We have proposed a quality of experience (QoE)-oriented wireless local area network (WLAN) to provide sufficient QoE to important application flows. Unlike ordinary IEEE 802.11 WLAN, the proposed QoE-oriented WLAN dynamically performs admission control with the aid of the prediction of a “loadable capacity” criterion. This paper proposes an algorithm for dynamic network reconfiguration by centralized control among multiple basic service sets (BSSs) of the QoE-oriented WLAN, in order to maximize the number of traffic flows whose QoE requirements can be satisfied. With the proposed dynamic reconfiguration mechanism, stations (STAs) can change access point (AP) to connect. The operating frequency channel of a BSS also can be changed. These controls are performed according to the current channel occupancy rate of each BSS and the required radio resources to satisfy the QoE requirement of the traffic flow that is not allowed to transmit its data by the admission control. The effectiveness of the proposed dynamic network reconfiguration is evaluated through indoor experiments with assuming two cases. One is a 14-node experiment with QoE-oriented WLAN only, and the other is a 50-node experiment where the ordinary IEEE 802.11 WLAN and the QoE-oriented WLAN coexist. The experiment confirms that the QoE-oriented WLAN can significantly increase the number of traffic flows that satisfy their QoE requirements, total utility of network, and QoE-satisfied throughput, which is the system throughput contributing to satisfy the QoE requirement of traffic flows. It is also revealed that the QoE-oriented WLAN can protect the traffic flows in the ordinary WLAN if the border of the loadable capacity is properly set even in the environment where the hidden terminal problem occurs.

We developed an 8.4-inch electrostatic-tactile touch display using a segmented-electrode array (30×20) as both tactile pixels and touch sensors. Each pixel can be excited independently so that the electrostatic-tactile touch display allows presenting real localized tactile textures in any shape. A driving scheme in which the tactile strength is independent of the grounding state of the human body by employing two-phased actuation was also proposed and demonstrated. Furthermore, tactile crosstalk was investigated to find it was due to the voltage fluctuation in the human body and it was diminished by applying the aforementioned driving scheme.

We propose a method to realize a subjective super-resolution on a high-speed LED display, which dynamically shows a set of four neighboring pixels on every LED pixel. We have experimentally confirmed the subjective super-resolution effect. This paper proposes a subjective super-resolution hypothesis in human visual system and reports simulation results with pseudo fixation eye movements.

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 utilized single-pixel imaging and deep-learning to solve the privacy-preserving problem in gesture recognition for interactive display. Silhouette images of hand gestures were acquired by use of a display panel as an illumination. Reconstructions of gesture images have been performed by numerical experiments on single-pixel imaging by changing the number of illumination mask patterns. For the training and the image restoration with deep learning, we prepared reconstructed data with 250 and 500 illuminations as datasets. For each of the 250 and 500 illuminations, we prepared 9000 datasets in which original images and reconstructed data were paired. Of these data, 8500 data were used for training a neural network (6800 data for training and 1700 data for validation), and 500 data were used to evaluate the accuracy of image restoration. Our neural network, based on U-net, was able to restore images close to the original images even from reconstructed data with greatly reduced number of illuminations, which is 1/40 of the single-pixel imaging without deep learning. Compared restoration accuracy between cases using shadowgraph (black on white background) and negative-positive reversed images (white on black background) as silhouette image, the accuracy of the restored image was lower for negative-positive-reversed images when the number of illuminations was small. Moreover, we found that the restoration accuracy decreased in the order of rock, scissor, and paper. Shadowgraph is suitable for gesture silhouette, and it is necessary to prepare training data and construct neural networks, to avoid the restoration accuracy between gestures when further reducing the number of illuminations.

We estimated the dependence of the perceived depth on luminance ratio by increasing the distance between the front and rear planes of a depth-fused 3-D (DFD) display. When the distance is great, the perceived depth has the tendency of nonlinear dependence on luminance ratio, which is very different from the almost linear dependence in a short-distance conventional DFD display. In a long-distance DFD display, the perceived depth is split to near the front plane at 0-40% of the rear luminance, near the rear plane at 70-100%, and the midpoint of the front and rear planes at 40-60%. Thus, the luminance-ratio dependence of perceived depth changes widely with the distance.

Three methods of presenting a three-dimensional (3-D) image – a real object, a protruding stereoscopic display, and the depth-fused 3-D (DFD) display – have different tendencies for the change in perceived depth produced when the visual acuity of the dominant eye is decreased by an occlusion foil. These different tendencies are estimated from the slope and correlation coefficient of the plot of perceived depth difference versus stimuli depth difference. This estimation was derived using the same experimental system setup composed of two displays and a half mirror for all three 3-D display methods. The perceived depth difference was measured for four subjects by calipers using two fingers. The slope and correlation coefficient had almost the same tendencies as follows. The real object had the smallest decrease among the three 3-D display methods when the dominant eye's visual acuity was decreased and the protruding stereoscopic display had the largest decrease. The DFD display method had an intermediate decrease between those of the real object and protruding stereoscopic display. When the dominant eye's visual acuity was high enough, the differences among the three 3-D display methods were small. When its visual acuity was decreased, the differences increased among the three 3-D display methods and became statistically significant.

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.

This paper reports on the relationships between the performance of retro-reflectors and the sharpness of an aerial image formed with aerial imaging by retro-reflection (AIRR). We have measured the retro-reflector divergence angle and evaluated aerial image sharpness by use of the contrast-transfer function. It is found that the divergence angle of the retro-reflected light is strongly related to the sharpness of the aerial image formed with AIRR.