Calculation of large periodic backdrops using numerical propagation with circular convolution in full-parallax high-definition CGHs

A method is proposed for calculating the periodic backdrops that cover the entire field of view in full-parallax high-definition computer-generated holograms (FPHD-CGHs), which can reconstruct very deep 3D scenes without any vergence-accommodation conflict; however, the reconstructed 3D images commonly appear to be floating in empty space, because the computational resources needed to calculate a large backdrop or wallpaper are extremely high. The proposed method expands the apparent sampling window of a backdrop's wavefield using convolution-based numerical propagation with circular convolution. A technique based on the conventional silhouette method is also proposed for occlusion processing in the expanded background. An actual FPHD-CGH was fabricated to demonstrate the validity of the proposed method.