Masahiro Kawakita

3D image quality of 200-inch glasses-free 3D display system

We have proposed a glasses-free three-dimensional (3D) display for displaying 3D images on a large screen using multi-projectors and an optical screen consisting of a special diffuser film with a large condenser lens. To achieve high presence communication with natural large-screen 3D images, we numerically analyze the factors responsible for degrading image quality to increase the image size. A major factor that determines the 3D image quality is the arrangement of component units, such as the projector array and condenser lens, as well as the diffuser film characteristics. We design and fabricate a prototype 200-inch glasses-free 3D display system on the basis of the numerical results. We select a suitable diffuser film, and we combine it with an optimally designed condenser lens. We use 57 high-definition projector units to obtain viewing angles of 13.5°. The prototype system can display glasses-free 3D images of a life-size car using natural parallax images.

A hybrid representation for multi-view images

There are several representations for 3D scene that are used for 3DTV and free viewpoint imaging systems. A well-known representation is sparse view-plus-depth. Based on view-plus-depth, layered depth video (LDV), and FTV data Unit (FDU) were proposed. The represented images by them are based on residual values. For view data in view-plus-depth, we propose a novel representation; consist of original and hybrid images that are repeated consecutively. A hybrid image has residual and reminder pixels. A virtual image is synthesized in both generation and reconstruction of the hybrid image. The reconstruction is the compensation of the virtual image using the hybrid image. The reconstructed hybrid image has higher PSNR and fewer visible artifacts than the virtual view compensated by residual or reminder image. The data size of the hybrid images is also less than residual and reminder images.

3D video capturing for multiprojection type 3D display

We have already developed glasses-free three-dimensional (3-D) displays using multi-projectors and a special diffuser screen that results in a highly realistic communication system. The system can display 70-200 inch large-sized 3-D images with full high-definition video image quality. The displayed 3-D images were, however, only computergenerated graphics or still images of actual objects. In this work, we studied a 3-D video capturing method for our multiprojection 3-D display. We analyzed the optimal arrangement of cameras for the display, and the image quality as influenced by calibration error. In the experiments, we developed a prototype multi-camera system using 30 highdefinition video cameras. The captured images were corrected via image processing optimized for the display. We successfully captured and displayed, for the first time, 3-D video of actual moving objects in our glasses-free 3-D video system.

Analysis of resolution limitation of a glasses-free tabletop 3D display

In this research we investigate the maximum displayable angular resolutions in the horizontal and vertical directions of a planar 3-D object displayed by a glasses-free tabletop 3-D display that is using a conic-shaped optical device and an array of projectors. We estimate initially the resolutions of the (1) slit-like views corresponding to each projectors image and then continue with the resolution for the (2) final 3-D image obtained after the integration of the slits. Our experimental results represent a first attempt in estimating the differences between these resolutions that can benefit (1) future tunings of the tabletop 3-D display as well as (2) optimization of the displaying process.

200-Inch glasses-free 3D display and electronic holography being developed at NICT

National Institute of Information and Communications Technology (NICT) is conducting ultra-realistic communication research since 2006. The aim of this research is to create a sense of “being there” for natural and realistic communication. In this research project, NICT has developed some novel glasses-free 3D display systems. Among these systems, a large-size glasses-free 3D display using super-multi-view 3D video technologies and an electronic holography system using laser light are introduced in this paper.

3D imaging for glasses-free multiview 3D displays

The multi-view three-dimensional (3D) visualization by means of a 3D display requires reproduction of scene light fields. The complete light field of a scene can be reproduced from the images of a scene ideally taken from infinite viewpoints. However, capturing the images of a scene from infinite viewpoints is not feasible for practical applications. Therefore, in this work, we propose a sparse camera image capture system and an image based virtual image generation method for 3D imaging applications. We show a resulting virtual image produced by the proposed algorithm for generating in-between view of two real images captured with our multi-camera image capture system.