Compressive light field display with multilayer and multiframe decompositions is able to provide three-dimensional (3D) scenes with high spatial-angular resolution and without periodically repeating view-zones. However, there are still some limitations on the display performance, such as poor image quality and limited field of view (FOV). Compressive light field display with the viewing-position-dependent weight distribution is presented. When relevant views are given high weights in the optimization, the displaying performance at the viewing-position can be noticeably improved. Simulation and experimental results demonstrate the effectiveness of the proposed method. Peak signal-noise-ration (PSNR) is improved by 7dB for the compressive light field display with narrow FOV. The angle for wide FOV can be expended to 70° × 60°, and multi-viewers are supported.
Conventional gyrocompass alignment methods are based on relatively small azimuth misalignment angles. However, a marine strapdown inertial navigation system may face large azimuth misalignment angle caused by a failed coarse alignment algorithm. This paper provides a novel gyrocompass alignment method to solve the problem. Effects of system parameters are analyzed and the proper scenario of parameter switch based on the classic control theories is derived. Test results show that compared with the conventional methods, our method can accomplish the initial alignment quickly and accurately under large azimuth misalignment angle.
A novel solution for the large view angle holographic head-mounted display (HHMD) is presented. Divergent light is used for the hologram illumination to construct a large size three-dimensional object outside the display in a short distance. A designed project-type lens with large numerical aperture projects the object constructed by the hologram to its real location. The presented solution can realize a compact HHMD system with a large field of view. The basic principle and the structure of the system are described. An augmented reality (AR) prototype with the size of 50 mm×40mm and the view angle above 60 degrees is demonstrated.
A video see-through augmented reality three-dimensional display method is presented. The system that is used for dense viewpoint augmented reality presentation fuses the light fields of the real scene and the virtual model naturally. Inherently benefiting from the rich information of the light field, depth sense and occlusion can be handled under no priori depth information of the real scene. A series of processes are proposed to optimize the augmented reality performance. Experimental results show that the reconstructed fused 3D light field on the autostereoscopic display is well presented. The virtual model is naturally integrated into the real scene with a consistence between binocular parallax and monocular depth cues.
An optical 3D screen usually shows a certain diffuse reflectivity or diffuse transmission, and the multi-projection 3D display suffers from decreased display local contrast due to the crosstalk of multi-projection contents. A tone mapping based optimizing method is innovatively proposed to suppress the crosstalk and improve the display contrast by minimizing the visible contrast distortions between the display light field and a targeted one with enhanced contrast. The contrast distortions are weighted according to the visibility predicted by the model of human visual system, and the distortions are minimized for the given multi-projection 3D display model that enforces constrains on the solution. Our proposed method can adjust parallax images or parallax video contents for the optimum 3D display image quality taking into account the display characteristics and ambient illumination. The validity of the method is evaluated and proved in experiments.
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