In this paper, we proposed a new device structure using plastic microtubes to realize robust flexible liquid crystal (LC) devices. This device is formed by lining up large number of plastic microtubes, filled with LC, and placing transparent electrodes on the top and bottom. We fabricated the device using the tube bonding technique and demonstrated that a uniform initial alignment can be obtained in the microtubes. We also found that light modulation by vertical electric field drive is possible and that the display characteristics are not disturbed even when high external pressure is applied. This device leads to the realization of flexible LCDs with high durability.

We propose a method to improve the decay response time of polymer network thick-film liquid crystal devices used in reflectarrays for millimeter-wave applications while suppressing the increase in drive voltage. We have shown that the fast decay response controllable at 30 V in conventional thin-film transistors can be achieved in thick-film liquid crystals by heat treatment after or during UV exposure. The fastest device had a decay response time of less than 1/42 compared to a thick-film liquid crystal-only device.

Pixel structures smaller than 1 μm are required for the practical application of electronic holography displays. 1 μm pitch pixel structures are greatly affected by the propagation of elastic forces of liquid crystals, and polymer wall structures are indispensable. In addition, the design of spatial light modulators must consider the difficulty of driving with high voltages due to the miniaturization of driving transistors. In this study, the optimal design parameters for spatial light modulators, such as the substrate surface anchoring strengths and the polymer wall, were clarified to achieve high resolution, low voltage drive, and high light utilization efficiency.

This study proposes liquid-crystal (LC) lenses that are adaptive to oblique incidence to achieve planar microtracking concentration for sunlight. In particular, we designed the LC alignment and device structure for oblique incidence. Numerical simulations and experiments were conducted to analyze the diffracted light. The obtained results confirm that the designed device structure focused the light along a single plane.

It has been pointed out that the widening of the color gamut in displays increases discrepancies in color appearance among observers due to observer metamerism. This is attributed to the interaction between the narrow emission spectrum of wide color gamut displays and the fact that even observers with normal color vision have variability in color vision and differ from the CIE standard observer. To aid in understanding the variability in color appearance, we propose a method to simulate color appearance using individual color matching functions and the spectral power distributions of displays. The observer variability can be visually recognized by comparing the original and simulated image on the same display. In addition, the differences can be quantitatively evaluated by calculating the color difference between them. The simulated images clearly demonstrated an increase in inter-observer variability with wider color gamuts, and a greater magnitude of color differences at the lower saturation levels.

We conducted sensory tests for visibility of blurred-virtual characters and colored-virtual characters. And we analyzed their effect on visibility to investigate the way to improve the visibility for AR display. We changed blur/color situation of virtual characters in periphery of gaze position (gaze-peripherychange AR) and changed blur/color situation of virtual characters at the gaze position (gaze-position-change AR). As a result, there were differences in results between the blurred-virtual characters and colored-virtual characters. Regarding blurred-virtual characters, the results showed that response times of gaze-peripherychange AR (blur) were shorter in response time analysis and gaze-position-change AR (blur) got higher evaluation from subjects in questionnaire analysis. Regarding colored-virtual characters, the results didn't show the major trends, but there was a significant difference that shows response time of gaze-position-change AR (color) is shorter.

Realization of an electronic holographic display with a wide viewing angle requires a spatial light modulator with a small pixel pitch. When the pixel pitch becomes small, phase distortion due to electric field leakage from neighboring pixels and elastic forces becomes large, and the simple simulations used so far cannot calculate the actual phase irregularity. In this study, we compared the phase effects of spatial light modulators with small pixel pitch on neighboring pixels by using multiple simulations.

This study focuses on the development of a sensor-integrated biological model and simulator to aid in the acquisition of oral care techniques for preventing aspiration pneumonia. The system specifically targets tongue cleaning, an area where simulator development remains largely unexplored. To address this gap, a tongue-shaped elastic tactile sensor array was proposed, enabling real-time feedback during practice. A flexible sensor-display integrated device was developed using a conductive elastomer-based pressure detection mechanism. The sensor array successfully detected pressure within the expected range. Subsequently, a simulation system was implemented, allowing users to practice tongue cleaning with real-time pressure feedback, tongue condition visualization, and performance evaluation. Data collected from academic conferences and care facilities confirmed the simulator's effectiveness in skill enhancement, although challenges remain in accurately replicating tongue softness. To overcome this limitation, a novel conceptual tongue structure that balances softness and sensitivity was proposed, and its characteristics were evaluated and validated.

Silver nanoparticles (AgNPs) can exhibit various chromatic colorations depending on their morphology. This study utilized a derivative of ethylenediaminetetraacetic acid (EDTA) to control the electrodeposited morphology of AgNPs in an Ag deposition-based electrochromic (EC) device. Because the carboxyl groups of the EDTA derivative were electrochemically reduced to radical anion and worked as an electrochemical mediator, the deposition of AgNPs was promoted. As a result, the morphology of deposited AgNPs formed an anisotropic shape, such as a rod or needle, due to the mediation effect of the EDTA derivative. Moreover, the EC device with EDTA derivative exhibited a deep black state since AgNPs were formed as porous structures, inducing multiple scattering. Consequently, a black state on a flat electrode with less than 20% reflection was achieved without the ITO nanoparticles-modified electrode.

In recent years, drone delivery has been sought as an alternative to truck transportation, and optical wireless power transfer (OWPT) has attracted attention to achieve sufficient flight range. For the practical implementation of OWPT, two requirements must be addressed: the apparent size reduction of the target solar cell due to its position and the need to concentrate light to improve power transfer efficiency. Based on these requirements, we propose an optical receiver system that utilizes a spherical lens and radially extending light guides connected to its focal point. In this study, we evaluate this receiver using ray-tracing simulations and identify the parameters that determine its optimal shape.

We reduced the electrode pitch to 0.7 μm and drove the ferroelectric liquid crystal (FLC) at a low voltage of 1 V to realize a spatial light modulator (SLM) with small pixels for a holographic display with a wide viewing zone angle. Even with an extremely small electrode pitch of 0.7 μm, the FLC could be driven at a low voltage of 1 V. We also evaluated the switching angle and response time of the FLC on the fine-pitch electrodes and found that the switching angle decreases and the response time increases when the electrode pitch is reduced. This work shows the possibility of applying the SLM using the FLC to a holographic display with a wide viewing zone angle.

This paper provides an overview of supervised and self-supervised image denoising techniques, including discussions on practical usages. Through the development of deep network architectures, training strategies, and datasets, supervised deep learning methods outperformed traditional non-learning approaches by substantial margins. However, creating well-registered, real-world noisy-clean image pairs for training is challenging, and thus, there is a limited number of practical training images. Additionally, a denoiser trained with a specific dataset may not perform well for images with different properties. Consequently, there is a growing demand for self-supervised training methods that do not rely on external training sets. In this paper, we first present an overview of supervised techniques and training datasets. We then explore self-supervised methods that effectively remove noise without the need for external datasets and discuss potential future directions for this field. We conclude the paper with a comparison between supervised and self-supervised methods, their selections, and future studies.

We propose a customizable, automated cheering system that enhances fan experiences during live performances through sound-based communication in the audible band. The system operates in the 17–18.8 kHz frequency range, which is minimally perceived by the human ear. A chirp signal, known for its robustness against noise, is used to transmit index data and is additively embedded into the music. Receiver devices detect the chirp signal using correlation analysis, achieving synchronization with the performance. Based on the received 7-bit index data, the system automatically selects and displays the corresponding pre-configured idol cheering screen from a set of 128 messages in real-time.

Large (200 × 200 mm) electrochromic (EC) devices were fabricated using Fe(II)-based metallosupramolecular polymer (MSP) as the EC material, nickel hexacyanoferrate (NiHCF) as the counter electrode material, and LiClO₄ solution as the electrolyte. The fabricated EC devices were installed in a southfacing window of a high-rise building in the Ibaraki Prefectural Government Office. After about one year of practical use, a reversible color change between purple and colorless was confirmed on the EC smart window, suggesting the high durability of the EC device. The fading of the Ibaraki device in the colored state was confirmed by a higher transmittance (12%) than the standard reference (STD) device (3%). The STD device exhibited 57% optical contrast at 580 nm between +1.5 and 0 V, while the Ibaraki device maintained 66% between +3.0 and 0 V.

This study proposes an effective handcrafted algorithm of product region extraction, which identifies product regions at image pixel level from images uploaded to consumer-to-consumer online marketplaces. The proposed method applies graph cuts to classify the image pixels and patches as either product or background regions. A comparative experiment using 425 product images demonstrated that the proposed method significantly improved the F-measure by at least 1.83% compared to a conventional method, with at least 0.13% and 2.16% of increase in precision and recall, respectively. In addition, the proposed method achieved the F-measure comparable to that of a supervised segmentation using deep neural networks, which were trained on 641 product images. Further comparisons and discussions in this paper provide a detailed evaluation of the effectiveness of the proposed method.

This study proposes a few-shot personalized saliency prediction method that leverages interpersonal gaze patterns. Unlike general saliency maps, personalized saliency maps (PSMs) capture individual visual attention and provide insights into individual visual preferences. However, predicting PSMs is challenging because of the complexity of gaze patterns and the difficulty of collecting extensive eye-tracking data from individuals. An effective strategy for predicting PSMs from limited data is the use of eye-tracking data from other persons. To efficiently handle the PSMs of other persons, this study focuses on the selection of images to acquire eye-tracking data and the preservation of the structural information of PSMs. In the proposed method, these images are selected such that they bring more diverse gaze patterns to persons, and structural information is preserved using tensor-based regression. The experimental results demonstrate that these two factors are beneficial for few-shot PSM prediction.

In conventional instruction for beginning soccer players, the instructor often teaches by demonstration and feeling, making it difficult for the learner to grasp the proper posture correctly and understand how to improve their own instance. In this study, we introduce and investigate two types of visual augmentation for soccer kicking posture instruction: Spot projection directly on the ball surface and on the ground for guiding foot positions, and Portrait playback providing skeletal motion in the scene at free point of view. Both augmentations can also display shadow instruction from an expert simultaneously. We conducted a user study (N = 48) to verify how the two types of augmentation would affect the soccer learners in the learning process. The results showed that Spot Projection could help to understand the posture of the axis leg, while Portrait Playback could help to understand the example of the upper body and leg movements.

In Wide-Area Projection with multiple projectors, the existence of Non-Projected Areas (NPAs) inside the image projection area preset on a wall surface significantly degrades immersive experience. Therefore, we propose a novel method to certainly obtain the optimal multi-projector arrangements so that NPAs are excluded completely, that is, the image projection area is entirely covered. In detail, the proposed method includes A) the method to determine feasibility (whether NPAs exist or not) by identifying intersections of polygonal boundaries, and B) the method to compute an initial feasible solution (an arrangement with no NPAs) by minimizing Non-Projection Ratio (NPR). Furthermore, we experimentally confirmed that all optimal solutions computed by the proposed method were feasible.