A novel watermarking scheme for quantum image is proposed based on Quantum cosine transform (QCT). The cosine coefficients are extracted by executing QCT on quantum image. A dynamic vector for controlling embedding strength instead of a fixed parameter for embedding process in other scheme is utilized to process quantum watermark. The adder operation and the inverse QCT are implemented which offset the QCT and guarantee the embedding process having smaller impact on the quantum carrier image. Simulation results and analysis show that the proposed dynamic watermarking scheme has better visual quality under a higher embedding capacity.
A novel watermarking scheme for quantum image is proposed based on Quantum cosine transform (QCT). The cosine coefficients are extracted by executing QCT on quantum image. A dynamic vector for controlling embedding strength instead of a fixed parameter for embedding process in other scheme is utilized to process quantum watermark. The adder operation and the inverse QCT are implemented which offset the QCT and guarantee the embedding process having smaller impact on the quantum carrier image. Simulation results and analysis show that the proposed dynamic watermarking scheme has better visual quality under a higher embedding capacity.
A universal watermarking protocol for quantum images is designed in this paper. The protocol is developed based on quantum transform (QT) and quantum add operation (QAO). Moreover, a dynamic vector is introduced to control the embedding strength in the embedding process, which is obtained through the constraint that quantum image state should keep normalized in the entire computation process. Therefore, the dynamic vector is an optimal solution of an optimization equation, which makes the watermarked image with better visual quality. Compared with the other protocols or schemes, the proposed one can improve watermarking performance of visual quality and capacity. Experiments based on flexible representation of quantum image (FRQI) and Quantum Fourier transform (QFT) illustrate the superior effectiveness of the proposed protocol.
As one of the important branches of quantum image processing, quantum image watermarking technology has been studied by many related personnel. However, most of them are performed in the time domain, and there are relatively few algorithms for quantum image watermarking in the transform domain. This paper proposes a quantum image watermarking technology based on quantum D4 wavelet transform, which specifically includes several aspects. Combining quantum wavelet transform and controlled-rotating gate, this paper proposed a quantum image watermarking algorithm for the modified flexible representation of quantum images (FRQIM) and the normal arbitrary superposition state (NASS). Firstly, the wavelet coefficients of the image are obtained by quantum wavelet transform, then the rotating gate is designed by the information of the watermark image, then the embedding position of the watermark image information is controlled by the controlled gate, and finally the watermark information is embedded in the carrier image by the controlled-rotating gate. This scheme makes full use of the parallelism of quantum computing and can operate on two images at the same time. The simulation results show that for different image combinations, the embedded image is not significantly different from the original image. Compared with the quantum image watermarking algorithm that uses the quantum Fourier transform, the image distortion after watermarking is smaller, and there are more options for embedding the image.
In this paper, a novel frequency domain quantum watermarking scheme is proposed based on the Flexible Representation of Quantum Images, which can embed a 2n1× 2n1binary watermark image into a 2n× 2ngrayscale carrier image. The quantum Haar wavelet transform is developed and used to decompose quantum images. The diagonal detail coefficients of the carrier image are obtained from the image decomposition. Then, according to the watermark image information, the diagonal wavelet coefficients are either unchanged or slightly modified. Since all of the used quantum operations are invertible, extraction of the watermark image is performed in a straightforward manner by reversing the watermarking embedding process. Finally, the proposed quantum image watermarking scheme is simulated on a classical computer and evaluated under different carrier and watermark images. The simulation results and performance analyses indicate the high performance of the presented watermarking scheme in terms of the similarity between the watermarked and carrier images.
Most of the studied quantum encryption algorithms are based on square images. In this paper, based on the improved novel quantum representation of color digital images model (INCQI), a quantum color image watermarking scheme is proposed. First, INCQI improved from NCQI is used to represent the carrier and watermark images with the size [Formula: see text] and [Formula: see text], respectively. Secondly, before embedding, the watermarking needs to be preprocessed. That is, the watermark image with the size of [Formula: see text] with 24-qubits color information is disordered by the fast bit-plane scramble algorithm, and then further expanded to an image with the size [Formula: see text] with 6-qubits pixel information by the nearest-neighbor interpolation method. Finally, the dual embedded algorithm is executed and a key image with 3-qubits information is generated for retrieving the original watermark image. The extraction process of the watermark image is the inverse process of its embedding, including inverse embedding, inverse expand and inverse scrambling operations. To show that our method has a better performance in visual quality and histogram graph, a simulation of different carrier and watermark images are conducted on the classical computer’s MATLAB.
The study presented in this work explores the implementation of a watermarking scheme for quantum audio signals based on quantum Discrete Cosine Transformation (qDCT). The qDCT transforms the quantum host audio signal which is encoded as an FRQA (flexible representation of quantum audio) content from time domain to frequency domain and manipulates or modifies the high-frequency positions to embed the quantum watermark audio information into it. The strong energy compaction property of DCT is utilized in this scheme, i.e. after the DCT process to a digital audio, most of the signal information tends to be concentrated in a few low-frequency components and its high-frequency components could record some extra information like watermark audio. Built on the circuit model of quantum computation, the circuit networks to execute the embedding and extraction procedures of qDCT-based watermarking algorithm are designed and simulation-based experiments are conducted to demonstrate their implementation.
This paper presents a spatial domain quantum watermarking scheme. For a quantum watermarking scheme,a feasible quantum circuit is a key to achieve it. This paper gives a feasible quantum circuit for the presented scheme. In order to give the quantum circuit, a new quantum multi-control rotation gate, which can be achieved with quantum basic gates, is designed. With this quantum circuit, our scheme can arbitrarily control the embedding position of watermark images on carrier images with the aid of auxiliary qubits. Besides reversely acting the given quantum circuit, the paper gives another watermark extracting algorithm based on quantum measurements. Moreover, this paper also gives a new quantum image scrambling method and its quantum circuit. Differ from other quantum watermarking schemes, all given quantum circuits can be implemented with basic quantum gates. Moreover, the scheme is a spatial domain watermarking scheme, and is not based on any transform algorithm on quantum images. Meanwhile, it can make sure the watermark be secure even though the watermark has been found. With the given quantum circuit, this paper implements simulation experiments for the presented scheme. The experimental result shows that the scheme does well in the visual quality and the embedding capacity.