不对称分数傅里叶变换计算全息

Computer generated hologram of asymmetry franctional Fourier transform

提出了不对称分数傅里叶变换计算全息,并给出了相应算法。将输入图像信息分别经过x,y不同方向实施不同级次的分数傅里叶变换,采用迂回位相法对其分数域谱编码,绘出计算全息图。再现时需用两个特定的柱面透镜才能再现出所记录的图像信息,利用其再现方式的特殊性可制成一种安全认证系统,计算机上模拟演示结果表明,利用该方法进行安全认证,在防伪力度提高的同时,实际应用也更为方便,具有很高的安全性。

A new optical encryption technique based on computer- generated hologram of asymmetry fractional Fourier transform is presented.In thi s method,the fractional Fourier transform hologram of original object with diff erent orders on axis x and y was coded and ploted into computer-generat ed hologram.In order to reconstruct the encoded image,special fractional Fourier transform systems with certain orders were needed.Because of its particularity of image reconstruction,it was regarded as a new optical security system and cou ld be used in anti-counterfeiting.Computer simulated results show that this met hod can greatly improve the quality of security and anti-counterfeiting,at the same time practical application is more convenient compared to conventional encr yption technique,hence it has wide application and prospect.