A light field contains a large amount of data because it is represented as a dense set of multi-view images. We propose a method of compressing a light field as a newly emerging representation called a multiplane image (MPI), a graphics-oriented representation composed of a stack of semi-transparent images. Our method was constructed on a deep convolutional neural network (CNN), which was trained to generate an MPI from the given light field. To draw out the potential of this representation, we trained the CNN to be overfitted to the target light field. We also encouraged spatial smoothness to make the MPI easier to compress. Despite being in the early stage of development, our method has already achieved promising rate-distortion performance.

A multiplane image (MPI) is a useful 3-D representation composed of a stack of semi-transparent images, from which arbitrary views can be rendered with little computational cost. In this paper, we tackled the problem of super-resolution for MPIs, where a high-resolution MPI is inferred from a lower resolution one. By analyzing the anti-aliasing condition for the light field that would be produced from an MPI, we clarified that such a high-resolution MPI should have smaller sampling intervals over not only the spatial dimension but also the depth dimension. On the basis of this analysis, we constructed a learning-based method to transform a low-resolution MPI into a higher resolution one with depth resolution enhancement. Tested on BasicLFSR dataset, our method achieved 30.54 dB on average, which was 1.29 dB higher than the case without depth resolution enhancement. Visual results indicated that our method can accurately restore high-frequency components. Although super-resolution techniques have been studied extensively for images, videos, and light fields, this is the first work to address the problem of direct super-resolution for MPIs.

The multi-projection-based light-field display is a family of glasses-free three-dimensional(3-D) displays that is easy to scale up. We propose a method for creating a light-field display using a projector and kaleidoscope-like optics in this paper. Using optical simulations, we investigate how the kaleidoscope can adjust the display parameters. In addition, for a prototype system, we developed a semi-automatic calibration method. It has been established that a glasses-free 3-D display is possible with a small number of readily available parts and quite a simple structure.

A novel light field display based on time-division multiplexing is proposed. The display consists of a high-speed projector and a passive screen unlike conventional time-division multiplexing based methods. The high-speed projector projects monochrome images onto the screen while changing wavelength of a light source at high-speed. The screen has spectroscopic characteristics and delivers images toward different viewing points in horizontal direction corresponding to wavelength of projected images by chromatic dispersion. The proposed display is composed of a completely passive screen and only one projector, which is suitable for making a large display. We verified feasibility of the proposed display by experiments using a prototypes.

This paper proposes a method to reduce stereoscopic crosstalk in time-division multiplexing parallax barrier system with reduced power consumption, where a fine slit pattern is generated by projecting LED striped light bars through a lenticular lens. When LEDs and a lenticular lens are used to generate a slit pattern, crosstalk level becomes higher than that of the system using a pair of LCD panels because the LED backlight does not fully synchronize with the update of image in the LCD panel. To overcome this problem, the lighting time of LED light bars is shortened, which enables reduction of crosstalk without lowering the ratio of luminance to power consumption.

This paper presents a full-HD autostereoscopic display with a pair of monochrome and color panels based on time-division multiplexing parallax barrier. In the conventional system, usage of two color LCD panels with limited transmittance decreased the display luminance. In the proposed method, a monochrome panel is used in place of a color panel to generate an active barrier pattern, which is expected to increase transmittance. A prototype system is made, where moire is removed without using a diffuser. The maximum luminance given by the proposed method is measured and compared with that given by the conventional method. It is confirmed that the prototype system based on the proposed method has approximately 2.5 times higher luminance than the conventional system. It is also confirmed that the proposed method slightly decreases stereoscopic crosstalk, which is further reduced by widening the slit from 3 subpixels to 5 subpixels to alleviate diffraction.

Touch interfaces utilize mechanical vibration to give haptic feedback during operation. Lateral motion, that is, a vibration of the touch surface in the in-plane direction, is one of the methods used in haptic displays. Regarding lateral motion, we investigated the relationships between the displacement direction of the touch surface and the strength of the perceived stimulus. The targets for evaluation were perceived strength of stimuli in which the first-displacement directions of vibration were 0°, 90°, 180° and 270° against the proximal direction of the right index finger. A subjective evaluation was conducted and analyzed by using Scheffe's paired comparison method. It was shown that there was a statistically significant difference between the vibration group displaced in the long axis direction of the finger (0°, 180°) and that displaced in the short axis direction (90°, 270°). The result showed that the former was perceived to be stronger than the latter.

Mid-air images in a three-dimensional space beyond a screen enable users to observe virtual content without wearing any devices. When using a symmetrical mirror structure with dual slit-mirror arrays, the system enables the display of a large mid-air image by integrating multiple imaging paths. However, in the mirror design used in previous research, the luminance was discontinuous. In this study, we propose a novel tabletop system in which a tall mid-air image with continuous luminance is superimposed onto physical objects. Our proposed system, called “AIR-range”, presents mid-air images that appear seamlessly from the table surface to mid-air. By theorizing the relationship between the parameters of optical systems and luminance of mid-air images, we optimized the optical systems to minimize the difference in luminance between the imaging paths. The results of the comparison with the previous method showed an improvement in luminance continuity.

In this research, a subjective evaluation was conducted to compare the impressions of facial expressions presented by a light field display using the near virtual-image mode and a two-dimensional (2D) display. The goal is to investigate if a real-size three-dimensional image of a human face presented by the light field display has a larger influence on emotions and presents more lifelike face expressions than those presented by the 2D display. The impressions of using the light field display and the 2D display were compared using eight assessment criteria. The constantly changing facial emotions were exhibited on a flat-panel light field display with a screen size of 31.5 in. and a viewing-zone angle of 43.8°. The evaluation results showed that the light-field image had significantly higher evaluation values than the 2D image on the evaluation terms like "sense of affinity," "feeling like touching," "stereoscopic sensation," "fatigue," and "sense of being."

For Internet Protocol (IP)-based program-production systems, a flexible network can be deployed depending on the configuration. However, it is difficult for broadcast engineers to respond to problems because of this flexibility. We introduce an IP-based program-production-system monitoring tool for broadcast engineers. It visualizes transmission routes, throughput, packet loss, and other transmission states of an arbitrary signal from the results of analyzing signals on the network link and running status of network switches. It automatically verifies the transmission status of IP flows in conjunction with Networked Media Open Specifications control information. When verification fails, information related to the problems is presented to the broadcast engineers so that they can troubleshoot the IP-based program-production systems.