离轴数字全息的正一级像自动重建方法  

Automatic Reconstruction of Positive First-Order Image by Off-Axis Digital Holography

作　　者：刘飞宇 伍秀玭 LIU Feiyu;WU Xiupin(School of Health Science and Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China;School of Medical Instruments,Shanghai University of Medicine&Health Sciences,Shanghai 201318,China)

机构地区：[1]上海理工大学健康科学与工程学院,上海200093 [2]上海健康医学院医疗器械学院,上海201318

出　　处：《电子器件》2024年第3期691-697,共7页Chinese Journal of Electron Devices

基　　金：国家自然科学基金项目(62105197);上海健康医学院科研骨干项目(AMSCP-23-04-01)。

摘　　要：针对离轴数字全息中零级像和共轭像模糊重建像的问题,提出了一种基于峰值信噪比的自动提取正一级频谱并重建其图像的方法。理论上推演并分析了该方法的合理性和可行性,获知了频谱振幅的三个冲激函数点对应于正负一级和零级频谱中心。通过频谱图中的振幅极大值点可确定这三个中心点,然后利用圆形滤波窗提取正一级频谱,并以峰值信噪比为客观评价依据来确定最佳滤波窗半径和重建距离。实验结果表明,所提出的方法可以自动重建离焦全息图像的正一级像,与不滤波重建结果相比,其峰值信噪比提高了32.2%,且比全局阈值分步迭代法提高了7.6%。该方法不依赖于其他先验信息,为离轴全息频谱滤波算法提供了一种新的可行方案。Aiming at the problem of blurring reconstruction of zero-level and conjugate images in off-axis digital holography,a method based on the peak signal-to-noise ratio is proposed to automatically extract the positive first-order spectrum and reconstruct its image.The rationality and feasibility of the method are theoretically deduced and analyzed,and the three impulse function points of the spectral amplitude corresponding to the centers of the positive and negative first-order and zero-order spectrum are known.The three centers can be determined by the amplitude maxima in the spectrogram,then the positive first-order spectrum is extracted by using a circular filter window,and the peak signal-to-noise ratio is used as an objective evaluation basis to determine the optimal radius of filter window and reconstruction distance.The experimental results show that the proposed method can automatically reconstruct the positive first-order image of the out-of-focus hologram,and its peak signal-to-noise ratio is improved by 32.2% compared with the unfiltered reconstruction results,and by 7.6% compared with the global thresholding step-by-step iterative method.The method does not depend on other a priori information and provides a new feasible scheme for off-axis holographic spectral filtering algorithms.

关 键 词：离轴数字全息 正一级频谱 峰值信噪比 滤波窗口半径 离焦图像 

分 类 号：O438.1[机械工程—光学工程]