Parameter determination for the optical path of digital holography based on improved particle swarm optimization

In digital holography (DH), the key parameters in the optical path structure, such as diffraction distance, optical path difference and deflection angle, affect greatly the image quality of holographic reconstruction. Thus, it is crucial to determine the appropriate values of parameters. In this paper, the influence of these parameters on the quality of reconstructed images is deeply analysed through the DH principle and numerical simulation. A method to optimize automatically the parameters in the optical path is proposed based on an improved particle swarm optimization algorithm. An experimental setup for reflective off-axis DH is constructed, and coin and optical resolution plate are taken as test samples to perform the experimental research. Experimental results demonstrate that the proposed method can not only effectively enhance the quality of reconstructed images in the light of five indicators but also reduce the complexity and difficulty of adjusting the optical path parameters in the experiments.