目的 为了解决当前基于干涉原理的光学图像加密算法因存在轮廓显现导致其安全性不高的问题，提出双光束相干叠加与差异模矢量分解的图像加密算法。方法 基于Gyrator变换，将明文变成一个Gyrator频域的复杂函数；随后引入矢量分解方法，将Gyrator频域复杂函数进行差异分解，输出幅度与相位不均等的2个矢量成分；利用2个相位掩码对矢量成分进行调制，将其从频域变为空域，将其相位部分视为私密，而幅度部分视为最终加密密文。结果 实验显示，与当前基于模均等分解的图像加密技术相比，所提算法具有更高的保密性与敏感性，有效消除了轮廓显现问题。结论 所提算法能够确保图像信息在网络中的安全传输，有效抵御外部攻击，在包装印刷与防伪二维码等领域具有一定的应用价值。

The work aims to put forward the image encryption algorithm based on double beam coherent superposition and differential mode vector decomposition, in order to solve the problem of low security induced by silhouette existing in current optical image encryption algorithm based on the principle of interferometry. Firstly, the plaintext was transformed into complex function in Gyrator domain based on Gyrator transform. Then, upon the introduction of vector decomposition method, the complex function in Gyrator domain was differentially decomposed into two vector components with unequal output amplitude and phase. The vector components were modulated by two phase masks for taking it from the frequency domain to the spatial domain, of which the phase part was regarded as private, and the amplitude part was regarded as the final encrypted cipher. The experimental results showed that, compared with the current image encryption technology based on the equal mode decomposition, the proposed algorithm had higher security and sensitivity that effectively eliminated the silhouette problem. The proposed algorithm can ensure the secure transmission of image information in the network, and effectively resist external attacks. It has certain application value in the field of packaging, printing and anti-counterfeiting QR code.