一种基于安全隐藏的图像分层窜改检测和内容恢复算法

Fragile watermarking based on secure embedding for hierarchical tampering detection and content recovery

提出了一种可用于数字图像的分层窜改检测和内容恢复的脆弱水印算法。图像中每个分块产生的水印信息包括认证水印和内容恢复水印,其中认证水印由奇偶校验和平均强度信息生成,恢复水印由分块DCT系数量化编码后的信息得到。根据混沌映射和最远距离安全隐藏机制,将恢复水印嵌入到映射块中,可有效避免窜改一致性问题。在接收端,采用分层窜改检测方法,减少窜改分块的漏判和误判,有效提高了窜改精度和恢复质量。实验结果表明,提出的方法与已有方法相比,无论在小面积窜改或大面积窜改情况下均可取得较好的恢复效果。

This paper proposed a novel fragile image watermarking scheme for tampering detection and content recovery. The watermark information for each image block consist of the authentication bits and the recovery bits. It generated the authentication bits by the information of the parity and average intensity, and generated the recovery bits from the encoded DCT coefficients, which embedded into the mapped block according to the chaotic mapping and secure embedding mechanism. On the receiver side, it used the hierarchical tampering detection, which could effectively decrease the missing and misjudgments for tampered blocks. Experimental results show that the proposed scheme can achieve better recovery performance than the repor- ted schemes in both small and large tampered area.