Zhidong Chen

Large viewing angle three-dimensional display with smooth motion parallax and accurate depth cues

A three-dimensional (3D) display with smooth motion parallax and large viewing angle is demonstrated, which is based on a microlens array and a coded two-dimensional (2D) image on a 50 inch liquid crystal device (LCD) panel with the resolution of 3840 × 2160. Combining with accurate depth cues expressing, the flipping images of the traditional integral imaging (II) are eliminated, and smooth motion parallax can be achieved. The image on the LCD panel is coded as an elemental image packed repeatedly, and the depth cue is determined by the repeated period of elemental image. To construct the 3D image with complex depth structure, the varying period of elemental image is required. Here, the detailed principle and coding method are presented. The shape and the texture of a target 3D image are designed by a structure image and an elemental image, respectively. In the experiment, two groups of structure images and their corresponding elemental images are utilized to construct a 3D scene with a football in a green net. The constructed 3D image exhibits obviously enhanced 3D perception and smooth motion parallax. The viewing angle is 60°, which is much larger than that of the traditional II.

Profile preferentially partial occlusion removal for three-dimensional integral imaging.

A profile preferentially partial occlusion removal method for integral imaging is presented. The profile of the occlusion always contains details with significant texture structure, and regions with significant texture structure often lead to reliable depth estimation. Taking the advantage of the significant texture structure, the profile of occlusion is preferentially dealt with, and then the entire occlusion region is determined via regional spreading according to the accurate profile. The details of occlusion can be accurately removed and the occluded scene is also retained to the maximum degree. In our method, elemental images are integrated into a four-dimensional light field to provide consistently reliable depth estimation and occlusion decisions among all elemental images. Experimental results show that the proposed method is efficient to deal with the details of the occlusion, and it is robust for the occlusions with different kinds of texture structure.

Focus-tunable multi-view holographic 3D display using a 4k LCD panel

A focus-tunable multi-view holographic three-dimensional (3D) display system with a 10.1 inch 4K liquid crystal device (LCD) panel is presented. In the proposed synthesizing method, computer-generated hologram (CGH) does not require calculations of light diffraction. When multiple rays pass through one point of a 3D image and enter the pupil simultaneously, the eyes can focus on the point according to the depth cue. Benefiting from the holograms, the dense multiple perspective viewpoints of the 3D object are recorded and combined into the CGH in a dense-super-view way, which make two or more rays emitted from the same point in reconstructed light field into the pupil simultaneously. In general, a wavefront is converged to a viewpoint with the amplitude distribution of multi-view images on the hologram plane, and the phase distribution of a spherical wave is converged to the viewpoint. Here, the wavefronts are calculated according to all the multi-view images and then they are summed up to obtain the object wave on the hologram plane. Moreover, the reference light (converging light) is adopted to converge the central diffraction wave from the liquid crystal display (LCD) into a common area in a short view distance. Experimental results shows that the proposed holographic display can regenerate the 3D objects with focus cues: accommodation and retinal blur.

High-immersion three-dimensional display of the numerical computer model

High-immersion three-dimensional (3D) displays making them valuable tools for many applications, such as designing and constructing desired building houses, industrial architecture design, aeronautics, scientific research, entertainment, media advertisement, military areas and so on. However, most technologies provide 3D display in the front of screens which are in parallel with the walls, and the sense of immersion is decreased. To get the right multi-view stereo ground image, cameras’ photosensitive surface should be parallax to the public focus plane and the cameras’ optical axes should be offset to the center of public focus plane both atvertical direction and horizontal direction. It is very common to use virtual cameras, which is an ideal pinhole camera to display 3D model in computer system. We can use virtual cameras to simulate the shooting method of multi-view ground based stereo image. Here, two virtual shooting methods for ground based high-immersion 3D display are presented. The position of virtual camera is determined by the peoples eye position in the real world. When the observer stand in the circumcircle of 3D ground display, offset perspective projection virtual cameras is used. If the observer stands out the circumcircle of 3D ground display, offset perspective projection virtual cameras and the orthogonal projection virtual cameras are adopted. In this paper, we mainly discussed the parameter setting of virtual cameras。The Near Clip Plane parameter setting is the main point in the first method, while the rotation angle of virtual cameras is the main point in the second method. In order to validate the results, we use the D3D and OpenGL to render scenes of different viewpoints and generate a stereoscopic image. A realistic visualization system for 3D models is constructed and demonstrated for viewing horizontally, which provides high-immersion 3D visualization. The displayed 3D scenes are compared with the real objects in the real world.

Computer-generated Fresnel Hologram Using Multiple Angular Orthogonal Projection Images

A novel method for a straightforward computer-generated Fresnel hologram using multiple angular orthogonal projection images is presented. Without diffraction calculation and Fourier transforms calculation, the calculation complexity is simplified, and the accuracy is improved.