Adaptive LSB quantum image watermarking algorithm based on Haar wavelet transforms

In this paper, a novel scheme for quantum image watermarking based on novel enhanced quantum representation of digital images (NEQR) is proposed which can embed a 2(n-1) x2(n-1) binary watermark image into a 2(n) x2(n) grayscale carrier image. Since only the least significant bits of the diagonal details of the carrier image are embedded with the watermark information, the embedded image is highly consistent with the carrier image after restoration. Again by reversing the embedding, the copyright owner can simply extract the watermarked image. The simulation technique confirms the invisibility and robustness of the proposed watermarking method. The embedded watermarked image and the carrier image are highly relevant, with peak signal-to-noise ratio (PSNR) above 48 dB, structural similarity index metric (SSIM) above 0.997 and correlation coefficient ( R) above 0.994. The robustness of the proposal is demonstrated by checking the bit error rate (BER) count and R after it has been attacked. Through the above embedding method, the watermarked image can ensure its robustness and achieve better visual effects.