SNR enhancement in in-line particle holography with the aid of off-axis illumination.

The digital in-line particle holography suffers from speckle noise, for which considerable efforts have been devoted in order to mitigate it by designing post-processing algorithms. This paper proposes a novel approach, which mitigates the speckle noise by increasing the signal-to-noise ratio (SNR). It involves the joint design of optical systems and post-processing algorithms, and enhances the SNR by combining several holograms captured under different illumination angles. The experimental results show that the proposed scheme performs better than the normal scheme in terms of SNR and false-detection-ratio.