High-resolution reconstruction in off-axis digital holographic imaging by using aliasing-spectrum filtering

We present a spectrum filtering approach for reconstruction of off-axis digital holograms. The high frequency aliasing terms in Fourier spectrum domain of hologram are generated by non-fitting interpolation. After interpolation processing, the zero-order terms in the aliasing spectrum region are obviously suppressed. Accordingly, for the spectrum filtering of high-frequency signal terms, the available range of frequency band will increase significantly, which can result in the improvement of resolution of the reconstructed images. In order to avoid the effect of non-uniform distribution on the aliasing spectrum terms, all the same-order signal terms in the aliasing spectrum (positive or negative first-order spectrum) are intercepted, respectively, and then added together to reconstruct the complex amplitude distribution of the sample. We perform the reconstruction imaging with a conventional method and the presented method from the same hologram in simulation. The imaging results show that such interpolation method can obviously improve the resolution of the reconstructed amplitude and phase images. This method for off-axis digital holographic reconstruction only relies on a single frame acquisition to achieve high resolution reconstruction imaging without additional requirements to the optical setup, which will have a promising application in real-time imaging for living biological cells or moving objects.