This paper describes a new system for sharing a 3D space on workbenches placed at different locations. It consists of
flatbed-type autostereoscopic displays based on the one-dimensional (horizontal parallax only) integral imaging (1D-II)
method and multi-viewpoint video cameras. Possible applications of the system include a tool for remote instruction,
where an instructor can show how to assemble a product from given parts to a worker who is not in front of the instructor
but in a different room or factory. The idea of sharing the 3D space at different locations is not new. In the previous
applications such as mixed reality, however, since the depth of the reconstructed 3D space was not clearly restricted, it is
difficult to improve the image quality of the reconstructed space. In the application presented in this paper, we can obtain
a reasonable level of the image quality because the depth of the reconstructed space is clearly limited by the size of the
parts on the 3D workbench. A new multi-viewpoint video camera was designed for the application. In this design, each
image sensor was placed parallel to the lens with a shift in each direction of the XY coordinate system in a horizontal
plane and only a limited region of each image was used to reconstruct the 3D space. An experimental system called the
"3D hand-area space sharing system" was implemented using integral imaging 3D displays as well as multi-viewpoint
video cameras. As a result, we ascertained that larger display, namely, 8K4K, and interpolation technology are necessary
for a multi-viewpoint video camera for the 3D hand-area space sharing system.
A display system with lens arrays at the front of a high-resolution LCD has been known as a method to realize an
autostereoscopic three-dimensional (3D) display. In these displays, a light ray overlap between neighboring parallax
images affects the image quality. In this study, the overlap effects were investigated for the one-dimensional (horizontal
parallax only) integral imaging (1D-II) method. We fabricated samples of 1D-II displays with different levels of light ray
overlaps and evaluated the 3D image by subjective assessment. It is found that the 1D-II display utilizing the proper
parallax overlaps can eliminate banding artifact and have good 3D image quality within the wide range of a viewing area.
We have developed prototypes of flatbed-type autostereoscopic display systems using one-dimensional integral imaging
method. The integral imaging system reproduces light beams similar of those produced by a real object. Our display
architecture is suitable for flatbed configurations because it has a large margin for viewing distance and angle and has
continuous motion parallax. We have applied our technology to 15.4-inch displays. We realized horizontal resolution of
480 with 12 parallaxes due to adoption of mosaic pixel arrangement of the display panel. It allows viewers to see high
quality autostereoscopic images. Viewing the display from angle allows the viewer to experience 3-D images that stand
out several centimeters from the surface of the display. Mixed reality of virtual 3-D objects and real objects are also
realized on a flatbed display. In seeking reproduction of natural 3-D images on the flatbed display, we developed
proprietary software. The fast playback of the CG movie contents and real-time interaction are realized with the aid of a
graphics card. Realization of the safety 3-D images to the human beings is very important. Therefore, we have measured
the effects on the visual function and evaluated the biological effects. For example, the accommodation and convergence
were measured at the same time. The various biological effects are also measured before and after the task of watching
3-D images. We have found that our displays show better results than those to a conventional stereoscopic display. The
new technology opens up new areas of application for 3-D displays, including arcade games, e-learning, simulations of
buildings and landscapes, and even 3-D menus in restaurants.
We have developed a flatbed-type autostereoscopic display system showing continuous motion parallax as an extended form of a one-dimensional integral imaging (1D-II) display system. The 1D-II display architecture is suitable for both flatbed and upright configurations. We have also designed an image format specification for encoding 1D-II data. In this parallax image array format, two (or more) viewpoint images whose viewpoint numbers are separated by a constant number are paired, and all of the paired images are combined to obtain an image the same size as the elemental image array. By using the format, 3-D image quality is hardly degraded by lossy codec. The conversion from this format to the elemental image array is simple and does not depend on changes in the viewing distance and associated changes in camera number. Decoding and converting speeds are sufficiently high due to utilization of middleware based on
We have developed some prototypes of a one-dimensional integral imaging (1-D II) autostereoscopic display. Generally, II is one of the most promising methods for realizing an autostereoscopic display. However, a lens or barrier pitch is wide and obtrusive because this method requires many parallaxes. In this case, slanting lens or barrier is undesirable because the pattern is asymmetrical. From the result of examination about the display resolution of the autostereoscopic display, we adopted an LCD with mosaic color filter arrangement and a vertical lenticular sheet. We changed the color filter to the mosaic arrangement for two types of LCD. One was an LCD of 20.8-inch diagonal size with QUXGA resolution (3200 x 2400 pixels) and another was an LCD of 15.4-inch diagonal size with WUXGA resolution (1920 x 1200 pixels). The typical specifications of the prototypes of the autostereoscopic display were 32 parallaxes with 300 horizontal resolution for the 20.8-inch size and 18 parallaxes with the same resolution for the 15.4-inch size. We confirmed these prototypes showed good appearance and stereoscopic display properties due to the symmetrical lens pattern.
We propose a novel algorithm to maximize the viewing zone of integral 3-D imaging (II) display. In our algorithm, the elemental image array consists of two kinds of elemental images whose numbers of sub-pixels are N and (N+1). The pitch of exit pupils was set to be N times the width of the sub-pixel and an average width of elemental images was designed to exceed the pitch of the exit pupils to a small extent by distributing the elemental images consisting of (N+1) sub-pixels. Under this condition, all light rays generated from elemental images can be introduced to the viewing zone width (viewing width) on the viewing line at the distance L without converging points of light rays at around L. This algorithm was applied to one-dimensional II system with 32 parallax light rays using a 20.8”-QUXGA-LCD (192 ppi) equipped with a lenticular sheet. Then, the viewing width at 1.5 m was expanded to 500 mm, a value almost five times larger than the width of a conventional display system. Even if hardware configurations are fixed, our algorithm enables a viewing zone to be the maximum at a certain L.