Our goal is to realize an extra-large stereoscopic display in the open air for use by the general public. We have developed a stereoscopic large display by use of a full-color LED panel. Although the developed display enables viewers to view the stereoscopic images without any special glasses, it is necessary for the viewers to move to stand within the viewing areas. Movements of the viewers are considered to depend on arrangements of viewing areas. The purpose of this paper is to investigate the movements of viewers who watch different designs of stereoscopic LED displays with a parallax barrier, including conventional designs to provide multiple perspective images and designs to eliminate pseudoscopic viewing areas, and evaluate the performance of different viewing areas based on the obtained paths of the viewers. We have developed a real-time measurement system of a viewer's position by use of a camera on the ceiling. We have recorded the viewing movements caused by the shift of viewing areas. It was found that the viewers moved to stand on orthoscopic viewing positions. The movements of viewers who move to find a viewing area have been recorded with different designs of stereoscopic LED displays that provide different viewing areas. We have calculated the lateral moving time of the viewers'movements. It is shown that the elimination of pseudoscopic viewing areas reduces the lateral moving time. Thus, the real-time measurement system of a viewer's position has been utilized for evaluation of performance of the different designs of stereoscopic LED displays.

By using full-color light emitting diode (LED) panel, we have been studying a stereoscopic full-color large television in broad daylight. In order to implement stereoscopic large display for the general public, optimum parameters of display elements and parallax barrier and viewing areas of stereoscopic display using parallax barrier are discussed. Although stereoscopic display with parallax barrier permits the viewer to view stereoscopic images without any special glasses, its viewing area is restricted by crosstalk and disappearing of pixels. Enlarged viewing areas, which are derived from the small ratio of light emitting region to pixel and a proper aperture ratio of parallax barrier, are analyzed. A model of a viewer standing toward the display is proposed because the viewer apart from the horizontal center of the display turns to the center point of LED display and this turning causes a deviation of viewer's eye position. Then, the allowable number of viewing locations is derived on "no crosstalk" and "no disappearance" conditions. The optimum aperture ratio of parallax barrier and the width of light emitting region is obtained through the optimization. The viewing area obtained from the analysis is confirmed by experiments using full-color LED panel. Relations between viewing area and the moire fringes is also discussed. The depth of the viewing area agrees the viewing distance where no moire fringe appears. Furthermore, possibility of display for the crowds is discussed.

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.