Underwater polarization‐based single pixel imaging

This paper extends single pixel imaging (SPI) to underwater scenario. Backscattering, which is a limiting factor for underwater imaging, is analyzed for the SPI, and the forward model of SPI under backscattering is formulated. Inspired by the polarization‐based descattering technique, we propose the two cross‐polarization SPI detection scheme to eliminate the backscattering light. The descattered image is reconstructed from the cross‐polarization data. Experimentally, we construct the underwater polarization‐based single‐pixel imaging system. And we test our scheme under different turbidity water. It is shown in experiments that our method can provide a clear image at turbid water of 32FTU, where the classical SPI has been severely contaminated by the backscattering, even under the best the polarization state.     

The new route for realization of 1‐μm‐pixel‐pitch high‐resolution displays

A new pixel structure for the realization of a 1‐μm‐pixel‐pitch display was developed. This structure, named vertically stacked thin‐film transistor (VST), was based on the conventional back‐channel etched thin‐film transistor (TFT), but all the layers except the horizontal gate line were vertically stacked on the embedded data line, enabling the implementation of high‐resolution display panels. The VST device with a channel length of 1 μm showed a high field effect mobility of more than 50 cm²/Vs and low subthreshold slope of 78 mV per decade. It also shows a high uniform electrical characteristic over the entire 6‐in. wafer. The development of a new pixel architecture is expected to enable the implementation of 1‐μm‐pixel‐pitch high‐resolution displays such as spatial light modulators for digital holograms.     

注入式红外成像仿真系统设计

根据红外成像系统的仿真试验需求,设计并实现了一套128像素×128像素的注入式红外成像仿真系统。详细介绍了注入式红外成像仿真系统的设计方案,论述了硬件系统的关键技术和实现方法,介绍了软件实现方案和系统调试方法。试验测试结果表明,模拟图像的帧频达到100 Hz,单元像素的灰度分辨率为16-bit,精度达14-bit。经实际使用表明此系统满足设计指标要求。     

An AMOLED pixel circuit for high image quality of 1000 ppi mobile displays in AR and VR applications

In this paper, an active‐matrix organic light‐emitting diode pixel circuit is proposed to improve the image quality of 5.87‐in. mobile displays with 1000 ppi resolution in augmented and virtual reality applications. The proposed pixel circuit consisting of three thin‐film transistors (TFTs) and two capacitors (3T2C) employs a simultaneous emission driving method to reduce the number of TFTs and the emission current error caused by variations in threshold voltage (Vth) and subthreshold slope (SS) of the low‐temperature polycrystalline silicon TFTs. Using the simultaneous emission driving method, the compensation time is increased to 90 μs from 6.5 μs achieved in the conventional six TFTs and one capacitor (6T1C) pixel circuit. Consequently, the emission current error of the proposed 3T2C pixel circuit was reduced to ±3 least significant bit (LSB) from ±12 LSB at the 32nd gray level when the variations in both the Vth and SS are ±4σ. Moreover, both the crosstalk errors due to the parasitic capacitances between the adjacent pixel circuits and due to the leakage current were achieved to be less than ±1 LSB over the entire gray level. Therefore, the proposed pixel circuit is very suitable for active‐matrix organic light‐emitting diode displays requiring high image quality.     

Invited Paper: Super Hi‐Vision projection display for next‐generation TV

Abstract— For future broadcasting, NHK is studying new video services offering very‐high‐picture quality achieved through Super Hi‐Vision. Toward that aim, a projection display that has a resolution equivalent to 7680 × 4320 pixels by using four 4096 × 2160 D‐ILA? panels has been developed. The display requires precise convergence adjustment because it consists of two projection units, so an automatic adjustment system was developed. Although the pixel number of the digital camera used is less than that of the display, a 0.2‐pixel accuracy was obtained. This report introduces theaters that use this display as an example of applying the Super Hi‐Vision video system.     

4032 ppi High‐resolution OLED microdisplay

A 0.5‐inch Ultra Extended Graphics Array (UXGA) organic light‐emitting diodes microdisplay has been developed with 6.3 μm pixel pitch. Not only 4032 ppi high resolution but high frame rate, low power consumption, wide viewing angle, and high luminance have been achieved. This newly developed organic light‐emitting diodes microdisplay is suitable for Near‐to‐Eye display applications, especially electronic viewfinders.     

Critical point defect detection for small‐pixel thin‐film transistor array applied to medical display

Thin‐film transistor (TFT) array testing technique has been used, which provides defect detection capability to control the yield of the TFT process. In the past, several defect inspection technologies have been developed and applied for the TFT array testing. When the TFT array pixel size is getting smaller and the resolution is higher, they also encounter the performance limitation on detecting the critical defect in this small‐pixel TFT array and facing a limited testing requirement. For medical display applications, the display pixels on an array panel are getting smaller and smaller; therefore, defect detection is getting more important and critical for managing yield with quality. In this study, a novel approach for defect detection was proposed. Here, the proposed voltage imaging technique is used for the TFT array test, and it provides better small‐pixel TFT array defect detection capability. The experimental results show that by using the voltage imaging technique, detecting critical point defect of TFT array can be effectively improved. And the detected small‐pixel size of TFT array panels can be smaller than 55 µm of an advanced medical display.     

A novel pixel memory using integrated voltage‐loss‐compensation (VLC) circuit for ultra‐low‐power TFT‐LCDs

Abstract— A novel pixel memory using an integrated voltage‐loss‐compensation (VLC) circuit has been proposed for ultra‐low‐power TFT‐LCDs, which can increase the number of gray‐scale levels for a single subpixel using an analog voltage gray‐scale technique. The new pixel with a VLC circuit is integrated under a small reflective electrode in a high‐transmissive aperture‐ratio (39%) 3.17‐in. HVGA transflective panel by using a standard low‐temperature‐polysilicon process based on 1.5‐μm rules. No additional process steps are required. The VLC circuit in each pixel enables simultaneous refresh with a very small change in voltage, resulting in a two‐orders‐of‐magnitude reduction in circuit power for a 64‐color image display. The advanced transflective TFT‐LCD using the newly proposed pixel can display high‐quality multi‐color images anytime and anywhere, due to its low power consumption and good outdoor readability.     

Novel voltage programming n-channel TFT pixel circuit for low power and high performance AMOLED displays

This paper proposes a novel pixel circuit for high resolution, high frame rate, and low power AMOLED displays that is implemented with one driving n-channel TFT, six switching n-channel poly-Si TFTs, and a storage capacitor. The proposed pixel circuit adopts the voltage programming scheme for threshold voltage compensation. Because the whole line time is in use only for charging the data voltage, this pixel circuit is applicable to high resolution and frame rate displays. In addition, it compensates voltage variation of OLEDs and voltage drop of supply lines at lower power consumption. On the average, the non-uniformity of a proposed circuit is reduced to 2.5%, compared to 7.1% of the previous one at a 240 Hz full-HD display. On the other hand, the compensation voltage error, which is caused by feed-through and charge injection noises from falling control signals of switching TFTs, is much less in the proposed scheme than in the previous 5T2C structure. The average error of the proposed circuit is reduced to 0.18 V, compared to 0.75 V of the previous one. The initialization power consumption of the 7T1C circuit is reduced to 98 mW, compared to 530 mW of the 5T2C circuit and the average dynamic power saving ratio of data drivers is estimated in the 7T1C pixel as 98.7% over the 5T2C one for 24 test images.     

一种高分辨率视频切换矩阵研究与设计

传统的视频切换矩阵带宽低,切换规模小,为可靠切换高分辨率、大规模输入,高带宽与长距离视频信号,研究设计了一种基于AD8118视频切换芯片、LPC2478主控芯片的高分辨率128路输入32路输出平衡视频切换矩阵系统,给出了总体设计方案,硬件实现具体方案和原理图、软件任务流程图;在船坞修理厂、舰船停泊码头实际应用表明,系统运行稳定可靠,可实现大规模视频信号切换,减少了云台端切换设备数量,切换信号传输距离长,抗干扰能力强,准确且实时性好.     

基于压缩感知的低功耗高效率CMOS图像传感器设计

提出一种基于压缩感知的低功耗高效率CMOS图像传感器(CIS)设计.在这种压缩感知CIS中,帧存储、帧差求解和帧压缩等过程分别集成于像素级、列级和芯片级电路中,实现了图像传感过程和图像压缩过程的融合.这种融合提高了CIS在功耗、传输带宽和输出数据等方面的效率.所提出的CIS设计已采用Global Foundries 0...     

Novel 4T1C pixel circuit for high image quality OLEDoS microdisplays

A novel pixel circuit with a bulk‐driven technique is proposed for high image quality organic light‐emitting diode‐on‐silicon (OLEDoS) microdisplays. The proposed pixel circuit based on bulk‐driven technique achieves a wide input voltage range and nanoampere (nA) emission current. The experiment results based on the 0.18 μm 1P5M CMOS process is demonstrated. The input data voltage width of the proposed circuit is approximately 2.6 V. The ratio of the input voltage range to the supply voltage based on bulk‐driven 4T1C is 78.82%.     

High‐speed pixel circuits for large‐sized 3‐D AMOLED displays

Abstract— Large‐sized active‐matrix organic light‐emitting diode (AMOLED) displays require high‐frame‐rate driving technology to achieve high‐quality 3‐D images. However, higher‐frame‐rate driving decreases the time available for compensating Vth in the pixel circuit. Therefore, a new method needs to be developed to compensate the pixel circuit in a shorter time interval. In this work, image quality of a 14‐in. quarter full‐high‐definition (qFHD) AMOLED driven at a frame rate of over 240 Hz was investigated. It was found that image degradation is related to the time available for compensation of the driving TFT threshold voltage. To solve this problem, novel AMOLED pixel circuits for high‐speed operation are proposed to compensate threshold‐voltage variation at frame rates above 240 Hz. When Vth is varied over ±1.0 V, conventional pixel circuits showed current deviations of 22.8 and 39.8% at 240 and 480 Hz, respectively, while the new pixel circuits showed deviations of only 2.6 and 5.4%.     

Color error from an RGB‐stripe pixel structure

Abstract— Most direct‐view color displays have a sub‐pixel structure similar to the RGB‐stripe structure. The video data for R and B are produced on the condition that they are reproduced at the same position as G but they are displayed on the screen with 1/3 of a pixel separation from the corresponding G pixel. This pixel structure thus entails a convergence error of 1/3 of a pixel. The modified s‐CIELAB method was applied to investigate color errors produced by the RGB‐stripe pixel structure. The results show that the pixel structure can degrade the image quality even for a viewing distance where the pixel structure is not visible because the color difference caused by the structure has a low‐frequency component and the human vision can detect it. The same method was applied to the convergence error and it was shown that the necessary convergence accuracy is around 1/4 of a pixel.     

Pixel structures using the negative feedback method for high‐resolution active matrix organic light‐emitting diode displays

Novel two pixel structures are proposed for high‐resolution active matrix organic light‐emitting diode displays. The proposed two pixels (pixel structures A and B) use the negative feedback method for high‐resolution displays that requires to have small‐sized storage capacitance. The proposed pixel structures A and B improve the luminance uniformity by reducing the voltage distortion in the storage capacitor. However, the proposed pixel structure A is vulnerable to the organic light‐emitting diode (OLED) degradation because the anode voltage of the OLED affects the emission current. In order to compensate the OLED degradation, the proposed pixel structure B stores the turn‐on voltage of OLEDs in the storage capacitor. The simulation results show that the emission current error of the proposed pixel structure B is improved by four times in comparison with the proposed pixel structure A when the OLED turn‐on voltage increases by 0.1 V. Also, the emission current error of the proposed pixel structure B when the threshold voltage of driving thin‐film transistors varies from ?2.2 to ?1.8 V is from ?0.69 least significant bit (LSB) to 0.13 LSB, which shows the excellent luminance uniformity. The proposed pixels are designed for 5.5‐in. full high‐definition displays.     

Active matrix field sequential color electrically suppressed helix ferroelectric liquid crystal for high resolution displays

In this article, we disclose a 3‐inch 250ppi active matrix field sequential color (FSC) display based on electrically suppressed ferroelectric liquid crystal (ESHFLC). ESHFLC's ultra‐fast response time (~10 μs at 6.67 V/μm) enables the display resolution to be tripled via FSC technique. The photo‐alignment technology provides ESHFLC with optimal anchoring energy that contributes to a high contrast ratio over 10 K:1 on single pixel level measurement. A specific 3T1C pixel circuit is designed to generate continuous gray scale from FLC binary switching by utilizing the pulse width modulation concept. The low temperature poly silicon thin‐film transistor array has been used to fabricate the FSC ESHFLC display panel. We achieved an 8‐bit gray level for each color subframe, that is, R, G, and B colors that results in 24‐bit color images. We believe, because of the good optical quality and cost‐effective fabrication, this display may replace in‐plane switching or fringe‐field switching in the near future for the portable device market. Moreover, high resolution FSC ESHFLCs can find applications in the emerging virtual reality displays.     

A motion location based video watermarking scheme using ICA to extract dynamic frames

In this paper, we propose a novel video watermarking scheme based on motion location. In the proposed scheme, independent component analysis is used to extract a dynamic frame from two successive frames of original video, and the motion is located by using the variance of 8 × 8 block in the extracted dynamic frame. Then according to the located motion, we choose a corresponding region in the former frame of the two successive frames, where watermark is embedded by using the quantization index modulation algorithm. The procedure above is repeated until each frame of the video (excluding the last one) is watermarked. The simulations show that the proposed scheme has a good performance to resist Gaussian noising, MPEG2 compression, frame dropping, frame cropping, etc. This work was originally presented in the Fifth International Symposium on Neural Networks.     

基于宽波束激励的高帧频超声成像方法研究

超声成像的帧频是影响超声成像应用的一个关键因素,成像系统的帧频决定了系统捕捉运动组织的能力,如3D成像、心脏成像、彩色多普勒等。传统超声成像采用延迟聚焦方法可获得较好的图像,但成像帧频较低。目前提高超声成像帧频主要有平面波成像和宽波束激励成像两种方法。平面波成像是通过激励所有阵元同时发射并同时接收超声波,虽在帧频上获得了显著提高,但由于它使用非聚焦技术,分辨率的提高仍然比较有限,特别是当要维持较高帧率而使用较少的扫描角度时,得到的图像质量仍然不高。宽波束成像技术利用多阵元同时发射超声波、远点聚焦、动态实现孔径变迹等方法可极大地提高图像的帧频、均匀性和空间分辨率。文章通过美国 Verasonics公司 V-1数据采集系统采集宽波束数据,进行波束合成建立宽波束超声图像,并与平面波成像和传统聚焦成像技术进行了对比和分析。实验结果表明,相较于平面波成像和传统聚焦成像方法,宽波束成像具有更好的横向分辨率和轴向分辨率,且可获得比传统聚焦方法更高的帧频。     

High‐quality direct‐view display combining multiple integral 3D images

This paper proposes a method for combining multiple integral three‐dimensional (3D) images using direct‐view displays to obtain high‐quality results. A multi‐image combining optical system (MICOS) is used to enlarge and combine multiple integral 3D images without gaps. An optical design with a simple lens configuration that does not require a diffuser plate prevents the deterioration in resolution resulting from lens arrangement errors and the diffuser plate. An experiment was performed to compare a previously developed method with the proposed method, and the latter showed a significant improvement in image quality. A method for expanding the effective viewing angle of the proposed optical design was also developed, and its effectiveness was confirmed experimentally. A prototype device of the proposed optical design was constructed using a high‐density organic light‐emitting diode (OLED) panel with 8K resolution and 1058 ppi pixel density to achieve 311 (H) × 175 (V) elemental images, a viewing angle of 20.6° in both the horizontal and vertical directions, and a display size of 9.1 in. In addition, the proposed optical design enabled making device considerably thinner, ie, with a thickness of only 47 mm.     

Convolutional Sparse Coding for Capturing High‐Speed Video Content

Video capture is limited by the trade‐off between spatial and temporal resolution: when capturing videos of high temporal resolution, the spatial resolution decreases due to bandwidth limitations in the capture system. Achieving both high spatial and temporal resolution is only possible with highly specialized and very expensive hardware, and even then the same basic trade‐off remains. The recent introduction of compressive sensing and sparse reconstruction techniques allows for the capture of single‐shot high‐speed video, by coding the temporal information in a single frame, and then reconstructing the full video sequence from this single‐coded image and a trained dictionary of image patches. In this paper, we first analyse this approach, and find insights that help improve the quality of the reconstructed videos. We then introduce a novel technique, based on convolutional sparse coding (CSC), and show how it outperforms the state‐of‐the‐art, patch‐based approach in terms of flexibility and efficiency, due to the convolutional nature of its filter banks. The key idea for CSC high‐speed video acquisition is extending the basic formulation by imposing an additional constraint in the temporal dimension, which enforces sparsity of the first‐order derivatives over time.