应用整数提升小波的图像变容量恢复水印方案

传统的可恢复水印算法往往是通过增加嵌入水印容量来提高篡改图像恢复质量，这将导致嵌入水印后图像质量的下降。针对这一问题，提出使用整数提升小波构建变容量恢复水印算法。该算法根据2×2图像块的纹理特征，使用小波系数生成长度可变的恢复水印，加密后嵌入其他映射图像块低位。使用恢复水印，结合相邻块特征进行篡改图像的检测与恢复。实验结果表明新算法能很好地满足水印不可见性要求，能有效抵抗剪切、拼贴及涂鸦等攻击，能更好地实现篡改图像的恢复。

Image variable capacity recovery watermark scheme using integer lifting wavelet

In order to improve the recovery quality of tampered image, increasing watermark capacity is often used by traditional recovery watermark scheme. But it will lead to watermarked image quality decline. Aiming at the problem, image variable capacity recovery watermark scheme using integer lifting wavelet is proposed. According to the texture feature of 2×2 image block, the variable capacity recovery watermark is generated by using integer lifting wavelet transform coefficients, and embedded into the less significant bit planes of the other mapping image block after encrypted. Connecting with the adjacent block feature, tampered image is authenticated and recovered by using recovery watermark. Experimental results show that this scheme can well meet the requirement of watermark invisibility, and effectively resist attacks such as cropping attack, collage attack and daub attack, and better recover tampered image.