Yoshifumi Nagai

Analysis of Reproduced 3D Space by Stereoscopic Large LED Display

We have developed a stereoscopic large LED display with parallax barrier for use by the general public and stereoscopic cameras to show real world images in 3D. This paper aims to analyze stereoscopic camera separation and convergence angle to make the most use of a field of interest and the reproducible space provided by the large stereoscopic LED display. We describe the principle of a stereoscopic LED display with a parallax barrier and its reproducible space that is determined by the allowable range of disparity to fuse stereoscopic images. By using a model of stereoscopic imaging and display process, we introduce the formulas of the reproduced positions on our developed stereoscopic LED display. Furthermore, we analyze relationships between the stereoscopic camera separation, the convergence angle, the area of a field of interest, and the depth range of the reproduced space. The results show there are four categories in camera configurations: there are three kinds of camera configurations that have different characteristics and one configuration that is not recommended. Category A configuration reproduces a wide area of the field of interest in a long range of depth. Category B functions as a reduction of the field of interest. Category C functions as a magnification of the field of interest. In Category D, a narrow area of the field is reproduced in a short range of depth. In particular, for use by stereoscopic LED display with a rather low resolution, Category A and Category C are recommended because they fully use the reproducible positions.

Reduction of the thickness of lenticular stereoscopic display using full-color LED panel

The goals of our research are to realize stereoscopic large displays for the general public in the open air. These goals impose certain design constraints. It is preferable to view stereoscopic images without any special glasses. Multiple viewing areas are necessary to crowds of viewers. The thickness of the stereoscopic large display is a problem for installations. We have developed a stereoscopic full color LED display using parallax barrier and demonstrated multiple viewing areas. However, the thickness of that stereoscopic display, which is consisted of 8-mm pitch LED panel, becomes over 2 min the case that the viewing distance is designed for 20 m. In order to reduce the thickness of stereoscopic LED display, we propose use of dual lenticular sheets. The first lenticular sheet performs multiple imaging, which allows multiple viewing areas without diffusion screen. The second lenticular sheets separates the raster images into the right and left eye positions. The thickness, which is defined as the distance between the LED panel and the second lenticular sheet, can be reduced below 50cm for the viewing distance of 20 m. Optimal parameters are discussed to reduce the thickness.