Voxel-based algorithm for calculating 3D computer generated hologram with occlusion effect

In this paper, a voxel-based algorithm for calculating phase-only three-dimensional (3D) computer generated holograms (CGHs) with occlusion effect is proposed. The 3D object can be firstly decomposed into a number of self-luminous voxels, which is the minimum imaging unit of the object. According to occlusion relationship, the 3D position and propagation direction of each voxel can be determined, where the axial position, lateral position and the propagation direction are precisely controlled by digital Fresnel lens, digital grating and hologram segmentation, respectively. Then, in order to reconstruct the 3D object composed of multiple voxels, the pre-calculated holograms for all of the voxels are synthesized with the interweaving arrangement method. Moreover, the look-up-table (LUT) method is used in the hologram generation process to improve the calculating speed. An experimental verification system for the proposed algorithm is constructed using a single SLM. The optical reconstruction results demonstrate that the CGHs generated by the proposed algorithm can successfully provide 3D sensation with occlusion effect.