Adjustable audio watermarking algorithm based on DWPT and psychoacoustic modeling

This paper presents a novel adjustable audio watermarking method with high auditory quality by exploiting the discrete wavelet packet transform (DWPT), psychoacoustic modeling and distortion compensated-dither modulation (DC-DM) quantization. While the DWPT is used to divide the audio frames into several frequency sub-bands, the psychoacoustic model is intergraded to determine the appropriate sub-bands for watermarking and to control the number of embedded bits in each one. Then, the DC-DM technique is used to embed the watermark bits into the appropriate DWPT coefficients. The synchronization code technique is adopted in the proposed method to withstand desynchronization attacks. In order to achieve an adjustable watermarking scheme, two regulator parameters are provided to manage the capacity-robustness trade-off. The performance of the watermarking scheme is evaluated by examining different host audio signals under various watermarking attacks. The results show excellent imperceptibility of watermarked signals with an average ODG of ? 0.3. In addition, the proposed scheme provides strong robustness against the attacks with low capacity. However, high capacity (about 2500 bps) can be achieved while maintaining a reasonable robustness. A comparison with some state-of-the-art audio watermarking schemes reveals that the proposed method provides competitive results.     

HVS-based scalable image watermarking

This paper proposes a novel human vision system based, spread spectrum method to scalable image watermarking. A scalable decomposition of the watermark is spread into the entire frequency sub-bands of the wavelet decomposed image. At each wavelet sub-band, the watermark data are inserted into the selected coefficients of the sub-band in a manner that the watermark embedding visual artifact occurs in the highly textured, highly contrasted and very dark/bright areas of the image. In the lowest frequency sub-band of wavelet transform, the coefficients are selected by independent analysis of texture, contrast and luminance information. In high frequency sub-bands, the coefficient selection is done by analyzing coefficients amplitude and local entropy. The experimental results show that the watermarked test images are highly transparent and robust against scalable wavelet-based image coding even at very low bit-rate coding. The proposed approach can guarantee content authentication for scalable coded images, especially on heterogeneous networks which different users with different process capabilities and network access bandwidth use unique multimedia sources.

     

A semi-fragile watermarking scheme for authenticating audio signal based on dual-tree complex wavelet transform and discrete cosine transform

In this paper, a novel semi-fragile watermarking scheme for authenticating an audio signal based on dual-tree complex wavelet transform (DT-CWT) and discrete cosine transform (DCT) is proposed. Specifically, the watermark data are efficiently inserted into the coefficients of the low-frequency sub-band of DT-CWT taking advantages of both DCT and quantization index modulation (QIM). First, the original digital audio signal is segmented and then performed with DT-CWT. Second, based on the energy compression property, the low-frequency sub-band coefficients of the DT-CWT domain are performed with DCT, and the DC component is utilized to embed one distorted watermark bit by the QIM technique. Finally, inverse DCT and DT-CWT are orderly implemented on the watermarked coefficients of each audio segment to get a watermarked audio signal. Simulation results show that the hybrid embedding domain constructed by DT-CWT and DCT is effective, and the proposed watermarking scheme is not only inaudible, but also robust against content persistent non-malicious audio signal processing operations, such as MP3 compression, noise addition, re-sampling, re-quantization, etc. Furthermore, the proposed scheme can effectively authenticate the veracity and integrity of audio content and greatly expands the applicability of the audio watermarking scheme.     

An SVD audio watermarking approach using chaotic encrypted images

This paper presents a new approach for audio watermarking using the Singular Value Decomposition (SVD) mathematical technique. The proposed approach can be used for data hiding in the audio signals transmitted over wireless networks and for multi-level security systems as will be stated in the applications section. This approach is based on embedding a chaotic encrypted watermark in the singular values of the audio signal after transforming it into a 2-D format. The selection of the chaotic encryption algorithm for watermark encryption is attributed to its permutation nature, which resists noise, filtering, and compression attacks. After watermark embedding, the audio signal is transformed again into a 1-D format. The transformation between the 1-D and 2-D formats is performed in the well-known lexicographic ordering method used in image processing. The proposed approach can be implemented on the audio signal as a whole or on a segment-by-segment basis. The segment-by-segment implementation allows embedding the same watermark several times in the audio signal, which enhances the detectability of the watermark in the presence of severe attacks. Experimental results show that the proposed audio watermarking approach maintains the high quality of the audio signal and that the watermark extraction and decryption are possible even in the presence of attacks.     

An adaptive color image watermarking using RDWT-SVD and artificial bee colony based quality metric strength factor optimization

Image watermarking has emerged as a useful method for solving security issues like authenticity, copyright protection and rightful ownership of digital data. Existing watermarking schemes use either a binary or grayscale image as a watermark. This paper proposes a new robust and adaptive watermarking scheme in which both the host and watermark are the color images of the same size and dimension. The security of the proposed watermarking scheme is enhanced by scrambling both color host and watermark images using Arnold chaotic map. The host image is decomposed by redundant discrete wavelet transform (RDWT) into four sub-bands of the same dimension, and then approximate sub-band undergoes singular value decomposition (SVD) to obtain the principal component (PC). The scrambled watermark is then directly inserted into a principal component of scrambled host image, using an artificial bee colony optimized adaptive multi-scaling factor, obtained by considering both the host and watermark image perceptual quality to overcome the tradeoff between imperceptibility and robustness of the watermarked image. The hybridization of RDWT-SVD provides an advantage of no shift-invariant to achieve higher embedding capacity in the host image and preserving the imperceptibility and robustness by exploiting SVD properties. To measure the imperceptibility and robustness of the proposed scheme, both qualitative and quantitative evaluation parameters like peak signal to noise ratio (PSNR), structural similarity index metric (SSIM) and normalized cross-correlation (NC) are used. Experiments are performed against several image processing attacks and the results are analyzed and compared with other related existing watermarking schemes which clearly depict the usefulness of the proposed scheme. At the same time, the proposed scheme overcomes the major security problem of false positive error (FPE) that mostly occurs in existing SVD based watermarking schemes.     

Norm ratio-based audio watermarking scheme in DWT domain

In order to reach a balance between robustness, imperceptibility, and data payload, a novel blind audio watermarking scheme is proposed using the norm ratio of approximate coefficients in discrete wavelet domain (DWT). A chaotic sequence generated by Tent map is used to encrypt the watermark image and enhance the security of watermarking system. Firstly the original audio signal is segmented into non-overlapping frames and DWT is applied to each frame. Then, the approximate components are divided into two parts, and the norm ratio is calculated and modulated to embed the watermarks. Finally, the approximate components are scaled by optimizing the quality of the watermarked audio. Experimental results indicate that the proposed watermarking scheme is robust against different common attacks, such as noise addition, resampling, re-quantization, MP3 compression and amplitude scaling. The comparison analysis shows that the proposed scheme has high data payload and provides superior performance compared to the state-of-the-art watermarking schemes.     

An adaptive watermarking approach based on weighted quantum particle swarm optimization

In this paper, we propose a novel optimal singular value decomposition (SVD)-based image watermarking approach that uses a new combination of weighted quantum particle swarm optimization (WQPSO) algorithm and a human visual system (HVS) model for both the hybrid discrete wavelet transform and discrete cosine transform (DCT). The proposed SVD-based watermarking approach initially decomposes the host image into sub-bands; afterwards, singular values of the DCT of the lower sub-band of the host image are quantized using a set of optimal quantization steps deduced from a combination of the WQPSO algorithm and the HVS model. To evaluate the performance of the proposed approach, we present tests on different images. The experimental results show that the proposed approach yields a watermarked image with good visual definition; at the same time, the embedded watermark was robust against a wide variety of common attacks, including JPEG compression, Gaussian noise, salt and pepper noises, Gaussian filters, median filters, image cropping, and image scaling. Moreover, the results of various experimental analyses demonstrated the superiority of the WQPSO approach over other optimization techniques, including classical PSO and QPSO in terms of local convergence speed, resulting in a better balance between global and local searches of the watermarking algorithm.     

Robust multi bit and high quality audio watermarking using pseudo-random sequences

A robust multi bit and high quality audio watermarking technique in time domain is proposed in this paper. Watermarking is a technique used to label digital media by hiding copyright or other information into the underlying data. The watermark must be imperceptible and undetectable by the user and should be robust to various types of distortion. To enhance the robustness and taper-resistance of the embedded watermark, in this paper a multi bit technique is employed. Instead of embedding one bit into an audio frame, multiple bits can be embedded into each audio sub-frame. For attackers, since they do not know the parameters, this significantly reduces the possibility of unauthorized bit detection and removal of watermark. In real-time watermarking applications, robustness is not the only factor that plays an important role. The other factor that plays a very an important role is computational complexity. In general, audio file is transmitted in compressed form. Real-time watermark embedding must take into account this compressed form, because first decompressing the data, adding a watermark and then recompressing the data is computationally too demanding. In this paper, we propose robust and low complexity audio watermarking algorithm. To evaluate the performance of the proposed audio watermarking algorithm, subjective and objective quality tests including bit error rate (BER) and signal-to-noise ratio (SNR) were conducted. Compared to traditional one bit embedding algorithm, the proposed algorithm gives highly recovery rate after attack by commonly used audio data manipulations, such as low pass filtering, requantization, resampling, and MP3 compression.     

Audio watermarking scheme based on embedding strategy in low frequency components with a binary image

With the recent development of information technology and computer network, digital format of data has become more and more popular. However, a major problem faced by digital data providers and owners is protecting data from unauthorized copying and distribution. As a solution to the problem, digital watermark technology is now attracting attention as new method of protection against said unauthorized copying and distribution. The aim of the digital audio watermarking is to take prespecified data that carries certain information and hide it within the audio stream such that it is not audible to the human ear (i.e., transparent) but at the same time renders the file more resistant to removal (i.e., robust). In this paper, we propose a new method for embedding digital watermarks into audio signals in low frequency components, which method mitigates these and other related shortcomings. The proposed method uses the wavelet transform constructed by lifting-based wavelet transform (LBWT) in order to provide a fast implementation between watermark embedding and extraction parts. In the first stage of the proposed method, the original audio host signal is converted to a wavelet domain using LBWT. The signal is thus decomposed into low and high frequency components. Approximation coefficients correspond to low frequency components of the signal. Next, the watermark generated by pseudorandom numbers is embedded into wavelet approximation coefficients of the segmented host audio signal depending on the binary value of the binary image. The reason for embedding the watermark in the low frequency components is that these components' energy is greater than that of high frequency components in such a way that the watermark is inaudible; therefore, it should not alter the audible content and should not be easy to remove. The proposed method uses a binary image to decide whether or not the watermark generated by pseudorandom numbers is embedded in the audio host signal. To evaluate the performance of the proposed audio watermarking method, subjective and objective quality tests including bit error rate (BER) and signal-to-noise ratio (SNR) are conducted. The tests' results show that the proposed method yields a high recovery rate after attacks by commonly used audio data manipulations such as low-pass filtering, requantization, resampling and MP3 compression.     

High payload multi-channel dual audio watermarking algorithm based on discrete wavelet transform and singular value decomposition

Digital watermarking technology is concerned with solving the problem of copyright protection, data authentication, content identification, distribution, and duplication of the digital media due to the great developments in computers and Internet technology. Recently, protection of digital audio signals has attracted the attention of researchers. This paper proposes a new audio watermarking scheme based on discrete wavelet transform (DWT), singular value decomposition (SVD), and quantization index modulation (QIM) with a synchronization code embedded with two encrypted watermark images or logos inserted into a stereo audio signal. In this algorithm, the original audio signal is split into blocks, and each block is decomposed with a two-level DWT, and then the approximate low-frequency sub-band coefficients are decomposed by SVD transform to obtain a diagonal matrix. The prepared watermarking and synchronization code bit stream is embedded into the diagonal matrix using QIM. After that, we perform inverse singular value decomposition (ISVD) and inverse discrete wavelet transform (IDWT) to obtain the watermarked audio signal. The watermark can be blindly extracted without knowledge of the original audio signal. Experimental results show that the transparency and imperceptibility of the proposed algorithm is satisfied, and that robustness is strong against popular audio signal processing attacks. High watermarking payload is achieved through the proposed scheme.     

一种小波变换域上的高鲁棒灰度水印

为了提高灰度水印抵抗滤波,加噪等常见攻击以及几何攻击的能力,提出了一种小波变换域上的高鲁棒水印方案。首先对灰度水印提出了一种新颖的数据压缩方法,并且从中提取出用于水印同步的参考比特。对于受到几何攻击的水印图像,提出了在低频子带上使用图像的主轴和边缘轮廓以获得旋转和缩放参数,从而能准确快速地恢复图像。同时在中频子带上采取了一种对参考比特进行高效匹配的办法来进一步实现水印的同步。实验表明除了一般图像处理之外,对于几何变形攻击本方案具有很好的鲁棒性。     

稳健局部特征非下采样小波域数字水印

目的 基于数字水印技术的音乐作品版权保护是学术界的研究热点之一,多数数字音频水印方案仅仅能够对抗简单的常规信号处理,无法有效抵抗破坏性较强的一般性去同步攻击。为此,提出了一种基于稳健局部特征的非下采样小波域数字水印算法。方法 利用非下采样小波域平滑梯度检测算子从载体音频中提取稳定的音频特征点,结合数字音频样本响应确定局部特征音频段,采用量化调制策略将数字水印信号重复嵌入局部特征音频段中。结果 选取4段典型的采样频率为44.1 kHz、量化精度为16 bit、长度为15 s的单声道数字音频信号作为原始载体进行测试,并与经典算法在不可感知性和鲁棒性两方面进行对比。结果表明,本文算法在含水印音频与原始载体音频间的信噪比平均提升了5.7 dB,同时常规攻击和去同步攻击下的平均检测率分别保持在0.925和0.913,高于大多数传统算法,表明了本文算法具有较好的不可感知性。在常规信号处理（MP3压缩、重新量化、重新采样等）和去同步攻击（幅度缩放、随机剪切、音调伸缩、DA/AD转换、抖动等）方面均具有较好的鲁棒性。结论 本文利用描述能力强且性能稳定的平滑梯度刻画局部数字音频性质,提出一种基于平滑梯度的非下采样小波域音频特征点提取方法,有效解决了音频特征点稳定性差且分布极不均匀的缺点,提高了数字音频水印对音调伸缩、随机剪切、抖动等攻击的抵抗能力。     

DCT域音频水印算法的嵌入位置选择策略

本文在DCT最大误差模型研究的基础上提出了一种新的音频水印嵌入位置选择策略。建立了水印嵌入位置和嵌入水印后的音频文件的听觉感知性之阿的关系,根据音频水印的不可听性的要求选择最优的嵌入位置,然后选择不同的水印强度调整鲁棒性,从而最大程度地保持音频水印的不可听性和鲁棒性,为解决音频水印嵌入过程中不可听性和鲁棒性之间的矛盾提供了一种策略。     

Hybrid Watermarking and Encryption Techniques for Securing Medical Images

Securing medical data while transmission on the network is required because it is sensitive and life-dependent data. Many methods are used for protection, such as Steganography, Digital Signature, Cryptography, and Watermarking. This paper introduces a novel robust algorithm that combines discrete wavelet transform (DWT), discrete cosine transform (DCT), and singular value decomposition (SVD) digital image-watermarking algorithms. The host image is decomposed using a two-dimensional DWT (2D-DWT) to approximate low-frequency sub-bands in the embedding process. Then the sub-band low-high (LH) is decomposed using 2D-DWT to four new sub-bands. The resulting sub-band low-high (LH₁) is decomposed using 2D-DWT to four new sub-bands. Two frequency bands, high-high (HH₂) and high-low (HL₂), are transformed by DCT, and then the SVD is applied to the DCT coefficients. The strongest modified singular values (SVs) vary very little for most attacks, which is an important property of SVD watermarking. The two watermark images are encrypted using two layers of encryption, circular and chaotic encryption techniques, to increase security. The first encrypted watermark is embedded in the S component of the DCT components of the HL2 coefficients. The second encrypted watermark is embedded in the S component of the DCT components of the HH₂ coefficients. The suggested technique has been tested against various attacks and proven to provide excellent stability and imperceptibility results.     

A fuzzy based ROI selection for encryption and watermarking in medical image using DWT and SVD

Nowadays secure medical image watermarking had become a stringent task in telemedicine. This paper presents a novel medical image watermarking method by fuzzy based Region of Interest (ROI) selection and wavelet transformation approach to embed encrypted watermark. First, the source image will undergo fuzzification to determine the critical points through central and final intensity along the radial line for selecting region of interest (ROI). Second, watermark image is altered to time-frequency domain through wavelet decomposition where the sub-bands are swapped based on the magnitude value obtained through logistic mapping. In the each sub-band all the pixels get swapped, results in fully encrypted image which guarantees the watermark to a secure, reliable and an unbreakable form. In order to provide more robustness to watermark image, singular values are obtained for encrypted watermark image and key component is calculated for avoiding false positive error. Singular values of the source and watermark image are modified through key component. Experimental results reveal that the proposed algorithm attains high robustness and improved security to the watermarked image against various kinds of attacks.

     

基于m序列的音频水印隐藏算法

该文提出基于m序列的音频信息隐藏算法,将需要隐藏的水印信息进行m序列的扩展;对数字音频信号进行分段离散小波变换,最后将经过调制的水印信号嵌入到二层小波变换的中频系数中。在接收端,利用盲检测可以精确地提取水印信号。实验仿真结果表明:算法对原始载体音频信号的影响极小,具有较好的鲁棒性和透明性。     

基于音频统计特征的自适应水印方案

基于音频小波域系数的均值和方差特征,提出了一种自适应音频水印方法。通过修改音频帧小波域子带细节系数,使其统计均值按照欲嵌入的水印信息发生改变。根据各音频帧的方差调整水印在不同帧中的嵌入强度,检测水印时不需要原始音频。仿真实验表明水印算法能具有更好的不可感知性,并对常规的音频信号处理,例如滤波、MP3压缩、重采样、重量化、幅度放缩等有良好的稳健性。     

用于MP3作品版权保护的数字水印新算法

以MP3压缩攻击特点与听觉掩蔽特性为基础，提出了一种可用于MP3音乐作品版权保护的混合域数字音频盲水印算法．首先，结合MP3压缩等攻击特点，对原始数字音频进行自适应的分段处理；再对每个音频数据段进行DWT和DCT；最后，结合听觉掩蔽特性与MP3压缩攻击特点，自适应确定量化步长，并将水印信号嵌入到音频数据段的低频分量中．仿真实验表明，所提出的算法不仅具有较好的透明性，而且对诸如重新采样、重新量化、叠加噪声、低通滤波等攻击均具有较好的鲁棒性．特别地，该算法对于最为普通的MP3压缩攻击具有极强的抵抗能力（尤其是高压缩比下）．     

结合视觉密码和离散小波变换的栅格地理数据双重水印

目的 在栅格地理数据的使用过程中,为防止数据被破坏或被篡改,需要加强对数据完整性的检验;为防止数据被恶意传播,需要加强对数据版权信息的保护。双重水印技术可以同时完成这两项任务。方法 利用基于异或的（2,2）-视觉密码方案VCS（visual cryptography scheme）和离散小波变换DWT（discrete wavelet transform）,对数字栅格地理数据嵌入双重水印,使用半脆弱性水印作为第1重水印进行完整性检验,水印信息依据DWT变换后高频系数中水平分量之间的大小关系嵌入;使用零水印作为第2重水印进行版权保护,提取DWT变换后经低频子带奇异值分解的特征值生成特征份,利用基于异或的（2,2）-VCS,根据特征份和水印信息生成版权份。结果 为验证算法的有效性,对具体的栅格地理数据进行实验分析。结果表明,本文算法中第1重水印能够正确区分偶然攻击和恶意破坏,对含水印的栅格地理数据进行质量因子为90、80、70、60、50的JPEG压缩后,提取出完整性水印的归一化相关系数NC（normalized correlation）值分别是1、0.996、0.987、0.9513、0.949,在定位裁剪攻击时,能准确地定位到篡改的位置,对于定位替换攻击时,能定位到篡改的大致位置;第2重水印具有良好的视觉效果和较强的鲁棒性,对含水印的栅格地理数据进行滤波攻击、JPEG压缩、裁剪攻击、缩放攻击等性能测试,提取出版权水印的NC值优于其他方案。结论 论文基于异或的（2,2）-VCS和DWT提出的栅格地理数据双重水印算法,在实现数据完整性检验的同时达到了版权保护的目的。     

基于音频统计特性的数字水印嵌入算法

结合数字音频时频域统计特性及同步码技术, 提出了一种可有效抵抗去同步攻击的混合域数字音频水印嵌入算法. 该算法首先结合数字水印与同步码(大小), 对原始音频载体进行分段处理, 并将每个音频数据段分割成两部分用于嵌入同步码与水印信息; 然后利用时间域音频样本统计特性, 将同步码信息嵌入到音频样本的统计均值上; 最后根据频率域小波系数统计特性, 将数字水印嵌入到低频小波系数的平均值内.