Reducing the memory of compression Feedforward driving for a new LCD controller

Abstract— The authors have studied a method of reducing the frame memory for signal processing used to improve the response time of liquid crystals. Compared with cases in which quantization is used, the compression Feedforward driving method, which reduces frame memory by applying an image‐compression technique, can effectively reduce the frame‐memory size. The study revealed that errors decrease by 6–10 dB or so if the image data was reduced to 1/3 by means of image compression. Based on the results of the study, the authors have developed a second‐generation LCD controller. With just one SDRAM unit, this LCD controller can produce almost ideal processing effects.     

An adaptive generation method for electrophoretic display driving waveform design

Electrophoretic display (EPD) technology is attractive when used for reading devices such as e‐paper because of its paper‐like appearance. EPD driving is more complex than other display technologies such as liquid crystal display or organic light emission diode because the driving result of a pixel strongly depends on the initial display state. The particle size and distribution in the EPD film may vary, even if the initial state is the same. Therefore, the display devices vary between different manufacturing batches. Furthermore, different display modes such as videos, pictures or documents need different driving waveforms to achieve an optimal result. EPD manufacturers need to build a customized driving waveform for every manufacturing batch. This is very inconvenient if new applications on EPD are to be developed. And the workload is huge. In this work, an adaptive method is described for automatically creating EPD driving waveforms to fit different conditions. The central idea of this method is generally adjusting the driving time and the voltage state after getting the feedback from a measurement model. In this method, a new driving waveform is used to reduce refresh time and visual flicker. The experimental results show that the proposed approach can automatically and adaptively generate an EPD driving waveform with reasonable quality.     

The design and optimization of lens array for LED backlight in LCD imaging engine of helmet‐mounted display

The light‐emitting diode has become the mainstream lightsource for backlight in the liquid crystal display imaging engine of helmet‐mounted display. The paper proposes a secondary‐optics‐based design to increase the luminance and obtain a uniform illumination. Based on a point lightsource, a single double‐freeform‐surface lens is firstly designed. Then an optimization is performed according to the theory of edge‐ray to improve the uniformity for planar source. As a result, the uniformity reaches 83.4% in a circular illumination with a diameter of 8 mm. Then the lens is cut and four rectangular lenses are combined to form a lens array. But the combination leads to a non‐uniformity. So a method of optimizing the light energy distribution on the target surface is proposed. Finally, the designed lens array is manufactured. The practical measurement results show that the luminance increases by 96.4% compared with the traditional backlight and that the non‐uniformity slightly decreases by 0.86%. The lens array designed in this paper presents high practicability for applications in helmet‐mounted display.     

A portable driving system for high‐resolution active matrix electrowetting display based on FPGA

How to display pictures and even videos on electrowetting displays (EWDs) still needs improvement. Therefore, we seek to develop a robust, portable and scalable system for the realization of high‐resolution EWDs. In this paper, a driving system for an 8 inch active matrix electrowetting display (AM‐EWD) based on a Field‐Programmable‐Gate‐Array (FPGA) is proposed, where the key components are an active matrix backplane, an FPGA driving waveform and driver integrated circuits (ICs). We successfully demonstrate an AM‐EWD with 1024×768 resolution and 16‐level gray‐scale realized by unique dynamic and asymmetric sub‐frame of FPGA. The whole system is just powered by a 3.7V 1100mAH lithium battery. Such a system has not been reported before, also well‐suited for transferring to a higher performance portable EWD in the future.     

A new low‐power driving method for high‐resolution mobile IPS LCDs

Abstract— High‐resolution displays are now needed for mobile equipment, not only for cell phones but for other devices such as ultra‐mobile PCs (UMPCs) and mobile Internet protocol televisions (IPTVs). A new low‐cost and low‐power driving method for high‐resolution in‐plane‐switching (IPS) liquid‐crystal displays (LCDs) on a low‐temperature polycrystalline‐silicon (LTPS) thin‐film‐transistor (TFT) platform has been developed. Because this method drives common electrodes separated by each line, it can reduce inversion frequency, unlike “dot‐inversion” or “column‐inversion” methods. On the other hand, it was found that horizontal smear is an obstacle to achieve this method. To solve this problem, techniques to optimize the timing of RGB time‐sharing are proposed. A 5‐in. WXGA (1366 × 768) prototype using the new driving method was fabricated, and it was found that the horizontal smear is less than ±1% of the luminance and that the power consumption of the display discharge and charge is 0.245 W.     

Anode‐voltage‐control circuit for compensation of luminance deterioration

Abstract— An external driving circuit that has realized long lifetime, power‐consumption control, and peak luminance for organic light‐emitting diode (OLED) displays have been developed. This circuit realizes an effective method for constant‐anode‐voltage (CV) driving refered to as clamped inverter (CI) driving. The feature of CV driving is to achieve low‐power consumption compared with constant‐anode‐current (CC) driving and to control the power consumption and peak luminance according to the image because display luminance can be easily changed by controlling the anode voltage. On the other hand, CV driving has the problem that luminance deterioration appears to be serious compared with that of CC driving because the current of the OLED element decreases according to usage time. To cope with this, a lifetime compensation circuit that has increased the anode voltage so that it compensates for the luminance deterioration has been developed. This circuit can compensate not only the decrease in current but also the decrease in luminance at a constant current that CC driving cannot. However, increasing the anode voltage causes an increase in stress on the OLED element. The influence of stress on OLED lifetime was verified. As a result, it was confirmed that this circuit can extend the lifetime by 32% even if the anode voltage is increased, causing stress on the OLED structure.     

A new driving method to compensate for row‐line signal‐propagation delays in an AMLCD

Abstract— The row‐line and data‐line that make up of a TFT‐LCD panel can be modeled as a distributed resistance and capacitance network. As TFT‐LCD panels become larger and provide higher resolution, the induced signal propagation delay time from the row and column lines become an appreciable part of the line time. In particular, the row signal‐propagation delay time is traditionally accommodated by waiting for the worst‐case propagation time before the start of a new line. This conventional method, however, reduces the subpixel charging time. A new driving method, Horizontal Line Delay Compensation (H‐LDC), has been implemented and verified to compensate for row‐line propagation delay. The benefit of longer subpixel charging time is of particular interest to large‐area high‐resolution fast‐refresh‐rate LCD TVs.     

A survey of deep learning techniques for autonomous driving

The last decade witnessed increasingly rapid progress in self‐driving vehicle technology, mainly backed up by advances in the area of deep learning and artificial intelligence (AI). The objective of this paper is to survey the current state‐of‐the‐art on deep learning technologies used in autonomous driving. We start by presenting AI‐based self‐driving architectures, convolutional and recurrent neural networks, as well as the deep reinforcement learning paradigm. These methodologies form a base for the surveyed driving scene perception, path planning, behavior arbitration, and motion control algorithms. We investigate both the modular perception‐planning‐action pipeline, where each module is built using deep learning methods, as well as End2End systems, which directly map sensory information to steering commands. Additionally, we tackle current challenges encountered in designing AI architectures for autonomous driving, such as their safety, training data sources, and computational hardware. The comparison presented in this survey helps gain insight into the strengths and limitations of deep learning and AI approaches for autonomous driving and assist with design choices.     

Two‐parameter optimization procedure for a TN display

Abstract— In our work, a two‐parameter optimization procedure for a TN display has been performed. The procedure consists of the numerical calculation of the optical parameters of a TN display, such as contrast ratio and luminance as a function of both the LC‐layer dichroic properties and the polarization coefficient of the polarizers used. The calculations have been done for: human eye sensitivity; real spectral characteristics of light sources (both internal and external ones); both the positive and negative modes of operating of the display; real director profile of the LC layer. Additionally, our procedure takes into account the interference phenomena of the display and the quasi‐real properties of the polarizing films. As a result of our work, a close relationship between the TN display optical parameters and the dichroic LC layer and polarizing films used have been obtained. This makes it possible to choose the initial display elements for different display application and user requirements.     

A method for reproducing apparent continuous depth in a stereoscopic display using “Depth‐Fused 3D” technology

Abstract— A new method that can present fine depth increments in a stereoscopic display is proposed. In typical stereoscopic displays, depth can be presented by binocular disparity, but binocular disparity of less than one pixel cannot be displayed because, in general, electronic displays have discrete pixels. We combined binocular disparity and modulation of the edge luminance in DFD (depth‐fused 3D) displays. In an experiment, the perceived depth could be continuously changed by modulating the edge luminance only. Therefore, continuous depth can be produced by combining binocular disparity and modulation of edge luminance distribution.     

自动驾驶模糊神经网络速度规划方法

为提升自动驾驶的舒适性,降低速度规划算法的复杂度,提出了一种基于模糊神经网络的纵向速度规划方法。将人工驾驶经验总结为模糊规则表,建立了模糊速度规划模型,结合神经网络的自学习功能修正模糊速度规划模型,建立了模糊神经网络速度规划模型。分析了静态障碍物和动态障碍物场景,通过仿真验证了所提速度规划方法的可行性,与传统方法相比,加速度的平滑性能更好。所提速度规划方法具有一定的抗干扰性能,工程实现简单,保证了速度规划的实时性与稳定性。     

A method for selecting display primaries to match a target color gamut

Abstract— A method for selecting primaries of a wide‐gamut display is proposed, in which display color gamut is designed to match a target color gamut in CIELAB color space. A standard deviation of the relative maximum chroma of display and target color gamuts is defined. The selection method optimizes display primaries for the minimum standard deviation so that display and target color gamuts are similar in shape. It is shown that the color gamut of a laser display designed by this method is similar in shape to the theoretical maximum, or optimal, color gamut of objects. It is also shown that the color gamut of an LED display can be designed to include 99.7% of the gamut of Pointer's real‐world surface colors. LED primaries are selected to minimize the standard deviation of the relative maximum chroma of effective display color gamut and a target color gamut which is defined to include Pointer's real‐world surface colors. For both the laser and LED displays, it is necessary to constrain the red‐primary wavelength to avoid excessive optical power for the red primary.     

Shrunk multiline addressing method in a passive‐matrix‐driven liquid powder display

Abstract— A shrunk multiline addressing method (SMLA) in a passive‐matrix‐driven liquid powder display will be discussed. An algorithm to generate SMLA data that effectively reduces the number of scanning lines has been devised. The update time is reduced by 44.5% on average, and this reduction is maintained despite increased sizes of the images. The SMLA data generated by this algorithm is applied to e‐paper panels, thereby confirming the reduction in update time and that the image quality of the panels driven by SMLA is equal to that of conventionally driven ones.     

New pixel driving circuit using self‐discharging compensation method for high‐resolution OLED micro displays on a silicon backplane

A new 4T2C pixel circuit formed on a silicon substrate is proposed to realize a high‐resolution 7.8‐μm pixel pitch AMOLED microdisplay. In order to achieve high luminance uniformity, the pixel circuit compensates its Vth variation of the MOSFET for the driving transistor internally by using self‐discharging method. Also presented are 0.5‐in Quad‐VGA and 1.25‐in wide Quad‐XGA microdisplays with the proposed pixel circuit.     

An area‐ratio gray‐scale method to achieve image uniformity in TFT‐LEPDs

Abstract— An area‐ratio gray‐scale method (ARG) has been developed for low‐temperature‐polysilicon thin‐film‐transistor‐driven light‐emitting‐polymer displays (LTPS TFT‐LEPDs). A pixel consists of plural sub‐pixels, which are controlled to be in either an on‐state or off‐state. The gray scale is acquired by selecting the number of the on‐state sub‐pixels, that is, the ratio of the light‐emitting area. One advantage of the ARG is to improve image uniformity. In the on‐state, since TFT resistance is negligible, the current is determined by the LEP diode resistance. Therefore, the TFT characteristic deviation has no effect on the current. Moreover, the dimensions of each sub‐pixel are the same, and the shapes of the sub‐pixel are circular in order to improve their uniformity. As a result, the image becomes uniform. Another advantage of the ARG is to achieve digital operation, which makes interfacing easy. A digital‐analog converter (DAC) automatically exists in the sub‐pixel and the naked eye.     

A high image quality organic light‐emitting diode display with motion blur reduction for ultrahigh resolution and premium TVs

In this paper, we present a high image quality organic light‐emitting diode (OLED) display with motion blur reduction technology. Our latest work includes driving method that reduces motion blur using an adaptive black data insertion, brightness compensation technology, the simple structure pixel with low capacitance coupling for horizontal noise, and the multifunction integrated gate driver. The moving picture response time (MPRT) value of the OLED display panel with a fast response time was significantly affected by the frame frequency and the compensation driving method. The MPRT value of the large‐size OLED display panels was significantly decreased by using the integrated gate driver circuit with an MPRT reduction method. The decrease in the MPRT value originated from the turning of the emitting pixels off in advance resulting from providing black data. The integrated gate drivers were designed to achieve the normal display, the black data insertion, and the compensation mode. The MPRT value of the 65‐in. ultrahigh‐definition (UHD) OLED panels was decreased to 3.4 ms by using an integrated gate driver circuit. The motion blur of large‐size OLED display panels was significantly reduced due to a decrease in the MPRT value.     

A study on a driving method of OLED displays for better motion image quality with adaptive temporal aperture control

Degradation of motion image quality by motion blur on hold‐type displays, such as liquid‐crystal displays and organic light‐emitting diode displays, is a well‐known issue. To improve motion image quality, a driving method with a shorter temporal aperture has been proposed. However, a shorter temporal aperture requires higher instantaneous luminance on displays. Higher instantaneous luminance accelerates the lifetime degradation of organic light‐emitting diode. Therefore, we have been developing a driving method with adaptive temporal aperture control for a longer lifetime and better motion image quality. However, two image quality degradations were perceived when this driving method was applied. One of these degradations was caused at the boundary between the different temporal apertures. The other degradation was caused by switching the temporal aperture between frames. Hence, we have also proposed transition area and period insertion methods to suppress these degradations. In this paper, we discuss the mechanism of these degradations and confirm the effectiveness of our proposed methods by subjective evaluations. In the results, the degradations were suppressed by inserting 80 lines of transition area and by inserting 50 frames of transition period.     

A new level set method for inhomogeneous image segmentation

Intensity inhomogeneity often appears in medical images, such as X-ray tomography and magnetic resonance (MR) images, due to technical limitations or artifacts introduced by the object being imaged. It is difficult to segment such images by traditional level set based segmentation models. In this paper, we propose a new level set method integrating local and global intensity information adaptively to segment inhomogeneous images. The local image information is associated with the intensity difference between the average of local intensity distribution and the original image, which can significantly increase the contrast between foreground and background. Thus, the images with intensity inhomogeneity can be efficiently segmented. What is more, to avoid the re-initialization of the level set function and shorten the computational time, a simple and fast level set evolution formulation is used in the numerical implementation. Experimental results on synthetic images as well as real medical images are shown in the paper to demonstrate the efficiency and robustness of the proposed method.     

A perceptually optimized mapping technique for display images

Liquid crystal displays (LCDs) are often viewed in the energy‐saving mode or under high ambient illumination. However, both these conditions compress the tonal dynamic range of the display device, resulting in undesirable visual perception effects. In this paper, we propose a local algorithm for improving the display image quality under either of these conditions. The proposed algorithm is based on a tone mapping technique, and it reproduces the image appearance to almost its original quality with a lower dynamic range. We also develop a more accurate definition of the image distortion, which takes into account the difference in pixel values to reduce the distortion significantly. By minimizing the differences in contrast and pixel intensity between the input and output images, the algorithm preserves the contrast while simultaneously providing brightness compensation. Simulation results show that the proposed algorithm can effectively maintain image quality while enabling power savings of 30%–50%.     

无监督聚类在锂离子电池分类中的应用

单体电池的一致性,决定了电池组的性能,如何选出性能一致的单体电池又一直是电池组研究中的重点所在。本文采集了100个合格锂离子电池的6项性能指标(老化前后电压、容量、内阻、1C放电平台、电芯厚度),运用主成分分析(PCA)、核主成分分析(KPCA)、随机森林(RF)3种无监督聚类方法,对数据结构进行了研究。结果表明,数据指标之间存在复杂的非线性关系,主成分分析和核主成分分析,均未能形成明显聚类,但随机森林数据在低维空间显然形成4类,任意从中选4个电池组成电池组作循环性能仿真测试,结果显示由由该方法挑选出的单体电池具有较好的一致性。