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基于对抗神经网络的反射面天线单输入口径场相位恢复方法

Adversarial Neural Network-Based Phase Retrieval from Single Far-Field Data for Reflector Antennas

  • 摘要: 微波全息测量技术在反射面天线表面测量中广泛应用, 其中相位恢复方法因其不需要额外专门设备而广泛应用于射电望远镜的面形校准. 该方法通过天线远场强度数据, 通常利用一定的反演算法通过口径场与远场数据迭代获取近似口径场相位的过程. 为了提高解算效率, 采用深度学习技术, 基于条件生成对抗网络(Conditional Generative Adversarial Network, CGAN)方法设计了一种模型用于在单输入远场幅值下解决反射面天线口径场相位恢复的问题. 基于该模型的相位恢复方法放弃了传统方法对先验知识的依赖以及耗时的迭代过程. 在原来CGAN的损失函数中, 结合了引入均方误差(Mean Square Error, MSE)和结构相似性指数(Structural Similarity Index Measure, SSIM)损失函数, 以优化网络训练, 提高相位恢复精度. 验证表明, CGAN网络对泊松噪声具有鲁棒性, 可用作相位恢复过程中的降噪工具. CGAN框架不仅提升了相位恢复精度, 降低了计算复杂度, 而且有助于解决傅里叶成像系统中的相位恢复问题, 该方法还可用于其他领域的位相误差测量.

     

    Abstract: Microwave holographic measurement technology is widely utilized in the surface measurement of telescopes, among which the phase recovery method is extensively applied in the surface calibration of radio telescopes due to its elimination of the need for additional specialized equipment. This method typically employs inversion algorithms to iteratively obtain an approximate near-field phase from far-field intensity data of the antenna. To enhance computational efficiency, this paper adopts deep learning techniques and designs a model based on the Conditional Generative Adversarial Network (CGAN) approach to address the issue of near-field phase recovery for reflector antennas under single-input far-field amplitude conditions. The phase recovery method proposed by this model dispenses with the traditional reliance on prior knowledge and the time-consuming iterative process. The original CGAN loss function has been augmented by incorporating Mean Squared Error (MSE) and Structural Similarity Index (SSIM) loss functions to optimize network training and improve the precision of phase recovery. Validation has shown that the CGAN network is robust against Poisson noise and can serve as a denoising tool in the phase recovery process. The CGAN framework not only enhances the precision of phase recovery and reduces computational complexity but also contributes to solving phase recovery issues in Fourier imaging systems. Moreover, this method can be extended to phase error measurement in other fields.

     

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