基于第二代Bandelet变换和斜变换的半脆弱水印算法

Semi-fragile watermark algorithm based on second generation Bandelet and slant transform

针对图像的常规操作和恶意攻击,提出一种新的半脆弱水印算法。在该算法中,先将原图像压缩后的数据作为恢复比特嵌入到图像的最低有效位,再把经过Turbo码编码后的第二代Bandelet变换系数嵌入到分块的斜变换的中频区域。认证时,通过Turbo码产生的误码和Bandelet系数的比对实现认证和篡改定位。仿真实验表明,该算法对于图像的常规操作具有良好的鲁棒性,可以精确地检测与定位恶意篡改区域,并且具有较好的篡改恢复能力。

Concerning general image operations and attack method, the paper proposed a new semi-fragile watermarking algorithm. In this algorithm, the recovery bits generated from the compressed original image were embedded into the Least Significant Bits （LSB） of the watermarked image, then the switch coefficients coded by Turbo code after second generation Bandelet transform were embedded in midfrequency blocked regions after slant transform. Authentication could be realized and tampers could be located through comparison between error codes generated by Turbo code and coefficients of Bandelet transform. The experimental results show that the algorithm has enough robustness to general image operations, and can detect and locate the place being maliciously tampered accurately, and has good ability to recover the lost image content.