Method for generating planar computer-generated hologram at free viewpoint from cylindrical object light

Abstract

Computer-generated holography (CGH) is an ideal three-dimensional (3D) display technology, and head-mounted displays (HMDs) using CGH are expected to become the next-generation display devices without eye strain, which is called holographic HMDs (holo-HMDs). However, the CGH computational load is too much for a holo-HMD, which has limited processing power. We have devised a method that calculates the cylindrical object light on a sender, broadcasts the object light data to multiple holo-HMDs, and generates holograms matched to the planar display device on the holo-HMD. The cylindrical object light calculations, which take up most of the computational load, are performed on a high-performance computer with sufficient computational power. The cylindrical object light is transformed into an object light on the plane in accordance with the motion of the holo-HMD. The phase difference information between the complex amplitude distribution of the cylindrical object light and the object light on the plane corresponding to a free viewpoint position must be corrected. Using this method, objects placed near the center of the cylinder can be observed from a wide area, making it possible to support 3D image observation with multiple holo-HMDs. Experiments using an actual optical system demonstrated that planar transform was performed and that the computational load on a holo-HMD side was very small.