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We review the progress in multiplexed single-photon sources, including overviews on heralded single-photon sources and photon-number-resolving detectors, the various approaches to multiplexing, and their successful experimental realizations. We also summarize the recent results on the theoretical description and optimization of multiplexed single-photon sources, focusing on the procedures and methods that enable the improvement of the performance of these sources. [ABSTRACT FROM AUTHOR]

We review the progress in multiplexed single-photon sources, including overviews on heralded single-photon sources and photon-number-resolving detectors, the various approaches to multiplexing, and their successful experimental realizations. We also summarize the recent results on the theoretical description and optimization of multiplexed single-photon sources, focusing on the procedures and methods that enable the improvement of the performance of these sources.

Three-dimensional displays are receiving considerable attention owing to their ability to deliver realistic content. Particularly, a multiview display with temporal multiplexing offers advantages in terms of fewer restrictions for optical alignment and flexibility in forming view density. However, most of studies realize horizontal parallax-only multiview display. In a horizontal parallax-only multiview display the content is distorted in the vertical direction as the observer changes the viewing distance. It is helpful to understand this phenomenon using the Wigner distribution function (WDF). In this study, we divided the viewing zone (VZ) into the sub-viewing zone and integrated viewing zone according to the number of views of the observer. Specifically, the changes in the contents are experimentally evaluated at different viewing distances to validate our expectation. For the experiment, we implemented a full-parallax multiview display with spherical symmetry and designed a high-speed wide-angle dual-axis scanner. This scanner comprises two single-axis scanners connected by high numerical-aperture scanning optics. The proposed system and WDF analysis of VZ will be helpful to evaluate the characteristics of the multiview system. [ABSTRACT FROM AUTHOR]

Three-dimensional displays are receiving considerable attention owing to their ability to deliver realistic content. Particularly, a multiview display with temporal multiplexing offers advantages in terms of fewer restrictions for optical alignment and flexibility in forming view density. However, most of studies realize horizontal parallax-only multiview display. In a horizontal parallax-only multiview display the content is distorted in the vertical direction as the observer changes the viewing distance. It is helpful to understand this phenomenon using the Wigner distribution function (WDF). In this study, we divided the viewing zone (VZ) into the sub-viewing zone and integrated viewing zone according to the number of views of the observer. Specifically, the changes in the contents are experimentally evaluated at different viewing distances to validate our expectation. For the experiment, we implemented a full-parallax multiview display with spherical symmetry and designed a high-speed wide-angle dual-axis scanner. This scanner comprises two single-axis scanners connected by high numerical-aperture scanning optics. The proposed system and WDF analysis of VZ will be helpful to evaluate the characteristics of the multiview system.

Holographic displays give users a realistic experience by allowing them to perceive three‐dimensional (3D) images without any visual aids such as glasses. However, in a holographic display using liquid crystal based spatia/light modulator (LC‐SLM), the pixel pitch is not small enough so that the images are realized in limited areas. In addition, the slow framerate of LC‐SLM makes temporal multiplexing practically impossible. We propose holographic display using digital micromirror device (DMD) and apply temporal multiplexing method. The proposed system enhances viewing angle through temporally switched directional illuminations. Besides, the DMD's sufficient framerate provides significant reduction in speckle noise of holograms. We experimentally show the feasibility of proposed method by reconstructing holograms of 3D objects. [ABSTRACT FROM AUTHOR]

Rendering in virtual reality (VR) requires substantial computational power to generate 90 frames per second at high resolution with good-quality antialiasing. The video data sent to a VR headset requires high bandwidth, achievable only on dedicated links. In this paper we explain how rendering requirements and transmission bandwidth can be reduced using a conceptually simple technique that integrates well with existing rendering pipelines. Every even-numbered frame is rendered at a lower resolution, and every odd-numbered frame is kept at high resolution but is modified in order to compensate for the previous loss of high spatial frequencies. When the frames are seen at a high frame rate, they are fused and perceived as high-resolution and high-frame-rate animation. The technique relies on the limited ability of the visual system to perceive high spatio-temporal frequencies. Despite its conceptual simplicity, correct execution of the technique requires a number of non-trivial steps: display photometric temporal response must be modeled, flicker and motion artifacts must be avoided, and the generated signal must not exceed the dynamic range of the display. Our experiments, performed on a high-frame-rate LCD monitor and OLED-based VR headsets, explore the parameter space of the proposed technique and demonstrate that its perceived quality is indistinguishable from full-resolution rendering. The technique is an attractive alternative to reprojection and resolution reduction of all frames. [ABSTRACT FROM AUTHOR]

Specifically conceived for applications related to face analytics and tracking, scene segmentation, hand/finger tracking, gaming, augmented reality, and RGB-D cameras are nowadays used even as 3-D scanners. Despite depth cameras’ accuracy and precision are not comparable with professional 3-D scanners, they still constitute a promising device for reverse engineering (RE) applications in the close range, due to their low cost. This is particularly true for more recent devices, such as, for instance, the RealSense SR300, which promises to be among the best performing close range depth cameras in the market. Given the potentiality of this new device, and since to date a deep investigation on its performances has not been assessed in scientific literature, the main aim of this paper is to characterize and to provide metrological considerations on the Intel RealSense SR300 depth sensor when this is used as a 3-D scanner. To this end, the device sensor performances are first assessed by applying the existing normative guidelines (i.e. the one published by the Association of German Engineers - Verein Deutscher Ingenieure - VDI/VDE 2634) both to a set of raw captured depth data and to a set acquired with optimized setting of the camera. Then, further assessment of the device performances is carried out by applying some strategies proposed in the literature using optimized sensor setting, to reproduce “real life” conditions for the use as a 3-D scanner. Finally, the performance of the device is critically compared against the performance of latest short-range sensors, thus providing a useful guide, for researchers and practitioners, in an informed choice of the optimal device for their own RE application. [ABSTRACT FROM PUBLISHER]

An autostereoscopic display system which can allow multiple users to see 3D perception of the images without loss of resolution is introduced in this paper. It is a kind of time-sequential 3D systems incorporating eye tracking and directional optical design to realize free viewing. The whole system consists of five main parts: multi-user eye tracker, direct-view LCD, steerable LED array, MCU controller, and a suit of directional optics. It employs the theory of temporal multiplexing by the use of a LCD available to run at 120 Hz and utilizes a multi-user eye tracker to get the viewers' eye positions so as to control the steerable backlight to produce multiple pairs of exit pupils to the viewers' eyes. This paper describes the detailed structure of the system, the operation principle and the results obtained are also described. This approach differs from many existing ones in that it is switchable between 2D and 3D mode both with full resolution and is much thinner compared to other bulky systems with a width less than 20 cm. [ABSTRACT FROM PUBLISHER]

Large screen Organic Light Emitting Diode (OLED) technology is finally emerging as a technology ready for consumer use. OLED has a number of areas in which it can in principle be better than Liquid Crystal Displays (LCDs); two ways in particular are that OLED technology can achieve black levels that are much darker than LCDs, and the OLED pixels can switch extremely rapidly. These differences can permit OLED displays to outperform LCD under a number of conventional scenarios, but it can also enable some dramatically improved stereoscopic 3D (s3D) displays, including full-resolution temporal multiplexing with more than two views. In this paper, we review a set of experiments evaluating the strengths and weaknesses of OLED technology in general with a particular emphasis on understanding how the strengths of OLED technology can be leveraged to maximize the performance of an s3D display system. [ABSTRACT FROM AUTHOR]