Bicubic interpolation and extrapolation iteration method for high resolution digital holographic reconstruction

Digital holography enables the digitization processing of holograms. The resolution of the reconstructed image is greatly limited by the pixelated imaging detectors. To improve the resolution, a bicubic interpolation and extrapolation iteration (BIPEPI) method is proposed to compensate the limited size of the digital holograms. Based on the prior knowledge of the model of Fresnel zone plate with circular diffraction gratings, the pixel density is increased by the bicubic interpolation (BIP) method inside the hologram to enhance the low-frequency terms of the object. With extrapolation iterations (EPI) method, more high order fringes outside the hologram are generated to enhance the high-frequency terms of the object. The resolution of the reconstructed image can be effectively improved by combining this predicted low- and high-frequency terms. Numerical simulations and optical experiments are presented and the feasibility of the proposed method is quantitatively evaluated.