Synthesis of computer-generated hologram using Fourier ptychographic approach with intermediate pupil function

Intermediate pupil mask is adopted for synthesis of computer-generated holograms via Fourier ptychographic method. The problem of the conventional Fourier ptychographic method is that the exact target images cannot be created, when it utilized to synthesize computer-generated holograms. In the previous study, the diffraction effect on target images is ignored, and the target images are generated by light-field scheme. However, the mismatched target images degrade the quality of holographic images. The degradation can be mitigated by choosing the optimal size of the sub-regions. The optimal size of the sub-regions can be derived by considering the all-in-focus condition. It is also shown that the computation load can be reduced by setting the pupil mask to Gaussian function. The proposed method has an advantage in computation load for their image quality compared with other hologram synthesis algorithms. The proposed method is verified by numerical simulation.