Opt Lett. 2018 Oct 15;43(20):4993-4996. doi: 10.1364/OL.43.004993.
In off-axis digital holography, the Fourier transform-based algorithm is commonly used for signal processing. Here, we derive the theoretical phase sensitivity of this algorithm, which can be calculated from a single 2D hologram. This algorithm sensitivity represents the best achievable sensitivity of a system using this algorithm. Our derivation treats the signal in its most general form, considering non-uniform illumination and the effect of sideband filtering. As a result, phase sensitivity varies spatially, determined by local signal-to-noise ratio. Sensitivity expressions for both shot noise and uniform noise models are given. These results are validated with simulations and experiments. Significantly, this theoretical sensitivity can serve as a baseline metric for assessing performance of a phase-imaging system, such as experimental sensitivity and hardware stability, which are critical for high-sensitivity quantitative phase imaging. In addition, the results are equally applicable to other interferometric techniques with similar interferogram patterns and signal processing algorithms.
在离轴数字全息术中，基于傅里叶变换的算法通常用于信号处理。在这里，我们推导出了该算法的理论相位灵敏度，该灵敏度可以从单个二维全息图中计算得出。该算法灵敏度代表了使用该算法的系统可实现的最佳灵敏度。我们的推导以最通用的形式处理信号，考虑了非均匀照明和边带滤波的影响。因此，相位灵敏度在空间上变化，由局部信噪比决定。给出了针对散粒噪声和均匀噪声模型的灵敏度表达式。这些结果通过仿真和实验进行了验证。重要的是，该理论灵敏度可以作为评估相位成像系统性能的基准指标，例如实验灵敏度和硬件稳定性，这对于高灵敏度定量相位成像至关重要。此外，该结果同样适用于具有类似干涉图模式和信号处理算法的其他干涉技术。
