A consideration on motion‐image‐quality improvement of LCDs and video systems

Abstract— The motion image quality of video systems with hold‐type displays, such as LCDs or OLEDs, were studied with regard to dynamic spatial frequency response and data from subjective evaluations on motion blur. The system parameters of motion image quality, or frame rate (F) and temporal aperture (A^t), were investigated and their required values were derived. A smaller temporal aperture and/or higher frame rate can improve the dynamic response and motion image quality, but the parameters required in order to maintain a good dynamic response for high motion image velocity seems very difficult to implement, such as a frame rate of 900 Hz. Therefore, the performance goal of video systems is set on “limit of acceptance” for motion image quality, as a compromise. An equation or the relational expression between motion image velocity and required parameter values is derived based on dynamic response and data from subjective evaluations found in published studies. Possible examples of parameter sets are obtained from the equation. Those are (F = 300 Hz, A_t = 5/6), (F = 240 Hz, A_t = 2/3), (F = 120 Hz, A_t = 1/3), and (F > 360 Hz, A_t = 1).     

Improvement of 3D visual image quality by using high frame rate

The relationship between high frame rate and depth perception was investigated. Psychophysical experiments using moving random dot stereograms to study depth discrimination under several conditions showed that three‐dimensional motion images produced and displayed with a frame rate of 240 fps enable finer discrimination of depth for the viewer compared with frame rates of 120 or 60 fps. In addition, overall evaluations of natural three‐dimensional motion images by viewers confirmed that more natural motion and depth impressions were presented at 240 fps than at lower frame rates. Further, the results are discussed with reference to a recent theoretical model of the dynamic spatial frequency response of the camera/display system.     

A system approach to high‐quality picture‐rate conversion

Abstract— Various techniques have been implemented to improve the motion portrayal of flat‐panel displays, of which the widespread introduction of motion‐compensated picture‐rate conversion systems is an essential part. However, a careful design of such systems is critical as they have the potential to introduce perceptually annoying artifacts. In this paper, an overview of the required “ingredients” of high‐quality motion‐compensated picture‐rate conversion is presented, as implemented in state‐of‐the‐art systems‐on‐chip. The visual impact of individual components on picture quality is illustrated.     

Study of image quality using event‐related potentials and eye tracking measurement

The image quality was investigated using electroencephalography and eye‐tracking measurements simultaneously. Different image qualities were obtained by changing σ values in the Gaussian kernel function. The experimental results illustrated that the measurable event‐related potentials and eye‐tracking parameters varied with the change of the image quality. The more blurred the image, the higher and earlier the P300 (event‐related potentials at latency about 300–550 ms) was elicited. Meanwhile, the visual fixation duration decreased and the detection rate increased with the increase of σ. The blurred image quality could be evaluated based on the synthetic results of the reciprocal of P300 latency and the visual fixation duration. The result showed a good correlation with the subjective rating scores, which proved the feasibility of utilizing electroencephalography and eye‐tracking technology to evaluate the blurred image quality.     

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.     

Effects of motion image stimuli with normal and high frame rates on EEG power spectra: comparison with continuous motion image stimuli

The human electroencephalographic (EEG) power spectra when viewing visual stimuli of a real motion image and of motion images with 60 frames/s (fps) and 240 fps were investigated. The EEG spectra in response to the 240 fps motion image stimuli were more similar to those of the real motion image stimuli than those of the 60 fps stimuli. This high frame rate (240 fps) motion image is considered to have a possibility of providing perceptions of motion image quality that are close to the impression upon looking at real world scenes.     

高帧频二维数字图像数据采集速率控制系统设计

为解决传统数据采集速率控制系统存在的采集速率较低,采集精度较低等问题,提出高帧频二维数字图像数据采集速率控制系统设计。充分考虑数据采集速率控制需求,选用KPCI-811数据采集卡对系统硬件部分的数据采集电路和电源电路进行改进,优化软件部分的数据采集、数据过滤及数据采集效率控制功能,完成高帧频二维数字图像数据采集速率控制系统的设计。实验结果表明,较传统系统,该系统的采集耗时更少,采集速率更高,采集精度更高,满足数据采集速率控制需求。     

Simple pixel circuits for high resolution and high image quality organic light emitting diode‐on‐silicon microdisplays with wide data voltage range

Two simple pixel circuits are proposed for high resolution and high image quality organic light‐emitting diode‐on‐silicon microdisplays. The proposed pixel circuits achieve high resolution due to simple pixel structure comprising three n‐type MOSFETs and one storage capacitor, which are integrated into a unit subpixel area of 3 × 9 µm² using a 90 nm CMOS process. The proposed pixel circuits improve image quality by compensating for the threshold voltage variation of the driving transistors and extending the data voltage range. To verify the performance of the proposed pixel circuits, the emission currents of 24 pixel circuits are measured. The measured emission current deviation error of the proposed pixel circuits A and B ranges from ?2.59% to +2.78%, and from ?1.86% to +1.84%, respectively, which are improved from the emission current deviation error of the conventional current‐source type pixel circuit when the threshold voltage variation is not compensated for, which ranges from ?14.87% to +14.67%. In addition, the data voltage ranges of the proposed pixel circuits A and B are 1.193 V and 1.792 V, respectively, which are 2.38 and 3.57 times wider than the data voltage range of the conventional current‐source type pixel circuit of 0.501 V.     

A reduction method of dynamic false contour utilizing the frame‐rate‐control method with suppression of the side effect on PDPs

Abstract— The plasma‐display panel (PDP) is a type of flat‐panel display that can display a high‐quality image. However, when moving images are displayed, annoying disturbances such as false contour noise occurs. This noise is called dynamic false contour (DFC). To achieve a higher‐quality image, DFC has to be reduced. Therefore, a new method to reduce DFC is proposed. To find a way to reduce DFC, a new evaluation value for it has been defined: the evaluation value of dynamic false contour (EVDFC). This value is defined on the basis of a person's subjective evaluation. By applying this value, the cause that generates DFC can be identified. On the basis of these studies, a new method for reducing DFC by applying frame‐rate control (FRC) with suppression of the side effect is proposed. This improved method can be used to provide high‐quality images.     

Ambient‐light‐adaptive image quality enhancement for full‐color e‐paper displays using a saturation‐based tone‐mapping method

Full‐color e‐paper displays that have a small color gamut encounter image tone distortions and contour artifacts in high‐saturation regions. To solve these issues, in this paper, we comprehensively measure the colorimetric responses of input image signals and demonstrate that the perceptual colorfulness in terms of chroma abnormally declines when the input saturation is beyond a certain value. Accordingly, saturation‐based tone‐mapping curves are developed to map the abnormal high saturation to the range that the display is able to normally render. By testing several test charts and natural images, the recoveries of the original image tones and the removals of the contour artifacts are experimentally verified. More important, by discussing how to conduct a database of tone‐mapping curves for different ambient lights and utilize the database for an unknown ambient light, the proposed method is proven to be completely ambient light adaptive.     

Thermal‐deformation characterization of the panel of a TFT‐LCD TV. Part II: Solutions to thermal‐induced extrusion degrading image quality

Abstract— The first paper of this series of papers explored the thermal deformation of a panel causing color distortion on TFT‐LCD TV panels. The heat source from CCFLs leads to thermal deformation of the LCD panel that extrudes the metal front shield and degrades image quality. The second part of this series of papers proposes two solutions to tackle the thermal deformation of the panel and improve image quality. In addition to developing a reliable procedure for the characterization of this thermal phenomena on the LCD panel, the goal of this work is to consider and justify two design modifications through numerical analysis and experimentation to reduce thermal deformation and color distortion. One modification provides heat dissipation on the direct‐lit BLU by opening apertures which effectively lower the temperature distribution in the BLU and on the panel without adding extra heat‐dissipation modules. The other modification adds partition pads to reserve an appropriate gap between the panel and the front shield for the prevention of extrusions even after thermal deformation of the panel. The applied approaches for soothing color distortion can be broadened to other TFT‐LCD TV products.     

Neuro‐filters used to enhance the image quality of video displays

Abstract— Digital images can be affected by external factors. There are many types of noise which affect digital images. Image filtration is a basic method used to suppress such hindrances. The disadvantage of most filtration methods and hardware filters created on their behalf is their inability to react to changes in the input signal. The structure of the filters used for image processing is similar to the structure of a bi‐dimensional neural‐network matrix. Investigations have shown that a system with serial‐parallel filters of any degree of complexity can be created on the basis of the neural‐network matrices. Each neural‐network matrix layer acts as a separate neuro‐filter which can be trained and adapted to changes in the characteristics of the images. The neural‐network matrices allow for the creation of various types of linear and nonlinear filters, as well as combinations on the basis of a uniform structure. It allows for the design of a universal hardware neuro‐filter structure that can perform as different types of filters by means of loading the connectors weight. In our paper, we consider the realization of neuro‐filters based on a neural‐network matrix, which allows the processing of both static and moving images and increases the image sharpness, suppresses the noise, and detects movable objects in the processed image.     

Influence of image‐quality degradation on accommodation mechanism in human vision: Conditions necessary for objective image‐quality evaluation metrics

This paper clarifies the relationship between image quality and accommodation in human vision through two types of experiments. One examines how image‐quality degradation influences the accommodation mechanism, and the other examines which type of information of quality‐degraded images activates the accommodation mechanism. Actually, accommodative responses are measured using an infrared optometer while subjects are subjectively evaluating sharpness, noise, and pseudo‐contours and while they are observing sine, square, and missing fundamental (MF) square waves. The following results were derived: (1) the accommodation lag increases as the degree of sharpness is degraded regardless of the tone‐reproducing methods; (2) the accommodation lag decreases considerably in the existence of noise or pseudo‐contours, whereas it increases for uniform or gently curved planes; (3) the spatial features of presented images activate the accommodation mechanism. These results suggest that accommodative responses influence human subjective judgments as well as being a human factor related closely to image quality and that the spatial features of quality‐degraded images underlie human subjective judgments. In other words, they imply that objective image‐quality evaluation metrics should satisfy the following two conditions: the incorporation of the accommodation characteristics into such metrics and the formulation of such metrics in the spatial region.     

A 550‐PPI LCD using 1.5 µm channel width LTPS TFTs with low frame rate driving

A 550 PPI low‐temperature polycrystalline silicon thin‐film transistor liquid‐crystal display has been developed. Shrinkage of the channel width of pixel thin‐film transistor together with thinner insulator for the storage capacitor allows high display quality in terms of vertical cross‐talk and flicker. Thirty hertz frame rate driving is implemented to offer low power while keeping high display quality.     

Comparison of image reconstruction by using near‐field and far‐field data for an imperfect conductor

Image reconstruction by using near‐field and far‐field data for an imperfectly conducting cylinder is investigated. A conducting cylinder of unknown shape and conductivity scatters the incident wave in free space and the scattered near and far fields are measured. By using measured fields, the imaging problem is reformulated into an optimization problem and solved by the genetic algorithm. Numerical results show that the convergence speed and final reconstructed results by using near‐field data are better than those obtained by using far‐field data. This work provides both comparative and quantitative information. © 2001 John Wiley & Sons, Inc. Int J RF and Microwave CAE 11: 69–73, 2001.     

A perceived sharpness metric based on the luminance slope and overshoot of the motion‐induced edge‐blur profile

To reduce perceived motion blur on liquid crystal displays, typically various techniques such as overdrive, scanning backlight, black‐data insertion, black‐field insertion, and frame rate up‐conversion are widely employed by the liquid crystal display industry. These techniques aim to steepen the edge transitions by improving the dynamic behavior of the light modulation. However, depending on the implementation, this may result in the perception of irregularly shaped motion‐induced edge‐blur profiles. It is not yet fully understood how these irregularities in the steepened edge‐blur profiles contribute to the perceived sharpness of moving objects. To better understand the consequences of several motion‐blur reduction techniques, a perception experiment is designed to evaluate the perceived sharpness of typical motion‐induced edge‐blur profiles at several contrast levels. Relevant characteristics of these profiles are determined on the basis of the perception results by means of regression analysis. As a result, a sharpness metric with two parameters is established, where one parameter relates to the edge slope and the other to the overshoot/undershoot part of the motion‐induced edge‐blur profile.     

IPS‐mode dynamic LCD‐TV realization with low black luminance and high contrast by adaptive dynamic image control technology

Abstract— In this paper, an active backlight control technology and a data‐processing algorithm has been developed to improve the image quality in IPS‐mode LCD TVs. The image‐blinking problem caused by repeatedly abrupt changes in the backlight luminance was solved by using algorithms [Fba (flexible‐boundary algorithm) and Cfa (cumulative feedback algorithm)] and an optimized number of backlight dimming steps based on human perception. In the IPS‐mode 42‐in. TFT‐LCD panel, the dynamic contrast ratio can be more than twice the typical level by means of a lower black luminance and a higher white luminance. Additionally, the power consumption and LCD temperature were lowered.     

Large improvements in application throughput of long‐running multi‐component applications using batch grids

Computational grids with multiple batch systems (batch grids) can be powerful infrastructures for executing long‐running multi‐component parallel applications. In this paper, we evaluate the potential improvements in throughput of long‐running multi‐component applications when the different components of the applications are executed on multiple batch systems of batch grids. We compare the multiple batch executions with executions of the components on a single batch system without increasing the number of processors used for executions. We perform our analysis with a foremost long‐running multi‐component application for climate modeling, the Community Climate System Model (CCSM). We have built a robust simulator that models the characteristics of both the multi‐component application and the batch systems. By conducting large number of simulations with different workload characteristics and queuing policies of the systems, processor allocations to components of the application, distributions of the components to the batch systems and inter‐cluster bandwidths, we show that multiple batch executions lead to 55% average increase in throughput over single batch executions for long‐running CCSM. We also conducted real experiments with a practical middleware infrastructure and showed that multi‐site executions lead to effective utilization of batch systems for executions of CCSM and give higher simulation throughput than single‐site executions. Copyright © 2011 John Wiley & Sons, Ltd.     

Dual open‐slot antennas integrated in metal frame and metal case of tablet computer for long‐term evolution applications

Dual open‐slot antennas were integrated in the metal back case and metal frame of a tablet computer for long‐term evolution applications. The single feed dual excitation source antennas were sufficiently narrow (2 mm) for installation between the metal frame and metal back case of the tablet computer. Each antenna had two open‐slot radiators (slot 1 and slot 2) with embedded filter circuits to enable wideband (699‐906 and 1710‐2690 MHz) operation required for LTE applications. The filter circuit values were adjusted to make the impedance more smooth and excite the desired modes. The proposed multiple‐input‐multiple‐output antennas were installed lengthwise on the long sides of the tablet and facing in operate directions. In this configuration, the user hand grip did not interfere with antenna performance, and isolation was improved (> 20 dB). The operating mechanism of the proposed antenna with matching circuits is described in detail. The effects of the user hand grip and the embedded display panel are also discussed.     

A case study: productivity and quality gains using an object‐oriented framework

The Neuro‐Oncology Information System (NOIS) supports researchers and other personnel throughout the United States engaged in brain tumor research. Graphical user interfaces that allow data input into the NOIS have been evolving over several years. This paper describes the design and implementation of the NOIS Input Forms as they migrated from a procedural approach to a static object‐oriented approach, and finally to a framework approach in which not only static components were reused, but also the patterns of interaction among the components. The paper documents a significant gain in productivity and quality that was realized when using the framework design paradigm. Copyright © 1999 John Wiley & Sons, Ltd.