一种基于脆弱水印技术的图像认证方法

A Method for Image Authentication Based on Fragile Watermarking

基于计算全息图编码的水印技术是一种脆弱水印技术,由于其极容易被破坏的特性,非常适合用于图像内容的认证,在图像的认证鉴定的时候,通过比较提取的水印和初始水印的相关性鉴定图像内容的完整性,可以有效防止篡改和对修改图像的欺骗性应用。同时,图像的内容被篡改时,水印信息应该提供图像被伪造的证据。利用计算全息图作为水印,嵌入的水印可能被使用傅里叶变换恢复,进而,宿主图像也能被利用同样的全息模式进行篡改和嵌入水印,为了避免这种弊端,还需要引入加密方法。

In this paper a content fragile watermarking based on computer generated hologram coding technique is presented. This technology is fit for image authentication exactly because the CGH watermark is prone to be destroyed. Content fra - gile watermarking techniques aim to prevent tampering and fraudulent use of modified images. Therefore,if parts of tbe image are replaced,the watermark information should indicate evidence of forgery. Using computer generated hologram watermarking,the embedded mark could be recovered by means of a Fourier transform. Due to this fact the host image can be tampered and watermarked with the same holographic pattern. So, an encryption method must be included to avoid this possibility. It could be applied to color images and grey - scale ones. The integrity of the image would be verified by the correlation between the original mark and the extracted one.