Quantum Watermarking Schemes for QHSL Images in Spatial Domain

Three spatial-domain-based quantum watermarking schemes (QWSs) are proposed for quantum hue, saturation, and lightness (QHSL) color model images. Among them, QWS-visible is a visible watermarking scheme in which only the copyright owner who owns both the image mask and key image can remove the visible watermark from the protected image; QWS-lossless is an invisible watermarking scheme that can embed a watermark image in some constrained areas of the image without destroying the image quality; QWS-QRcode embeds a QR code with a color pattern into a carrier image, and uses the error correction mechanism of the QR code to resist a certain degree of cropping attacks. Based on simulation experiments, the QWSs' visual effect, security, applicability, and ability to resist cropping attacks are analyzed. The proposed watermarking schemes set the stage for advancing the research of quantum image watermarking based on the HSL color model.