基于菲涅耳域光学图像加密系统的解密研究

为了研究菲涅耳域光学图像加密系统的解密过程,提出了一种根据对称图像加密密文恢复原图像的方法.采用密文全息的逆菲涅耳变换重构出频谱强度,用CCD接收后送入计算机,根据离散菲涅耳变换的相关和复卷积的性质,对其系数进行分类和排列,可以恢复出入射光波,即可恢复原图像.并研究了对称偏差对解密图像质量的影响.结果表明,此方法可以通过离散菲涅耳衍射解密出原对称图像.

Study about decryption based on optical image encryption system in the Fresnel domain

A method was proposed to decrypt the original image from an only ciphertext encrypted from a symmetrical image.Through inverse Fresnel transform of the ciphertext holograph,the intensity of the frequency spectrum can be received by CCD and sent into a computer.According to the characteristics of autocorrelation and complex-convolution in discrete Fresnel transform,the coefficients are classified and ranked,so that the input light wave can be recovered and the original image can be obtained.The effect of the symmetrical deviation on the quality of the decrypted image was also studied.The investigation indicates that the original image can be decrypted by means of discrete Fresnel diffraction.