话音通信中的数据自适应隐藏算法

基于话音通信的PCM量化编码,导出了数据嵌入强度因子的选取准则,给出了两种自适应选取的实现策略,进而提出了根据载体信号的幅度以及信道的噪声强度自适应调整的数据隐藏算法.隐藏信息为二进制比特数据时,仿真实验结果表明该自适应隐藏方法具有良好的隐蔽信息传输性能.     

自适应量化索引调制及其信道编码的信息隐藏技术的研究

在信息隐藏通信时,对JPEG-2000小波多级分解并在嵌入块编码中根据不同级的LL-HH分组系数引入自适应量化索引调制(AQIM),同时结合信道编码技术可以有效地实现指纹节点数据的信息隐藏和安全传输技术.通过实验可知,低码率时,与QIM隐藏技术相比,本系统有效地提高了恢复指纹图像的PSNR,同时降低了系统的BER,表明该系统恢复的图像具有更好的感官质量和更强的鲁棒性.     

一种基于小波变换的白适应音频流媒体信息隐藏算法

以音频流媒体信号为载体,应用小波分析与重构、小波快速算法、隐藏门限计算和自适应误差调节等基础理论,提出了一种基于小波变换的自适应信息隐藏算法,并从信息的嵌入和信息的提取两个方面详细阐述了隐藏算法的实现过程,最后给出了仿真实验结果和隐藏效果分析评价。     

一种基于小波变换的自适应音频流媒体信息隐藏算法

以音频流媒体信号为载体,应用小波分析与重构、小波快速算法、隐藏门限计算和自适应误差调节等基础理论,提出了一种基于小波变换的自适应信息隐藏算法,并从信息的嵌入和信息的提取两个方面详细阐述了隐藏算法的实现过程,最后给出了仿真实验结果和隐藏效果分析评价。     

时空域自适应错误隐藏算法

由于解码器后处理错误隐藏技术主要在解码器端完成,不会在码流信息中加入冗余信息,所以解码器后处理错误隐藏技术在实践中得到广泛应用.目前解码器后处理错误隐藏方面已经提出了多种有效的方法,在对比现有的几种时空域错误隐藏的算法的基础上提出了针对视频流中I帧,P帧图像中不同的出错区域采用自适应的时空域错误隐藏算法来恢复原图像,模拟测试表明,该算法能够有效提高视频质量.     

基于非对称数据结构实现信息隐藏通信的方法研究

 数据结构是影响信息隐藏通信实时性能的关键技术.为此,系统设计需要对信源统计、信道状态与传输码率之间进行折衷考虑.按照信息隐藏通信的要求,把信源的统计特性以边信息在解码端进行处理,本文提出了一种非对称数据结构实现信息隐藏通信的方法.结合图像系数的方差分布和不同WNR环境下的信道状态,该方法能够降低了系统编解码实现的复杂性.分别应用SCS和QIM(DC-DM)及SS技术,结果表明,该方法实现的通信系统都具有较好的折衷性能.     

基于视频数字水印的保密通信系统

传统的加密通信不具备伪装性,容易被攻击者截取.为了有效地将信息隐藏实现保密通信,设计了一种基于视频数字水印技术的保密通信系统.该系统将文本信息经海明编码后嵌入到离散余弦变换的系数中来实现信息隐藏,采用直流系数的相对变化关系来实现同步和实时随机检测,能有效克服传统加密通信的缺点.实验表明该系统对视频质量影响较小,能实现隐藏信息的可靠传输.     

基于回声隐藏法的语音信息隐匿

信息隐藏技术对于版权保护和通信保密非常重要。论文将信息隐藏技术用于实现语音安全通信,对语音安全通信的一种新方法——语音回声隐藏技术进行分析和研究,给出了实现该技术的系统方案,并进行仿真和分析,从人耳听觉特性具体要求的角度讨论了该系统的实现细节。     

传统LSB图像隐藏算法的优化研究

信息隐藏技术是信息安全领域的重要组成部分。针对只选最低位的LSB算法会导致隐藏信息量不够大的缺点,提出了优化的LSB算法。该方法在传统的LSB图像隐藏算法的基础上,结合遗传算法,实现秘密信息的自适应嵌入。理论分析和实验表明,这种优化算法不仅具有算法简单、隐蔽性好的特点,还具有隐藏信息容量大、均方根误差小等优点。     

基于第二代Bandelet变换的图像认证水印算法

设计了一种基于第二代Bandelet变换和自适应统计模型的图像认证水印算法.提出了用Bandelet变换生成图像矢量方向流的算法,应用图像的矢量方向流来刻画图像特征,并构造了基于高斯分布统计模型的水印修改自适应噪声可见强度算法.通过噪声可见强度筛选出含纹理信息较多的图像分块隐藏图像矢量方向流.利用提取出的隐藏方向流信息和用Bandelet变换生成的方向流作相关性检测,实现对图像的认证.实验结果表明,该算法有很强的抗JPEG和噪声攻击能力,保证了水印图像的视觉质量和顽健性,实现了盲检测,隐蔽性和安全性较好.     

Improved spread spectrum: a new modulation technique for robust watermarking

This paper introduces a new watermarking modulation technique, which we call improved spread spectrum (ISS). When compared with traditional spread spectrum (SS), the signal does not act as a noise source, leading to significant gains. In some examples, performance improvements over SS are 20 dB in signal-to-noise ratio (SNR) or ten or more orders of magnitude in the error probability. The proposed method achieves roughly the same noise robustness gain as quantization index modulation (QIM) but without the amplitude scale sensitivity of QIM. Our proposed ISS is as robust in practice as traditional SS.     

基于量化的双树复小波变换鲁棒图像水印算法

Conventional quantization index modulation (QIM) watermarking uses the fixed quantization step size for the host signal. This scheme is not robust against geometric distortions and may lead to poor fidelity in some areas of content. Thus, we proposed a quantization-based image watermarking in the dual tree complex wavelet domain. We took advantages of the dual tree complex wavelets (perfect reconstruction,approximate shift invariance, and directional selectivity). For the case of watermark detecting, the probability of false alarm and probability of false negative were exploited and verified by simulation.Experimental results demonstrate that the proposed method is robust against JPEG compression, additive white Gaussian noise (AWGN), and some kinds of geometric attacks such as scaling, rotation, etc.     

Adaptive spread transform QIM watermarking algorithm based on improved perceptual models

The quantization step is one of the most important factors which affect the performance of quantization watermarking used for image copyright protection. According to the characteristic of perceptual model and the specific attacks, improved perceptual model and different implementations of perceptual model are proposed. They are incorporated into the spread transform quantization index modulation (ST-QIM) framework. The experimental results show that the four algorithms we proposed in this paper can reduce the noise attacks and facilitate common digital image processing operations. Among these, adaptive ST-QIM based on further modified Watson model (ST-QIM-fMW-SS) and adaptive ST-QIM based on modified sensitivity model (ST-QIM-MS-SS) have better performance.     

Adaptive Companded Pulse Code Modulation

In this paper, a novel quantization scheme-adaptive companded pulse code modulation (ACPCM)-is proposed. It is shown that, for fine quantization of analog signals, ACPCM will outperform the widely used PCM and DPCM in the sense of minimizing the meansquared quantizing error. For autoregressive (AR)signals, ACPCM is shown to reduce to DPCM. Some examples and simulations are given to demonstrate the method.     

Steganographic data transmission robust against scaling attacks (resistant-to-scaling-attacks) and eliminating the hampering effect of signal-carrier

On the basis of analysis of steganographic system as a communications system with additional information, data transmission algorithms with modulation of the quantization index allowing for elimination of the hampering effect of a signal-carrier have been investigated. It was shown that the choice of quantization step enables us to effectively solve the trade-off task of building a stegosystem: distortions-rate-robustness, while the normalization of quantization step to the root-mean-squre value of signal-carrier in the coder and decoder eliminates the influence of constant multiplicative interference in the channel. Analitical relationships were obtained for the error probability in a channel with additive white noise. Recommendations regarding the selection of transformants of discrete cosine transform (DCT) for imformation embedding into static pictures subjected to the standardized procedure of JPEG DCT compression were given.     

空间调制系统低复杂度的天线选择算法

空间调制(Spatial Modulation,SM)是一种特殊的多天线传输技术,利用发送天线索引和发送的符号共同传递信息.为了获得发送分集增益,人们将天线选择技术应用到SM系统中,提高SM系统解调性能.在天线选择技术中,最大-最小欧式距离(Euclidean Distance Antenna Selection,EDAS)准则应用较为广泛,但是它的全搜索求解方法复杂度高,限制了其应用.为此,本文利用空间调制系统和调制符号本身的特性,从2维量化解调的视角出发,给出了两种低复杂度的最优天线选择算法,并通过计算机仿真和复杂度分析,表明了该算法的有效性和最优性.     

Difference angle quantization index modulation scheme for image watermarking

In this paper, we propose a new angle quantization index modulation (AQIM) method, called the difference AQIM (DAQIM) method. The proposed method aims to improve the watermarking performance against gain attacks. Unlike the original AQIM method (Ourique et al., Angle QIM: a novel watermark embedding scheme robust against amplitude scaling distortions, in: Proceedings of IEEE International Conference on Acoustics, Speech, and Signal Processing, vol. 2, 2005, pp. 797–800), the DAQIM method quantizes the difference of the two angles instead of the angles themselves. The main advantage of the DAQIM method is to disperse the interference to the watermark signal from one angle to more angles. Thus, the watermark has a higher ability to resist attacks. We perform a theoretical analysis of the document-to-watermark ratio (DWR) based on our proposed method. We show that our proposed method can obtain a lower embedding distortion compared to the AQIM and the gradient direction watermarking (GDWM) (Nezhadarya et al., IEEE Trans. Inf. Forensics Secur., 6(4), 2011, 1200–1213), methods under the same robustness and payload conditions. The experimental results demonstrate that our proposed method outperforms common existing methods in terms of the robustness against various attacks such as the JPEG quantization noise, additive white Gaussian noise (AWGN), cropping effect and mean filtering.     

Performance analysis of sign quantized projection

Quantized projection technology(QP) is the version of quantization index modulation(QIM) working in the projection domain.It essentially belongs to a double-sided additive embedder.In this article,the concept of sign quantized projection(SQP) is proposed,which differs from the conventional QP when working as a single-sided embedder.Theoretical analysis reveals that SQP has the same probability of miss and probability of false alarm as QP.Also,the document-to-watermark ratio(DWR) of SQP is less than its coun...     

Quantization noise spectra

Several results describing the behavior of quantization noise in a unified and simplified manner are discussed. Exact formulas for quantizer noise spectra are developed. They are applied to a variety of systems and inputs, including scalar quantization (PCM), dithered PCM, sigma-delta modulation, dithered sigma-delta modulation, two-stage sigma-delta modulation, and second-order sigma-delta modulation