Fig. 1. Fresnel diffraction and θ modulation system for color image. 彩色图像的菲涅尔衍射和θ调制系统

Fig. 2. Color image to be encrypted.待加密彩色图像

Fig. 3. Flow chart of color image encryption by computer generated hologram.彩色图像加密的计算全息编码流程图

Fig. 4. (a) The encrypted image; (b) the encrypted computer generated hologram.(a)加密结果图; (b)加密计算全息图

Fig. 5. Decryption system of color image.彩色图像解密系统

Fig. 6. Decrypted color image.解密彩色图像

Fig. 7. Decrypted results with wrong keys: (a) Wrong key ; (b) wrong key Fresnel diffraction distance with . 密钥错误时的解密结果　(a)相位密钥 错误; (b)菲涅耳衍射距离错误( )

Fig. 8. Tricolor components of color image: (a) Red component; (b) green component; (c) blue component; (a'), (b'), (c') red, green and blue components of original color image.解密彩色图像三基色分量　(a)红色分量; (b)绿色分量; (c)蓝色分量; (a'), (b'), (c')原始图像三基色分量

Fig. 9. Shear attack of different levels and image restoration after shear attack.不同程度的剪切攻击和剪切攻击后的恢复图像

Fig. 10. (a)－(d) Encrypted images with salt and pepper noises with density of 0.1, 0.3, 0.5 1.0; (a')－(d') corresponding decryption results.(a)—(d)分别加入密度0.1, 0.3, 0.5和1.0的椒盐噪声后的加密图像; (a')—(d')相应的解密结果图