Quantum color image watermarking scheme based on quantum discrete cosine transform

Abstract Quantum watermarking is a technique that embeds specific informationinto a quantum carrier, used for digital copyright protection. This paper introducesa new quantum color image watermarking method that combines Quantum LOG(QLOG) edge detection with Quantum Discrete Cosine Transform (QDCT) technology.First, edge detection is used on the RGB channels of the quantum color image. Thishelps identify the best channel for embedding the watermark. Next, the image isdecomposed using the quantum Haar wavelet transform (QHWT). The image is thenprocessed with QDCT, selecting the mid-frequency parts for watermark embedding.Using QDCT improves the watermark’s resistance to JPEG compression. Theinvisibility of the watermark is verified by assessing its Peak Signal-to-Noise Ratio(PSNR) and histogram. Comparative analysis shows strong resistance to various noiseattacks. Simulation results confirm that the watermarking technique maintains highvisual quality and resists different adversarial attacks.