Analysis and improvement of the watermark strategy for quantum images based on quantum Fourier transform

We investigate the quantum watermark strategy for quantum images based on quantum Fourier transform proposed by Zhang et al.(Quantum Inf Process 12(2):793–803, 2013). It is aimed to embed the watermark image into the Fourier coefficients of the quantum carrier image without affecting the carrier image’s visual effect. However, in our opinion the protocol is not clearly described and several steps are ambiguous. Moreover, we argue that the watermarking algorithm claimed by the authors is incorrect. At last, a possible improvement strategy is presented.     

基于整数小波变换的图像盲数字水印算法

为了提高基于小波变换的图像数字水印算法抵御缩放等攻击的能力,提出了一种基于整数小波变换的图像盲数字水印算法.采用的整数小波变换利用了小波的多分辨分析特性能有效地匹配人类视觉系统模型的特点,更好地兼顾了水印透明性与鲁棒性之间的矛盾;算法中将嵌入的水印作为二值图像进行处理和隐藏,增强了水印所含信息的丰富性和直观性;多个水印副本的嵌入提高了图像抵御攻击的能力;数学形态学中的腐蚀与膨胀运算的运用提高了提取出水印的可辨识度.经过实验证明该算法具有较好的鲁棒性及实用性.     

Dynamic watermarking scheme for quantum images based on Hadamard transform

In this paper, a novel watermarking scheme for quantum images based on Hadamard transform is proposed. In the new scheme, a unitary transform controlled by a classical binary key is implemented on quantum image. Then, we utilize a dynamic vector, instead of a fixed parameter as in other previous schemes, to control the embedding process. The dynamic embedding vector is decided by both the carrier quantum image and the watermark image, which is only known by the authorized owner. The proposed scheme is analyzed from visual quality, computational complexity, and payload capacity. Analysis and results show that the proposed scheme has better visual quality under a higher embedding capacity and lower complexity compared with other schemes proposed recently.     

A dynamic watermarking scheme for quantum images using quantum wavelet transform

In this paper, a novel watermarking scheme based on quantum wavelet transform (QWT) is proposed. Firstly, the wavelet coefficients are extracted by executing QWT on quantum image. Then, we utilize a dynamic vector for controlling embedding strength instead of a fixed parameter for embedding process in other schemes. Analysis and results show that the proposed dynamic watermarking scheme has better visual quality under a higher embedding capacity and outperforms the existing schemes in the literature.     

Quantum representation and watermark strategy for color images based on the controlled rotation of qubits

In this paper, a novel quantum representation and watermarking scheme based on the controlled rotation of qubits are proposed. Firstly, a flexible representation for quantum color image (FRQCI) is proposed to facilitate the image processing tasks. Some basic image processing operations based on FRQCI representation are introduced. Then, a novel watermarking scheme for quantum images is presented. In our scheme, the carrier image is stored in the phase \(\theta \) of a qubit; at the same time, the watermark image is embedded into the phase \(\phi \) of a qubit, which will not affect the carrier image’s visual effect. Before being embedded into the carrier image, the watermark image is scrambled to be seemingly meaningless using quantum circuits, which further ensures the security of the watermark image. All the operations mentioned above are implemented by the controlled rotation of qubits. The experimental results on the classical computer show that the proposed watermarking scheme has better visual quality under a higher embedding capacity and outperforms the existing schemes in the literature.     

基于小波变换的数字水印算法

提出了一种基于小波变换的数字水印隐藏算法.在该算法中,原图像的小波分解区域与水印的小波分解区域相互匹配,水印隐蔽性强,对原始图像的影响基本上察觉不出来.叠加了水印的图像在经过多种强干扰及各种信号处理的变换之后,使用该算法仍能正确检测出水印的存在.     

Hierarchical recovery for tampered images based on watermark self-embedding

In this paper, we propose a new self-embedding watermarking scheme with hierarchical recovery capability. The binary bits in the adopted MSB layers are scrambled and individually interleaved with different extension ratios according to their importance to image visual quality. The interleaved data, which are regarded as reference bits for tampering recovery, are segmented into a series of groups corresponding to the divided non-overlapping blocks, and then embedded into the LSB layers of blocks together with authentication bits of tampering detection. Because the extension ratios of MSB-layer bits are based on the hierarchical mechanism, the efficiency of reference bits is increased, and higher MSB layers of tampered regions have greater probabilities to be recovered than lower MSB layers, which can improve the visual quality recovered results, especially for larger tampering rates. Experimental results demonstrate the effectiveness and superiority of the proposed scheme compared with some of state-of-the-art schemes.     

一种基于含水印量子图像的自适应量子隐写算法

利用NEQR量子图像表示法,提出了一种能在含水印量子载体图像中实现隐蔽通信的量子隐写算法。新算法借助水印通常拥有很好的稳健性和其特有的自恢复系统,对秘密信息的稳健性进行了多重强化。相比于之前的量子隐写算法,新算法不仅强化了秘密信息自身的稳健性,而且通过量子线路的设计提高了其嵌入和提取的可执行性和执行效率。经实验仿真结果和性能分析验证,新算法在保留原有隐蔽性和安全性基础上,进一步提高了秘密信息的稳健性和嵌入率。     

基于小波变换的可见可逆数字水印算法

提出了一种可无损恢复的小波域可见数字水印算法.算法采用视觉对比模型和人类视觉系统特性计算水印拉伸系数,并由用户密钥生成随机模板确定水印信息的嵌入位置.实验结果表明本算法具有很好的可见性和鲁棒性.     

一种印刷品数字水印防伪方法

随着高分辨率扫描印刷设备的出现,印刷品的版权保护成为重要的研究课题。在分析图像经历正版与盗版印刷过程后几何和像素点失真情况的基础上,提出一种基于数字水印技术的印刷品防伪方法。该方法先将水印嵌入到具有几何不变性的Fourier-Mellin域中,以削弱正版印刷过程中的几何失真对水印的破坏;再利用Radon变换对由扫描印刷品所获得的图像进行矫正,并从图像中提取嵌入的水印信息;由于正版和盗版印刷过程对水印的破坏程度区别明显,该方法最终通过计算水印提取的正确率来度量这种破坏,并将其与预先制定的阈值进行比较来判定印刷品的正伪。实验表明,文中提出的半脆弱水印算法克服了已有印刷品防伪水印方法只考虑水印鲁棒性的不足,可用于各类印刷品的版权保护。     

一种基于分数阶Fourier域的数字水印

提出了一种分数阶Fourier域的水印嵌入算法。将一复伪随机序列作为水印信息嵌入到图像的分数阶Fourier域中。分数阶Fourier变换的变换角度(α,β)为水印增加了两个自由度,增强了水印的安全性。仿真结果验证了该算法的有效性。     

基于多变换域的彩色图像多功能水印算法

针对单水印存在功能单一的问题,提出一种基于离散小波变换（DWT）和四元数离散余弦变换（QDCT）的彩色图像多功能水印算法。首先,将彩色图像分通道置乱后进行DWT,选择低、中频子带作分块QDCT,利用部分实数系数构造系数矩阵,鲁棒性水印通过加法原则嵌入该系数矩阵的奇异值中;然后,将图像进行2×2分块的QDCT,特征脆弱水印利用QDCT的低频模值系数产生,并嵌入空域最低有效位（LSB）。实验结果表明,鲁棒性水印具有良好的抗JPEG压缩、噪声、对比度调节、剪切、旋转以及混合攻击的能力,脆弱水印对篡改敏感且具有精确的篡改定位功能。     

基于整数小波变换的彩色图像水印算法

随着Internet的普及和多媒体技术的发展,多媒体信息的安全及版权问题引起了越来越多人的关注,数字水印技术应运而生。整数小波变换能实现从整数到整数的变换,减少了由于浮点数的存在带来的误差,在整数小波变换的基础上设计了一种新的水印嵌入算法,采取了对整数系数进行二值分解后的最后一位进行水印嵌入的方法,且提取时完全不需原始图像,是一种有效的盲水印算法,对各种攻击均具有较好的稳健性。     

基于量子傅里叶变换算法的量子乘法器

乘法运算是许多量子算法中的基本运算之一.为了实现量子乘法运算并且尽可能少地使用辅助量子比特,提出了一种基于量子傅里叶变换算法的量子乘法器.在量子傅里叶加法电路基础上,设计了量子移位电路,并实现了两个n位二进制无符号数相乘的量子电路,其时间复杂度为O(n3).使用IBM提供的开源量子计算工具包Qiskit分别验证了两个2...     

A novel quantum steganography algorithm based on LSBq for multi-wavelength quantum images

In this study, a novel quantum steganography algorithm based on LSBq for multi-wavelength quantum images is proposed. In this study, both the text and the binary image messages are embedded into the cover image. The results of simulations and analysis show that our algorithm satisfies the requirements of steganography algorithms. Also, we used modulo method and Hilbert scrambling method for the security of the hidden message. It is seen that an unauthorized person obtains meaningless information when attempting to extract a embedded information through known methods. The results show that the algorithm is robust against attack when several attacks are applied on the stego-image. Finally, we compare our proposed algorithm with the related works. The results of simulation show that the our proposed algorithm has many advantages according to the related algorithms.     

基于纹理谱的二值文档图像零水印算法

针对二值文档图像的版权保护问题,提出了一种二值文档图像零水印算法。该算法使用文档图像的局部二值模式(LBP)构造纹理谱图像,然后使用该纹理谱图像的直方图构造零水印信息。相比其他文档图像水印算法,该算法具有更好的隐蔽性,而且不会改变原始图像的信息。水印攻击包括图像剪切、加噪声和图像旋转操作,实验分析结果表明这些攻击操作对零水印信息的影响不大,最低标准相关系数在0.85以上,具有很好的稳定性。     

结合SURF特征的多功能彩色图像水印算法

针对目前大多数水印算法功能较单一,提出了一种可以同时进行版权保护和内容认证的多功能彩色图像双水印算法。首先,将原始图像由RGB空间转换到YUV空间,提取亮度分量的SURF（speeded up robust feature）特征点,根据特征点的主方向构造描述向量并将其拆分为两个子向量,分别计算它们与一个参考向量之间的余弦夹角,通过比较夹角的大小关系来构造鲁棒零水印序列;然后对原始图像进行2×2分块,对子图像块奇异值范数进行异或运算来产生脆弱水印信息,并将其嵌入至图像空域的最低有效位。版权归属鉴定时通过计算原始鲁棒零水印序列和从待检测图像中提取的水印序列之间的BCR（bit correct rates）相关系数作为鉴定的依据,内容认证时通过比较图像最低有效位和脆弱水印信息是否一致来实现篡改的检测和定位。实验结果表明,本文算法具有良好的透明性和较高的计算效率,同时具备版权保护和内容认证的双重功能。     

Comment on: Novel image encryption/decryption based on quantum fourier transform and double phase encoding

In this letter, we have pointed out some problems existed in (Yang et al. in Quantum Inf Process 12(11):3477–3493, 2013). Then, a new restricted quantum image color transformation method is proposed.     

基于方向小波与Slant变换的鲁棒水印算法

设计了一种基于内容的数字水印算法。算法以方向小波变换提取的独立分块图像正则方向作为水印信息,根据图像噪声可见函数将水印信息量化嵌入分块图像Slant变换中频系数之中。实验结果显示,算法对于常见图像处理和几何攻击均具有很强的鲁棒性,与基于DCT和PST变换的算法相比,该算法能够更有效地抵抗一些恶意和非恶意操作同时实施的操作。     

基于双分量差值扩展的彩色图像可擦除水印*

针对Tian算法中过度利用差值造成含印图像质量下降严重的问题,提出了基于双分量差值扩展的彩色图像可擦除水印算法。该算法将差值扩展量分散到四个灰度值中,含印图像质量明显提高。实验表明,该方法嵌入的水印不可见性好,擦除水印的图像与原始图像完全相同,适合于图像的精确认证和窜改定位。