Light field displays technologies are popular glasses-free three-dimensional (3D) display methods, whereby natural 3D images can be viewed by precisely reproducing light rays from the objects. However, sufficient display performances cannot be obtained with conventional display techniques because reproduction of a great number of high-density light rays is required for high quality 3D images. Therefore, we develop a novel light field display method named Aktina Vision, which consists of a special 3D screen with isotropic narrow diffusion characteristics and a display optical system for projecting high-density light rays. In this method, multi-view images with horizontal and vertical parallaxes are projected onto the 3D screen at various angles in a superposed manner. The 3D screen has narrow diffusion angle and top-hat diffusion characteristics for optimal widening of the light rays according to the discrete intervals between the rays. 3D images with high resolution and depth-reproducibility can be displayed by suppressing crosstalk between light rays and reproducing them with continuous luminance distribution. We prototype a display system using 14 exclusively designed 4K projectors and develop a light field calibration technique. The reproduction of 3D images with a resolution of approximately 330,000 pixels, which is three times higher than that of conventional display methods using a lens array, and viewing angles of 35.1° in the horizontal direction and 4.7° in the vertical direction is realized by projecting 350 multiview images in a superposed manner.
Light field displays can provide a naturally viewable three-dimensional (3D) image without the need for using special glasses. However, improving in the resolution of 3D images is difficult because considerable image information is required. Therefore, we propose two new light field display methods that use multiple ultra-high definition projectors to realize a reproduction of a high-resolution spatial image. One of the two proposed methods is based on integral imaging. Multi-elemental images are superimposed onto a lens array using multiple projectors placed at optimal positions. An integral 3D image with enhanced resolution and viewing angle can be reproduced by projecting each elemental image as collimated light rays at different predetermined angles. We prototyped a display system having six projector units and realized a resolution of approximately 100,000 pixels and viewing angle of approximately 30°. The other proposed method aiming at further resolution enhancement is based on multi-view projection. By constructing a new display optical system to reproduce a full parallax light field and by developing a special 3D screen with isotropic narrow diffusion characteristics of non-Gaussian shape, optical 3D images could be reconstructed, which was difficult with conventional methods. We prototyped a display system comprising two projector units and realized higher resolution of approximately 330,000 pixels as compared to our previous full parallax light field display systems.
We studied an integral three-dimensional (3D) TV based on integral photography to develop a new form of broadcasting that provides a strong sense of presence. The integral 3D TV can display natural 3D images that have motion parallax in the horizontal and vertical directions. However, a large number of pixels are required to obtain superior 3D images. To improve image quality, we applied ultra-high-definition video technologies to an integral 3D TV system. Furthermore, we are developing several methods for combining multiple cameras and display devices to improve the quality of integral 3D images.
We propose a method for arranging multiple projectors in parallel using an image-processing technique and for enlarging the viewing zone in an integral three-dimensional image display. We have developed a method to correct the projection distortion precisely using an image-processing technique combining projective and affine transformations. To combine the multiple viewing zones formed by each projector continuously and smoothly, we also devised a technique that provides accurate adjustment by generating the elemental images of a computer graphics model at high speed. We constructed a prototype device using four projectors equivalent to 4K resolution and realized a viewing zone with measured viewing angles of 49.2 deg horizontally and 45.2 deg vertically. Compared with the use of only one projector, the prototype device expanded the viewing angles by approximately two times in both the horizontal and vertical directions.
The quality of the integral 3D images created by a 3D imaging system was improved by combining multiple LCDs to utilize a greater number of pixels than that possible with one LCD. A prototype of the display device was constructed by using four HD LCDs. An integral photography (IP) image displayed by the prototype is four times larger than that reconstructed by a single display. The pixel pitch of the HD display used is 55.5 μm, and the number of elemental lenses is 212 horizontally and 119 vertically. The 3D image pixel count is 25,228, and the viewing angle is 28°. Since this method is extensible, it is possible to display an integral 3D image of higher quality by increasing the number of LCDs. Using this integral 3D display structure makes it possible to make the whole device thinner than a projector-based display system. It is therefore expected to be applied to the home television in the future.
A three-dimensional (3D) capture system based on integral imaging with an enhanced viewing zone by using a camera array was developed. The viewing angle of the 3D image can be enlarged depending on the number of cameras consisting of the camera array. The 3D image was captured by using seven high-definition cameras, and converted to be displayed by using a 3D display system with a 4K LCD panel, and it was confirmed that the viewing angle of the 3D image can be enlarged by a factor of 2.5 compared with that of a single camera.