme. 相似文献
11.
《光学技术》2015,(5):445-450
根据小波变换的高频分量包含边缘及纹理等人眼比较关注的细节信息,提出了一种基于小波变换的高频重构的立体图像质量评价方法,包括左右视点质量评价和立体感评价两部分。通过模拟人类视觉系统处理原始和失真的左右视点图像,利用结构相似度算法得到左右视点质量评价值;用加权处理后的小波高频分量经过重构得到人眼关注的细节信息图,分别计算原始和失真的左右视点细节信息图的绝对差值图,利用结构相似度算法对两幅绝对差值图评价得到立体感质量评价值。将两种质量评价值进行加权融合得到最终的立体图像质量评价值。整体实验结果的Pearson线性相关系数在0.94以上,Spearman秩相关系数值在0.93以上,均方根误差值接近5.5,能较好地符合人眼视觉特性。 相似文献
12.
《中国物理 B》2021,30(7):74201-074201
Single pixel imaging is a novel imaging technique, and it becomes a focus of research in recent years due to its advantages such as high lateral resolution and high robustness to noise. Imaging speed is one of the critical shortcomings, which limits the further development and applications of this technique. In this paper, we focus on the issues of imaging efficiency of a single pixel imaging system. We propose semi-continuous wavelet transform(SCWT) protocol and introduce the protocol into the single pixel imaging system. The proposed protocol is something between continuous wavelet transform and discrete wavelet transform, which allows the usage of those smooth(usually non-orthogonal, and they have advantages in representing smooth signals compressively, which can improve the imaging speed of single pixel imaging) wavelets and with limited numbers of measurements. The proposed imaging scheme is studied, and verified by simulations and experiments. Furthermore, a comparison between our proposed scheme and existing imaging schemes are given. According to the results, the proposed SCWT scheme is proved to be effective in reconstructing a image compressively. 相似文献
13.
采用激光加热小基座法生长出掺Cr3+的蓝宝石光纤荧光温度传感头,它具有结构紧凑,耐高温等特点,测温范围从室温到450℃。使用基于小波变换的数据处理方法,有效去除信号中的噪声,提高了信噪比。在对荧光测温机理和有关光纤技术进行分析的基础上,采用与调制荧光信号相关的双参考源相位锁定测量方案,可在无激励光干扰的情况下对荧光寿命进行实时测量。根据噪音和信号在小波变换下表现出的不同性质,提出以小波变换为基础的温度信号特征提取及消噪方法。与其它处理方法相比,小波变换方法可以克服傅里叶变换对突变信号不起作用的缺点,同时又比Gabor变换具有可变窗口的优点。该方法可以缩短测量时间,提高测量分辨率。 相似文献
14.
15.
16.
17.
针对红外偏振图像可以较好地抑制背景噪声,对目标边缘信息比较敏感的特点,提出一种基于小波变换的红外偏振融合算法,它主要用于红外辐射强度图像和偏振度图像融合,增加图像的信息量。首先采用小波变换对参与融合的每幅图像分别进行各尺度分解,得到各尺度小波系数,然后针对不同尺度小波系数,采用邻域平均梯度为判据进行融合,得到融合后的各尺度小波系数,最后通过小波逆变换进行图像重构,得到融合图像。融合前后的图像对比表明融合图像在保留辐射强度图像的清晰度的同时,突出了目标的边缘、轮廓信息。相对于辐射强度图像,融合图像的梯度均值提高了112%,相对于偏振度图像,融合图像的标准差提高了151%,信息熵提高了38%。 相似文献
18.
基于光学子波变换的SDF匹配滤波器 总被引:2,自引:1,他引:2
提出了一种基于光学子波变换的综合判别函数匹配滤波器(WFSDF),将光学子波变换和综合判别函数相结合,只用一个简单的4f系统就能实现输入图像和SDF子波变换的相关运算。采用计算全息的方法制作复数匹配滤波器。计算机模拟仿真结果表明,与传统的SDF匹配滤波器相比,WFSDF匹配滤波器,锐化了相关峰,提高了识别率,同时简化了光路,能够实现多目标的畸不变识别。 相似文献
19.
基于小波变换和矢量量化的语音压缩编码方案 总被引:3,自引:1,他引:2
对于一种新的语音压缩编码方法——基于小波变换和矢量量化的语音压缩编码方案进行了开发和研究。该方法先对语音进行小波变换和小波包变换,然后使用矢量量化来压缩数据.我们还研究了使用摘编码方法进一步降低比特率的算法,实验结果表明对于采样频率为8kHz,每样本量化为8bit的64kbit/s语音信号压缩到6kbit/s~8kbit/s时,具有良好的语音质量.同时该算法还具有低延迟的优点,其算法延迟只有8ms。 相似文献
20.
随着计算机技术的发展,语音信号处理作为人机交互的重要渠道,其在复杂噪声环境下的特征值检测算法直接关系到计算机的运算效率。基音周期是语音特征值提取的重要参数之一。针对传统基音检测算法在噪声环境下检测精度低的问题,提出了一种基于自适应提升小波变换加权线性预测误差自相关函数的基音检测算法。该方法用多级提升小波近似系数加权求和的方法来弥补自相关函数随着时间延迟量的增加幅值衰减的缺陷;用线性预测误差自相关函数的方法来抑制共振峰的干扰,然后将两种方法结合来突出基音周期处的峰值。实验结果表明,与传统的自相关函数法和小波加权法相比,该方法能有效减弱共振峰的影响,突出基音周期处的峰值,提高基音周期检测精度,鲁棒性更好。 相似文献