基于自适应小波系数的纸币数字水印的实现

Realization of paper currency digital watermarking based on adaptive wavelet coefficient

为了增强纸币的安全性,提出了一种基于小波变换的数字水印技术,并将其应用到纸币防伪中。将纸币号码作为数字水印,经Arnold变换置乱后嵌入到原始纸币图像中。根据人类视觉系统的特性,选择小波系数变化大的位置嵌入数字水印,嵌入数字水印的强度按照小波系数的大小,自适应嵌入低频域中,并采用基于ARM9的嵌入式系统作为数字水印的检测装置以提取数字水印。实验表明该算法在确保纸币水印不可见性的同时,具有较强的抗噪声能力,对纸币的污损、剪切、噪声等操作具有较好的鲁棒性。基于ARM9的嵌入式检测装置可以快速、有效地在点钞的瞬间提取数字水印,满足实际需求。

A digital watermarking technology was presented based on wavelet transform to improve the security of paper currency.The image of paper currency number is scrambled by Arnold transform and embedded into original paper currency image as digital watermark.It embeds digital watermarks into the position of great change of wavelet coefficients according to the characteristics of human visual system.The intensity of the embedded watermarking according to the value of wavelet coefficients is embedded in low frequency domain adaptively.The embedded system based on ARM9 is used as digital watermark detection device to extract the digital watermark.Experiment shows that the digital watermarking algorithm can insure invisibility of digital watermarking and has a better robustness according to damaging,cutting,noising and so on.The embedded detection device based on ARM9 can meet the actual need and extract digital watermark quickly and effectively.