In this paper, we focused a multi-layer structure in which the LC layers are divided by LC-polymer films to stabilize the alignment of thick LC used in LC reflect arrays and to achieve a fast response time. We also fabricated LC-polymer films that divides the LC layers and evaluated its alignment state. As a result, it was revealed that the LC-polymer film has the ability to align the LC. This is expected to stabilize the alignment of the thick LC and speed up the response time.
A new internal compensation method for OLED display with high mobility oxide TFT is presented. The differential offset method was devised to make an offset voltage adapted for each pixel utilizing the behavior of the source follower type circuit. It can preemptively eliminate not only the sensing error but also Vth dependent voltage errors including after-sensing steps. Fabricated 5.5-in. QHD OLED displays have showed improved uniformity.
In ultra-high-definition active-matrix organic light-emitting diode (AMOLED) displays, the external compensation technique improves burn-in and uneven luminescence by varying the current through the driving thin-film transistors (TFTs). However, sensing the current through the driving TFT for every pixel is time-consuming because of the increased number of scanning lines. Hence, in this study, we propose a method to reduce the number of measurements and shorten the measurement time by interpolating from the current measurement data for surrounding pixels. We show that this method can be applied to a 4K flexible AMOLED display and can satisfactorily compensate degradation due to burn-in.
In the display device employing the pulse width modulation (PWM) method for expressing grayscale, visual artifacts such as distortion, ghost, and color breakup appear when an image moves and observer's eye tracks the image. This paper clarifies a mechanism of moving image degradation with various PWM methods. With the PWM, the distribution of light emission within a display field time vary according to the gray levels. The variation of temporal center of light emission is transformed into spatial shift of image. When there are two non-overlapping period in the temporal light emission pattern of adjacent objects, ghost appears. The difference in the temporal distribution of light emission of color sub-pixels causes color breakup. Shape distortion and color breakup severely degrade the moving image quality when the standard left-aligned PWM is employed. The center-aligned PWM generates unacceptable ghosting. Pulse frequency modulation produces the same image quality as the pulse amplitude modulation.
In this study, we introduce the concept of driver vision support using pixelated headlights with imperceptive pattern illumination for automotive lighting. Our lighting technique improves the visibility of the driver without harming the sight of pedestrians and oncoming vehicles. In addition, we introduce a simultaneous and separate information service concept for pedestrians and drivers with pixelated headlights. We also present an alignment error-correction method for projections from a continuously moving vehicle.
3D displays and interactive technology play an important role in the Metaverse. This paper addresses and analyzes 3D display and depth sensing technologies applied in the Metaverse. Combining key 2D to 3D conversion algorithms, depth information reconstruction technology which is based on structured light and time of flight technology, realizes the 3D vision of the Metaverse. At the same time, it introduces 3D interactive technologies in detail. Through single-lens interactive technology, dual-lens interactive technology and depth camera interactive technology, it explains the 3D interaction way of the Metaverse. The forward-looking 3D display and interactive technology, will be able to realize a more perfect Metaverse world. We hope the coming of the Metaverse Era will create a better future.
In mission-critical systems such as session control servers provided by telecommunications carriers, we are researching distributed cluster architectures that enable flexible control of system performance. Data must be maintained even in the event of a disaster. Considering the physical distance between the servers that manage the original and duplicate data respectively, we proposed a data redundancy control method that does not cause data loss even in the event of a large-scale disaster. The proposed method was evaluated by computer simulation. We also proposed an implementation of the data loss avoidance method in Apache Cassandra that defines “Racks” as a “site”. We implemented the method and confirmed that site collision avoidance was achieved without data loss even in the case of a large-scale disaster. We found that the number of servers in each site should be about the same for optimal data storage in terms of decentralization and reliability.
C programming is taught in introductory programming courses in many universities across the world. To assist self-studies of novice students, we have developed C programming learning assistant system (CPLAS). In this paper, we study the grammar-concept understanding problem (GUP) in CPLAS for first-step studies of understanding grammar concepts in C programming. Each question describes the definition of a keyword in a source code and requests to answer it. Any answer is verified through string matching. If a student cannot answer questions, he/she does not understand basic concepts and may be lost in C programming study. For GUP, we selected 66 keywords with questions, and generated 35 instances that cover them. The assignment results to 130 undergraduate students in Okayama and Nihon Universities revealed the difficult keywords and learning progresses of students.
This paper discusses a side-lobe power reduction technique using window functions and a performance improvement scheme for use in windowed Orthogonal Frequency Division Multiplexing (OFDM) systems to enhance their spectrum usage. The windowed OFDM approach is effective for suppression of out-of-band emission. However, the communication performance using this method is degraded when compared with conventional schemes. To improve the performance of windowed OFDM in frequency-selective fading channels, a pre-coding method using a unitary transform is utilized. Furthermore, an additional coding scheme using pseudo-random code is proposed to improve its overall communication performance. The BER performance can be improved when compared with the conventional schemes, because the proposed coding scheme can reduce the noise variance in the demodulation process for the pre-coded windowed OFDM. The out-of-band emission power can be reduced and the notch depth can be increased when using the proposed scheme.
In this paper, we develop an automatic image sonification system using auditory icons and their stereophonic presentation. We evaluated the effects of scene sounds and action sounds on the understanding of the scene and the sense of presence. The results showed that the scene sounds contributed to the understanding of the scene and the sense of presence and that action sounds also improved the sense of presence. On the other hand, it was confirmed that object sounds alone can convey scene information in images and have a high index of sense of presence. Our sonification system is expected to provide not only a more immersive experience for sighted people through images but also an opportunity for people with visual impairments to share the experience through social networking services (SNSs).
In content sharing with Peer-to-Peer (P2P) network systems, content has been smoothly acquired and prevented from being lost by replication of the content and deploying replicas on multiple peers. However, in some conventional methods, it takes a long time for the replicas of content to be spread over the network, which makes stable content sharing difficult. In this paper, we propose a method to predict the change in popularity of each content item over time and to deploy an appropriate number of replicas of popular content evenly on the network before the supply becomes insufficient. The method also keeps the ratio of each content replica's total stored capacity to the whole storage capacity in P2P in proportion to its demand, while considering each replica's size of capacity. Furthermore, we confirm the effectiveness of the proposed method by computer simulations.
In this paper, two types of 4.0 μm back side illuminated stacked voltage mode global shutter pixels implemented in a prototype CMOS image sensor are reported. One is a pixel with a lateral overflow integration capacitor (LOFIC) to expand the sensor dynamic range and the other is a pixel having dual photodiodes and dual conversion gains which enables the phase detection auto focus capability with single exposure high dynamic range (SEHDR). Thanks to the LOFIC and the dual conversion gain technologies, SEHDR of 90 dB and 77 dB has been achieved in the global shutter mode.
There has been a steady increase in the use of internet protocol (IP) technology for live professional media production. In addition, development is proceeding on remote production of live programs by connecting venues and a broadcasting station via an IP network. The devices needed for this remote production are being developed as well. So far, dedicated devices for transmitting 2K, 4 K, and 8K signals have been used in live professional media production, which has led to increasingly complex production systems. We propose a multiformat transmission system that enables efficient remote production without the need for dedicated devices. The proposed method decomposes 4K and 8K videos into 2K videos in order to treat 2K, 4K, and 8K video signals in a unified format. We report a simulation that evaluated image quality of the video decomposition method and a lightweight compression and evaluated the video decomposition processing delay.