Quantum image watermarking technology based on quantum wavelet transform

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.